Learning from home!
The Education Department wants to bring the learning home to you. Please utilize the resources we have below to encourage science exploration and to supplement learning while we are all at home.
Learn what makes a seabird a seabird and why sharks are so well adapted to life in the water. View the individual animal information profiles below with all you wanted to know about their species.
Sea Life Park Hawaii is home to the only active breeding colony of green sea turtles in the entire United States. This means that the sea turtles you see here reproduce every season. Every year after mating the females go up on to that sandy beach and lay their eggs, or clutch. They can lay up to 5 clutches per breeding season. Each clutch can have anywhere from 60-120 eggs. After about 60 days and then we collect the hatchlings and release them into the ocean. So far here at Sea Life Park Hawaii, we have released over 16,000 baby sea turtles! Some juvenile turtles from the park can be seen at other educational facilities throughout the islands and part of the educational and outreach programs we have through our partnerships and loan programs. Before being released to the ocean we “PIT” tag the hatchlings where they receive a microchip in their back flipper. These tags provide a permanent method of identifying and tracking the turtles that we release so we can further collect data on where the turtles are heading.
How old do you think these sea turtles are? These sea turtles were donated to Sea Life Park Hawaii in the 1970’s, so we estimate that they are at least 60 years old; but may be as old as 70 or 80. Green sea turtles live to be anywhere between 80 to 100 years old.
How do green sea turtles (known in the Hawaiian language as honu, scientific name chelonia mydas) get their name? From what they eat, or their diet! Adult green sea turtles are completely herbivorous, or vegetarian. They eat algae, or seaweed, off of the coral reef. They eat so much green stuff that their subdermal layer of fat, inside their body is stained green in color.
How do you tell the difference between a male and a female sea turtle? You can identify males vs females by the length of their tail once the sea turtle is a mature adult. Maturity is reached as early as 10 and as late as 50 years old. An adult male has a long dinosaur like tail, while females have short, stubby tails. What type of animal is a green sea turtle is? It’s a reptile.
What are some characteristics of a reptile?
They lay eggs.
They have backbones! Their backbone is attached to their shell!
They are cold-blooded: What does cold-blooded mean? It means that their body temperature changes to match the temperature of their environment.
They breathe air. All reptiles breathe air. They have lungs similar to humans. Honu have a special ability to lower their heart rate. This allows adults to hold their breath for up to 2 hours.
They have scaly skin. Even their shell is made up of modified scales called scutes. Hawaiian Green Sea Turtles have 13 scutes!
Green sea turtles do not have teeth; however they have a beak with a very sharp jagged edge. This allows them to scrape the algae off of the reef and off of rocks. Moving down their body, they have specially modified front flippers that help them swim, while their hind limbs enable them to steer. The shell of a green sea turtle consists of two parts, the carapace and the plastron. The carapace is the top or back of the shell and is covered with 13 scutes, or scales, on average. The underside of a turtle is known as the plastron. You will notice that the belly of the sea turtle is a lighter color. This is a type of camouflage called countershading, so their dark carapace blends in with the dark ocean floor; and the lighter plastron blends in with the sky and light coming in from above. This countershading helps to protect them from predators.
This habitat, like all of our habitats at Sea Life Park Hawaii, contains real ocean water. Sea Life Park Hawaii pumps about 12 million gallons of fresh sea water through our habitats every day. We do not put any kind of chemicals into that water, so algae grows naturally in our habitats. This algae called diatoms actually absorbs harmful sunlight and produces atmospheric oxygen. This algae may also grow on sea turtles. It can be seen on their scales or shell. In the wild, sea turtles visiting something called a cleaning station, which is a place on the reef where fish come and eat the algae off of the sea turtle. The turtle is getting clean, and the fish is getting fed; this is what is called symbiotic relationship in which both animals benefit from the partnership. We do not have those fish in our habitat, so twice a week we drain the habitat and our staff scrub the sea turtles clean!
All sea turtles have different patterns and colors on their shells. Our turtles may look different than wild turtles that you see because their shells are kept clean from being scrubbed. However, when sea turtles first hatch from the egg, they are a dark grey almost black color. If you get to see one of the juveniles at our touch pool today you will notice this color difference. When a Hawaiian green sea turtle hatches it is about 2 inches and weighs around 1 oz.; which is about the size of a golf ball! On average, they can grow to have a shell length of 36 inches and weigh about 250lbs.
Only about 1 in 1,000 sea turtle hatchlings survive until maturity. What kinds of dangers do you think they face as the make their way from their nest to the ocean? Threats to green sea turtles include crabs, seabirds, heat from the sun, humans, and several other threats; but if they make it to the ocean the threats don’t end there. Sharks, large fish, and human interaction such as nets and marine debris also threaten their pelagic lifestyle. When sea turtles first hatch, they make their way out into the open ocean and spend 4-10years there. This is called their pelagic life style. A pelagic lifestyle is where a turtle will float around at the surface of the water, and will not typically be seen until it returns to the nesting beaches as an adult. During this time, the juvenile sea turtle is an opportunistic feeder, which means that it eats whatever it can find. They may be eating squid, fish, or anything floating on the surface of the ocean. Our juvenile sea turtles are fed krill, squid, and fish like ahi.
Hawaiian green sea turtles were listed as endangered, however due to being protected by Hawaii state and federal law as well as the Endangered Species Act; their status has now been moved to threatened. This is better, but our goal is to get them off of this list completely. Therefore, you should not threaten, hunt, feed, or harass green sea turtles in the wild. Hawaiian green sea turtles have been known to come up on to the beaches; and it is very important to leave them alone when they do this, so that they can get the rest and warmth that they need to survive. Unfortunately, disease, marine debris, and net entanglements also threaten these turtles. What is marine debris? Marine debris is our trash that ends up in the ocean.
For all of these threats to green sea turtles, you can help by picking up your trash; and even taking it a step further by picking up someone else’s trash to reduce the amount of marine debris found in our oceans. If you see a turtle in distress you should not attempt to come to the turtle’s aid; instead you can call the appropriate agencies to assist with turtles locally.
Born out of a community need in the early 1970s and fostered through a labor of love with support from Park staff and volunteers since, the Sea Life Park Seabird Rehabilitation Facility has been helping native seabird populations and educating the public on the signs to look for in distressed seabirds. Federally protected Wedge-tailed and Newell’s shearwater chicks are particularly vulnerable following breeding season, and the Park assists hundreds of seabirds during these peak months alone with a highly successful release. The facility is equipped to receive injured seabirds 24 hours a day, seven days a week, and is the primary rehabilitation facility on Oahu. In one season alone; Sea Life Park Hawaii took in, rehabilitated, and released over 800 sea birds and since 2005, over 4,000 seabirds have been rescued and released. Birds that are unable to be released are provided a home at the Park’s Seabird Sanctuary.
In the heart of the Sea Life Park campus is the Seabird Sanctuary. In this enclosure of about 500 square feet, you will find a place of refuge for injured Hawaiian seabirds that, according to U.S. Fish and Wildlife Service (USFWS), are not able to be returned to the wild. Here they can live out the remainder of their lives, well cared for and protected in this sanctuary. The program, the only one of its kind in that state of Hawaii, is funded entirely by Sea Life Park. The Park is one of the only facilities on Oahu that operates 24 hours a day every day of the year to care for and rehabilitate injured sea birds (approximately 30-40 a day).
Many of the injuries are caused by cats, mongoose, or marine debris like fishing lines, hooks, or nets. Once the bird is deemed ready, they are released back into the wild. If they are deemed un-releasable they are brought up to our sanctuary. Birds in our sanctuary all have permanent injuries which would make them very vulnerable in the wild, so they stay here to have the longest life possible.
What Makes a Seabird a Seabird?
“Seabird” is a general term used to describe birds that spend most of their lives on the ocean. Birds that are considered as types of seabirds include penguins, albatrosses, petrels, shearwaters, cormorants, gannets, boobies, gulls, and terns. Hawaii is home to 22 species of seabirds. These include the Black-footed Albatross, Hawaiian Petrel, Laysan Albatross, Newell’s Shearwater, along with many more. When looking at the anatomy of these different birds, we can see similarities that all these different species share.
Feather color: Most seabirds have feathers that are dark above and light below. This type of coloration, called countershading, camouflages them from predators in the sky, and hides the bird from prey beneath them.
Feathers: Seabirds have more feathers relative to their body size than other birds, which help them keep warm and stay dry.
Feet: Most seabirds have flexible webbed feet that help them be powerful swimmers. Some species even have strong claws on their feet to help with fishing.
Wing Shape: Seabirds' wings are specially shaped for their unique flight needs. Longer, more tapered wings allow seabirds to soar for hours with very little effort; which allows them to remain far from land.
Salt Glands: Many seabirds have special salt glands that remove salt from the birds' food and water, allowing them to eat and drink without absorbing too much salt. The salt that has been removed is then excreted out of a hole near the bird’s nostrils.
Head Structure: In order to be able to dive directly into the water, seabirds that hunt deeper in the water have different skull features. These features include strong, tapered bills, air sacs and thicker bones.
Nesting behavior: Even though most of their lives are spent at sea, all seabirds return to land to breed. Seabirds are unique in their nesting habits. Nesting sites of seabirds include extreme habitats such as Antarctic icebergs, the tops of mountains, tundra, and remote islands. Petrels and shearwaters may variously nest in simple scrapes on the ground, on cliff ledges, in a burrow or in a rocky crevice.The red-footed booby nests in trees and shrubs. The Albatross prefers to nest in holes on the ground where nest material is available, and build large bowl-shaped nests of grass and mud. Terns are famous for laying their eggs in the forks of small thin branches without using a nest. Some seabirds nest in large groups called colonies. Unlike land birds, parental duties are shared by both parents.
Each year we have what is called a shearwater season where hundreds of fledging shearwaters are disorientated by lights at night, have trouble finding food, or are attacked by cats, dogs, or mongoose. The season runs from November to the beginning of January. People will find the birds and bring them to us to be rehabilitated. Shearwaters make a low crying sound, and are often called the moaning bird. Shearwaters make burrows on the ground and in bushes. They are commonly found on the off shore islands surrounding Oahu.
Red Footed Booby
They are easily identified by their red feet and blue beak. They nest in trees and shrubs.They are plunge divers, which is why they have long sharp beaks.
Brown Booby birds are slightly larger than the Red Footed Booby.They can usually be spotted off the coast of Waikiki and Kaneohe.
The Great Frigates are sexually dimorphic, meaning you can tell whether it’s a male or female just by looking at it. The males are all black with a red inflatable throat pouch. The females are black with white chests. They have a 6 foot wing span. Their Hawaiian name is ‘Iwa which means thief. They get this name because they harass other birds into regurgitating their food and then they steal it. They lack the webbing on their feet, so they cannot land in the water and then take off for flight.
Conservation and the Seabird Sanctuary
We can all do our part to help out these birds in the wild by following the three R’s, reduce, reuse, and recycle. Each year, an estimated 5 tons of plastic is being fed to sea bird chicks that the parents mistook for floating fish eggs or squid.
On the island of Oahu, there are special places that are only reserved for seabird nesting sites. One is “Rabbit Island” right across the road from here. Ka`ena point is another area on the island that is a protected area for seabird nesting. The birds that primarily nest here are the Laysan Albatross and Wedge-tailed Shearwater. Birds can live here and make nests without being disturbed by people.
Albatross are colonial breeders and usually return to the same site/nest every year. One example is a well-known albatross named Wisdom. She is the oldest known bird in the wild, estimated to be at least 66 years old. She has been spotted at the same nesting site since 1956. We generally take in 300 to 800 seabirds a year. We are usually able to release 75 to 85 percent of the birds back into the wild.
Cartilaginous vs. Bony fish
What kind of an animal is humuhumu? It’s a fish! What about a shark? Or a ray? They are, in fact, ALL FISHES! But sharks and rays are a special type of fish. The biggest difference between the sharks and rays and fish is their skeleton. A fish has a skeleton of bone while sharks and rays have a skeleton made of CARTILAGE. Cartilage is a flexible yet tough material that provides support for the body.
Chondrichthys’ (sharks and rays) teeth
There are actually more than 350 species of sharks. Tiger Sharks and Great White Sharks are two types of sharks found around the Hawaiian Islands and their teeth are specially formulated for their prey type-fish, sea turtles, marine mammals, invertebrates, etc. You can actually tell what kinds of things sharks like to eat by looking at a shark’s teeth. Mako Sharks have large, longer, pointed teeth for grabby slippery prey like fish or octopus but Nurse sharks have small, flat teeth that are used to crush hard shells of crabs and lobsters. Tiger Sharks have large, triangular, serrated teeth that almost look like knives. They eat larger animals, and they use their sharp, knife-like teeth to cut and tear their food. Stingrays also have flattened teeth to crush hard things like crabs.
Sharks and rays are able to replace their teeth. Our baby teeth fall out and get replaced by adult teeth, but once you get those, you’re done replacing teeth. Sharks have these rows of teeth that are ready to replace the front teeth. If a tiger shark went to attack its prey, and in the process, lost some teeth, the teeth in the back will then come to the front, like a conveyor belt, to replace the lost teeth. Sharks can replace about 10,000 teeth in a lifetime! Sometimes sharks lose teeth and we find them and make them into a necklace, but the ancient Hawaiians used to use them to make weapons like this one seen here.
Sharks come in all different shapes and sizes. The Dwarf Lantern Shark is the smallest shark, which only grows to be the length of a pencil. The Tiger Shark and the Great White Shark, on the other hand, are both very large fish. However, they are not the largest. This title goes to the Whale Shark. The Whale Shark is as large as a school bus. You may think that a shark that big would have rows and rows of enormous teeth, but they don’t. They’re as gentle as can be and don’t even eat large fish. They are filter feeders, which means that they swim through the water with their mouth wide open and eat the small animals that get stuck on its gill plates when it filters out water.
Sharks are sometimes called the ‘perfect hunters’. This is for a good reason; sharks have been around the earth since the time of the dinosaurs and have not changed too much. They are highly adapted to their life and have many different things that help them to survive. Some sharks sense of smell is so strong that it can smell one drop of blood in a large (Olympic sized) pool. They also have a sense organ in a line along their body called the LATERAL LINE (point to it on either a picture or use the bony fish skeleton) that they use to feel movement or vibration in the water. The body and heart releases very weak electricity. Sharks are also able to feel electrical charge through their AMPULLAE OF LORENZINI so they are able to find fish who have hidden themselves below the sand.
Sharks have something called a nictitating membrane. We have eyelids to help keep our eyes moist. Since sharks live in the water, their eyes are always moist. So they have these “eyelids” to protect their eyes. Right when they are about to attack their prey, they cover their eyes for protection.
They have nostrils which they use to smell in the water. And they have a mouth with lots of teeth. Shark eats fish, squid, crabs, etc. There are many different types of sharks in the world, and they eat different things in the ocean including other sharks. Because of this, the jaws of our sharks are very different in size as well as the shape of their teeth.
Sharks use their gills to breathe oxygen from the water. Most sharks have 5 gill slits but there are few that 6 or 7 gill slits. The dorsal fin of a shark helps it to keep balance in the water just like a dolphin. The bodies of most sharks are usually a mixture of a light color on the bottom and a darker color on the top. This is a form of camouflage called COUNTER-SHADING. When looking up from under the shark, their light underside will blend in with the bright ocean surface lit by the sunlight. When looking down from above the shark, the dark top side of the shark will blend in with the deep dark ocean bottom. A sharks skin can feel rough. Their skin is actually made up of tiny modified teeth-like scales called DERMAL DENTICLES. This shape helps the shark swim fast and smooth through the water. If you were to pet the shark from head to tail, it would feel smooth. But if you went the opposite way, it would feel very rough. Some sharks have different tail shapes, but most of them have a similar forked shape with the top being larger or longer than the bottom.
Some rays flap their fins like wings while others move their fins in a wave like a Hawaiian Brown Stingray. Stingray’s have a spine on their tail which is how they got their name. A stingray uses its spine not for hunting but for protection. Most stingrays spend their lives along the ocean floor and are also very well hidden in the sand/rocks. When something comes near it and threatens it, they may whip their tail to scare it away.
If you look at the underside of the stingray, you will see that their gills are there. Many times you will see stingrays lying motionless on the sea floor so in order to breathe, they have an opening called a SPIRACLE behind their eyes which allows water to flow down over their gills. This is a really cool adaptation they have to help them live on the ocean floor.
A lot of marine animals, including our sharks and rays, are falling victim to something called “Marine Debris”. This is just a fancy word for trash that is found in the ocean. “Marine Debris" is rubbish left behind by people and it can be very dangerous to animals. It could be left on the beach when people go swimming or fishing. But trash left on the side of the street or even up in the mountains can find its way down into the ocean by catching a ride on the wind or flowing down a river. Trash left anywhere can eventually make its way into the ocean. It is a very big problem but there is a very easy solution. To help, you can pick up rubbish and throw it in the trash can. You can also reduce, reuse, and recycle things and make new products out of what was once trash. If we all can do this, our ocean friends, like our sharks and rays, will be much safer.
Did you know that not all penguins live in the ice and snow? Contrary to popular belief, all 17 species of penguins are found in the Southern Hemisphere and only two species, the Emperor and the Adele penguin, live exclusively on the continent of Antarctica. The others are found in places such as Australia, New Zealand, South America, and Africa.
At Sea Life Park Hawaii you can see Humboldt Penguins. These penguins are found in Chile and Peru. They get their name from the Humboldt Current, which flows up from Antarctica along the coast of South America. So the warm Hawaiian weather is actually quite comfortable for them, and if they ever need to cool off they can always take a swim.
The water in the penguin habitat is salt water – penguins are actually a type of seabird! Sea Life Park Hawaii pumps about 12 million gallons of fresh sea water through our habitats every day. We do not put any kind of chemicals into that water, so algae grows naturally in our habitats. This algae called diatoms actually absorb harmful sunlight and produce atmospheric oxygen.
Penguins are birds however they cannot fly. They have many adaptations for swimming and survival in the water. Their wings are shaped like paddles, which enables them to swim up to speeds of 9 miles per hour. They can also dive about 1 to 2 meters deep, and hold their breath for about 1 minute. However, the deepest penguin dive was recorded at 1, 752 feet.
Why are penguins black and white? A penguins coloration is actually a type of camouflage called counter-shading. The back is black because looking down through the water the dark color blends in with the dark colors of the ocean, and the front is white because if a predator was looking up, the penguin would blend in with the light from the sun reflecting on the water.
Thermoregulation: Not only are the feathers colored as camouflage, but they are so tightly packed together, with 70 feathers per square inch or the size of a quarter; that they serve as a waterproof wet suit. This allows the penguins to stay warm in the cold water. The feathers overlap and are coated with oil to make a waterproof dive suit for the penguin. Blubber also provides insulation and energy storage. Despite all of those feathers, penguins go through a yearly molt. During that time, they lose all their feathers and cannot go in the water, therefore they do not feed. The molt occurs at the end of every summer or early fall right after the breeding season. After the molt they get a new soft coat of feathers. This yearly routine occurs throughout the penguin’s entire life, which is about 20 to 30 years in the wild.
Breathing air: When swimming long distances, the penguin breathes by “porpoising,” swimming like dolphins close to the surface with quick leaps into the air to catch a breath. When chasing prey, they surface every 2-3 minutes, but the emperor has been timed at 18 minutes underwater.
Legs: The legs of a penguin help steer, acting as rudders. Just like most other seabirds, their feet are webbed.
Eyes: The penguin is believed to have very powerful eye muscles. This allows it to see prey more clearly by pulling the blurred underwater images together, as in the use of a face mask when a person is snorkeling or diving.
Mouth: A spiny tongue, powerful jaws, and razor-sharp beak aid the penguin in capturing its prey. Food includes fish, crustaceans, (especially krill), and squid. Penguins swallow their food whole, without chewing.
Salt-Excreting Gland: Penguins get water from the foods they eat and by drinking saltwater. Special glands extract excess salt from their blood. The salt solution is expelled from the nose. Droplets flow down grooves on the bill, and then are shaken off.
Penguins have many predators such as seals, sea lions, killer whales, and sharks. However, the most dangerous time for a penguin is while still in the egg and as a chick. Other birds prey on young chicks and eggs. For the penguins living in South America, like the Humboldt Penguin, their eggs are a food source for snakes, lizards, and mongoose. On top of all of these, penguins must survive their biggest threats; which are pollution, habitat destruction, and over fishing. All of which are caused by humans. Only one species of penguin is labeled endangered as of right now, which is the yellow-eyed penguin in New Zealand. However, 4 species, including the Humboldt Penguin are considered threatened.
Seals, along with Seal Lions, and the Walrus; belong to the family called Pinnipeds.
Historically, there were three different species of monk seals in the world consisting of the Mediterranean, Caribbean, and Hawaiian monk seals. The Caribbean monk seal was declared extinct in 1996 with the last sighting of this species in 1952. Today, the status of the Mediterranean monk seal is critically endangered with less than 500 left (NOAA) and the Hawaiian monk seal is listed as endangered about 1,400 individuals remaining here in the islands (NOAA). The Hawaiian monk seal is commonly found along the Hawaiian island chain with the majority of the population located along the Northwestern Hawaiian Islands.
Some of the biggest threats to the Hawaiian monk seals today are shark attacks on juveniles, limited foraging success or starvation due in part to over fishing, marine debris (entanglement and ingestion), male mobbing of females; in this unusual behavior the male seals will “gang up” and kill females and young seals for no apparent reason, human disturbance such as harassing, feeding, boats, fishing hooks and others.
Whats the difference between seals and sea lions? There are a few key characteristics that make seals different from sea lions. First of all, seals do not have ear flaps; they only have small holes for ears. Also seals use their hind flippers to propel themselves through the water and their front flippers to steer; with sea lions, it is the opposite. Also seals cannot prop themselves up on those front flippers, so they can only haul around on land like an inchworm. Pinniped means fin, or flipper, footed. All Pinnipeds are Mammals.
What are the characteristics of a mammal?
Breathe air: Monk seals breath in the opposite way that humans do. Our nostrils are naturally open, and we don’t have the ability to close them. Monk seal’s nostrils are naturally closed, and she has to use muscles to open them to breathe. This is because monk seals spends most of her time in the water.
Hair/fur: Their fur helps to keep them warm. You may notice that sometimes monk seals have green growing on their fur. This is algae! It grows naturally on monk seals in the ocean. Each year, monk seals shed the top layer of their skin along with their old fur coats in a catastrophic molt. This lasts approximately two weeks (NOAA). During the molting process the old layer of fur and skin begins to peel off, revealing a nice new fur coat underneath. A freshly molted monk seal will have a light black and gray top coat, and a beautiful silvery belly. This habitat, like all of our habitats at Sea Life Park Hawaii, contains real ocean water. Sea Life Park Hawaii pumps about 12 million gallons of fresh sea water through our habitats every day. We do not put any kind of chemicals into that water, so algae grows naturally in our habitats. These algae called diatoms actually absorb harmful sunlight and produce atmospheric oxygen.
Warm Blooded: A warm blooded animal maintains a constant body temperature, unlike cold blooded animals that use the environment to maintain their body temperature.
Live Birth: Seals and sea lions give birth to live pups.
Drink Milk. Sea lions and seals also have blubber that helps keep them warm besides their fur. In order to build up their blubber quickly, a monk seal’s milk needs to contain a lot of fat.
Male monk seals typically weigh between 400-500 pounds. Female monk seals generally weigh 400-450 pounds, but can reach up to 600 pounds during pregnancy. The gestation period is approximately one year, and occurs on average every other year starting at 7-10 years of age. Pups are born on the beach with the mother staying with the pup for approximately 5-6 weeks in order to nurse. During the nursing period, the mother will not leave the pup to eat and eventually will lose up to 50% of her body weight; and the pup will gain about 4 times its original birth weight, reaching a weight of approximately 140 pounds. After the 5-6 week nursing period the mother will return to the sea to find food and leave the pup to fend for itself. During the weaning process, the pup must learn to catch its own prey, and the pup will steadily lose weight only about 100 pounds around 1 year of age.
Hawaiian monk seals are opportunistic feeders, so they go after whatever is easiest and most available for them to catch. Their prey includes a variety of fish, crustaceans, eels, octopus and shellfish; all of which are found close to the sea floor. Monk seals do not chew their food like we do, instead they swallow their food whole! Monk seals have 32 teeth and an extremely strong jaw that they can use to crush the bones and shells of their prey. Finding food is one of the monk seals greatest challenges, and sometimes they may have to dive to great depths to find their next meal. The greatest recorded dive depth was 543 meters, or 1781.5 feet, which was documented by video from a small submersible submarine. While diving and foraging, monk seals have the ability to stay underwater for up to 25 minutes with the average dive being 6-7 minutes.
How did monk seals get their name? It is from their fur coat that many believe the monk seal got its name. It is believed that the monk seals fur around its face mimicked the look of a monk’s robe. Another possible origin for the name is that the seals lead solitary lives, much like monks do.
When it comes to animal trainging, we use a technique called “operant conditioning”. This training method enables us to train the animals to undergo numerous medical and husbandry behaviors. These behaviors provide us with a method of closely monitoring her health status, thereby providing optimal care. These behaviors allow us to collect blood samples, body weight measurements, and complete physical inspections of the body, mouth and eyes.
Since the Hawaiian monk seal is an endangered species, they are federally protected under the endangered species act. It is considered a federal offense to touch, feed, or harass a monk seal in any way; doing so could result in fines. Monk seals spend a lot of time on the beach basking in the sun. They will do this to rest, escape a predator, warm up, or get ready to give birth to their pups. If you ever happen to come across a seal on the beach, you want to make sure that you keep your distance giving them plenty of space. Another way that you can help to preserve this species is by making sure you never litter, and always remember to reduce, reuse, and recycle!
The Park has assisted endangered Hawaiian monk seals through an important program that brought in underweight or abandoned seals from the wild and rehabilitated them. Those crucial efforts—along with the impact of NOAA’s Hawaiian Monk Seal Recovery Plan and the work of other key agencies coming together to make a difference—are encouraging Monk Seal population growth.
“Lambchop” was a Hawaiian Monk Seal who resided at the park and passed away at age 32, following a sudden decline in her health from age-related kidney disease. Lambchop was brought to the Park extremely emaciated from the French Frigate Shoals in the Northwestern Hawaiian Islands in 1987. She was estimated to be about two years of age on her arrival, and was rehabilitated back to health under the Park’s care. The average life expectancy of a Hawaiian monk seal is 25-30 years. Lambchop was able to live a full life making many significant contributions that are helping the endangered monk seal population.
Over the years, Lambchop was involved in groundbreaking research—including important studies to measure monk seal metabolism and discoveries that would lead to the development of the morbillivirus vaccine currently being utilized on wild-populations. Morbillivirus is widespread and outbreaks of the disease have caused the deaths of tens of thousands of seals worldwide since the 1980’s. Due to Lambchop having access to 24-hour veterinarian care at the Park, we were able to conduct a cataract surgery resulting in the improvement of Lambchop’s eyesight; and through our daily physical exams, and husbandry training we have recorded that her vision continued to improve. She was able to benefit from procedures previously unheard of for her species, resulting not only in the improvement of Lambchop’s own quality of life but also breakthroughs in the care possibilities for other monk seals.
What is a cetacean? A cetacean is a mammal that spends its entire life underwater such as whales, dolphins, and porpoises. But what makes a cetacean different from a fish is that cetaceans have skin, whereas most fish have scales. Also, cetaceans have lungs so they breathe air, unlike fish who have gills to catch the oxygen out of the water. Fish move their tails from side to side while cetaceans move their tails up and down to propel themselves forward.
Cetaceans are mammals
They breathe air like you and I. All cetaceans have a pair of lungs that lead up to their blowhole(s) on the top of their head that they use to expel carbon dioxide and uptake oxygen from the air. Cetaceans have hair! Some cetaceans have hair on their heads as fetuses, but they don't always keep it. One great example is the humpback whale, which has golf ball-sized bumps on its head that contain hair follicles. Other examples include the right whale, which has hairs on its chin and upper jaw, and the bowhead whale, which has hairs on its lips, chin, snout and behind its blowhole. Cetaceans also give live birth and nurse their calves. An average gestation period for most cetaceans is about a year, followed by 2-3 years of nursing their calf. The last characteristic of a mammal is that it is warm-blooded. They can regulate their body at a stable temperature no matter what the temperature of their environment. So whether they’re in the cold arctic waters of northern Russia, or warm tropical waters of Hawaii, their body is always regulating to around 98.6 degrees. Cetaceans can do this in a variety of ways. Most whales have a layer of blubber (fat) surrounding their body that works as an insulator in colder water. On the flip side, appendages such as fins and flippers have a large surface area to allow heat to leave the body at a faster rate to cool off in warmer waters.
There are many adaptations that cetaceans have to allow them to survive underwater. They have a torpedo-like shape that allows them to streamline through the water, as well as a dorsal fin, pectorals flippers, and caudal fin to help keep balance, steer, and propel them through the water. Some cetaceans, such as Killer whales and Atlantic bottlenose dolphins use a form of camouflage called counter-shading to hide from their prey and predators. If a predator or prey is swimming below them and looks up, the white belly of cetaceans will blend in with the clouds and sky above; now if that predator or prey is swimming below them and looked down the black or darker back would blend in with the ocean floor below. One last unique adaptation that toothed-cetaceans have is called echolocation. To locate food in the open ocean, toothed-whales such as dolphins, Beluga whales, and Killer whales will send air from their lungs through the blowhole and out of their forehead via a cone-shaped beam. That beam will hit an object and return and echo back to the lower jaw that is then sent to the brain to be processed.
There are two different types of cetaceans. The first are the toothed-whales, called Odontocetes. These cetaceans have cone or spade shaped teeth that they use to capture their prey and swallow them whole. The next type is the baleen whales, called Mysticetes. These cetaceans have thick hair/brush-like teeth called baleen that they use to filter out small animals from the water column. In the wild, toothed whales (such as the Orca) tend to be smaller than baleen whales (such as the Blue whale). Also, all toothed whales have one blow hole on the top of their head whereas all baleen whales have two blow holes! So if you’re ever in a boat or helicopter looking at a cetacean from above count the blow holes and that will tell you whether the whale has cone shaped teeth or baleen. Baleen is made out of keratin, which is the same substance found in human finger nails and hair! There are many of species of whales that have baleen such as the massive Blue whale, the Right whale, and the Humpback whale.
There are different methods and forms of feeding that they do, such as bubble netting and gulp-feeding (shown here). Bubble netting is just what it sounds like, where a group of humpbacks will dive down to schools of krill where one whale (the bubble-blower) will release a ring of bubbles from its blowhole as it spiral beneath the prey. As this air rises to the surface, it creates a curtain of bubbles that acts as a physical barrier to frighten and retain the krill. Simultaneously, another whale in the group will produce vocalizations, which also act to frighten the prey and trigger them to school up in tight balls within the bubble net. The whales then lunge, mouths open, to the surface through the center of the bubble ring, or bubble net. This motion drives the krill to the surface, where they are trapped from all sides and allows the humpback to open its mouth and sieve the krill through its baleen.
What is the difference between a dolphin and a porpoise? Dolphins have cone-shaped teeth and a long, pointed rostrum (snout) whereas porpoises have spade shaped teeth and short, blunt rostrums. Some other physical differences are that dolphins have a curved dorsal fin and can be up to 12 feet long! Porpoises have a straight dorsal fin and can only reach lengths of 7 feet long. Dolphins are also very social, playful animals that live in large pods and use audible sounds to communicate with one another; but on the flip side porpoises are shy and live in smaller pods and use inaudible ways of communicating.
Each cetacean has their own unique fingerprint on their fluke (tail). No two flukes look exactly a like because they each have different color patterns and shapes, and that helps us distinguish between different cetaceans in the wild. Did you know that different cetaceans make different vocals? Some, like the Humpback whale even sing!
Do cetaceans sleep? Well dolphins and whales have to sleep slightly different than you and I because they are voluntary breathers, which means their brain has to actively think about taking a breath. That’s different than you or I because we don’t have to constantly be telling our brains to breathe. So when cetaceans sleep they have to rest by using one half of their brain at a time so that they are always breathing.
Bottlenose dolphins are the most well recognized species of dolphin because of their roles they have played in television shows, movies, and aquariums. They are very intelligent and fun animals and do a variety of behaviors such as tail slapping, breaching, chasing one another, using sea-weed and sponges as tools, and comprehending language. A bottlenose dolphin’s life expectancy is 40-50 years and their average size is 6-12.5 feet long and 300-1400 pounds. Dolphins also eat a variety of different animals such as fish, invertebrates, shrimp, and other crustaceans. Here at the park we feed our dolphins Herring, squid, and capelin.
Sea Life Park has 15 bottlenose dolphins total including both Atlantic and Pacific bottlenose dolphins. Atlantic bottlenose dolphins are from the Atlantic Ocean and are smaller, a lighter shade of grey, and have a more triangular dorsal fin whereas Pacific bottlenose dolphins live in the Pacific Ocean and are larger, darker, and have a more curved dorsal fin. Here at Sea Life Park in the Dolphin Lagoon we also have the one and only Wholphin! Her name is Kekaimalu, which means “the peaceful sea”, and she is what we call a hybrid species meaning that she is a mixture of two different types of cetaceans, her mom is a bottlenose dolphin, and her dad is a false killer whale! Kekaimalu was born 1985 which makes her over 34 years old. What is very interesting is that some parts of her looks like a bottlenose dolphin and some parts look like a false killer whale. Her skin is dark grey, so not exactly jet black like her father and not light grey like her mother. Kekaimalu also had a calf in 2005 that lives at the Dolphin Lagoon and is ¾ Atlantic bottlenose dolphin and ¼ false killer whale named Kawili Kai.
Bottlenose dolphins are not fish; they are mammals like you and I. There are 5 main characteristics that make them mammals. They are warm blooded. This means that they can regulate their body temperature to a stable 99 degrees Fahrenheit. Just like you and I, no matter what the temperature is outside, our bodies stay at a stable temperature. The second characteristic is that dolphin’s breathe air with their lungs through their blowhole which is located on the top of their head. Dolphins can hold their breath for an average of 7 to 8 minutes. Bottlenose dolphins also give birth to one calf about every 3 years, and the calf will nurse from its mother for 2-3 years before it ventures out on its own. Dolphins’ milk is very rich and is 33% fat! They need this in order to build their blubber, or fat layer. Since the ocean water can get cold, they need this blubber layer to keep themselves warm. Lastly, when they are born, dolphins have small hairs on their rostrum (upper jaw and nose) that will fall out as they age.
The dorsal fin of a bottlenose dolphin is located on the dolphin’s back and is used for stability, to release excess heat from the body, and to identify different dolphin’s out in the wild. The dorsal fin is easily scarred and comes in a variety of shapes and sizes based on the type of dolphin so that is how it is used to identify different dolphins in the wild. The back fin, or the fluke, is a strong muscular tail used for powerful upward strokes and forward motion. Now both of these fins are filled with connective tissue, but the pectoral flippers, which are located on the side of the dolphin and are used for steering, have bones similar to our arm, wrist, and hand. A dolphin’s eyes are well-developed and are placed on the side of the head for 360 degree vision. They have an elongated nose, called the “rostrum” with an upper and lower jaw that contain 88 cone-shaped teeth. Dolphins have a blowhole that is directly connected to the lungs. This respiratory system is 63% more effective than a human, which allows them to dive to deeper depths. Their airway and feeding tubes are completely separate, so dolphins do not have a gag reflex like humans do.
Echolocation. To locate food in the open ocean, dolphins will send air from the lungs through the blowhole and out of their forehead (that is filled with fats) via a cone-shaped beam. That beam will hit an object and return and echo back to the dolphin’s lower jaw (also filled with fats) that is sent to the dolphin’s brain to be processed. This is an amazing adaptation, and all toothed-whales, such as Killer Whales and Beluga Whales, use this to locate their food.
Besides using echolocation, and having very efficient temperature regulation and respiratory systems, dolphins also have a few more adaptations that allow them to thrive underwater. (Bring out rubber skin) Dolphin’s have a torpedo-shaped body and sleek skin, such as this rubber sample, that allows them to swim more efficiently. Their backs are a darker grey whereas their bellies are white. This is a form of camouflage called "counter-shading" that allows them to hide from predators by blending in with the ocean floor as well as the sky above.
Out in the ocean, Killer whales and some species of sharks such as Tiger sharks and Great White sharks will prey on dolphins but the number one predator of any marine species are humans! Dolphins are accidentally caught in fishing nets, run over by boats, and confused by underwater sonar; but a major issue affecting all marine species right now is marine debris. Marine debris is just a fancy word for our trash ending up in the oceans and it kills over 100,000 marine species a year! Even though it is a major issue there are many things that you can do to help prevent the endangerment of dolphins as well as other marine animals. The first thing you can do to help is by educating yourself so you can also educate your family and friends. Get involved in beach clean ups with your community as well as know your local communities laws and regulations put into place for protecting marine animals! Even if you don’t live by a beach, cleaning up trash and recycling your plastics helps in a major way worldwide. Practice the 3 R's-Reduce, Reuse, and Recycle, and refrain from swimming with or feeding a dolphin out in the wild. This can lead a wild animal to become too comfortable to humans which can be harmful to their safety and to yours.
Sea Lions, along with Seals, and the Walrus belong to the family called Pinnipeds. Pinniped means fin, or flipper, footed.
Although commonly confused for one another, there are many differences between seals and sea lions. Sea lions have large fore, or front, flippers that when on land are used to push themselves up off of the ground. These fore flippers paired with their rotating hind, or back, flippers are what allow sea lions to be able to move around easily in a walking like motion. Seals on the other hand, have short thinly webbed fore flippers that cannot support their body weight; and hind flippers that point away from their bodies and do not have the ability to rotate. This limits seals to hauling while they are on land, which looks much like a very large caterpillar. Although the ears of seals and sea lions appear different, both of these animals have a keen sense of hearing. Sea lions can be identified by their external ear flaps, while seals have tiny holes that are harder to see on each side of their head.
All Pinnipeds are Mammals. There are 5 mammal characteristics.
1. Breathe air: If you look at a Pinniped’s nostrils, you will notice that it is opposite from human’s nostrils. Our nostrils are naturally open, and we don’t have the ability to close them. Pinnipeds nostrils are naturally closed and they have to use muscles to open their nostrils in order to breathe. This is because they spend most of their time in the water.
2. Hair/fur: Their fur helps to keep them warm. Sea lions and seals molt, or shed their skin, once a year. When molting these animals will lose almost all of their fur, and grow a brand new shiny coat. Before molting their fur may appear to have a green tint, this is algae that sometimes get caught in between the hairs. The California Sea Lion habitat contains real ocean water. Sea Life Park pumps about 12 million gallons of fresh sea water through our habitats every day. We do not put any kind of chemicals into that water, so algae grow naturally in our habitats. These algae called diatoms actually absorb harmful sunlight and produce atmospheric oxygen.
3. Warm Blooded: A warm blooded animal maintains a constant body temperature; unlike cold blooded animals that use the environment to maintain their body temperature.
4. Live Birth: Seals and sea lions give birth to live pups. Females and pups communicate using vocalizations that are unique to the female and pup. Each pup and female has a unique scent that also identifies them.
5. Drink Milk: Sea lions and seals utilize their blubber to help keep them warm besides their fur. In order to build up their blubber quickly, Pinniped’s milk needs to contain a lot of fat. A sea lion’s milk contains 33% fat.
California sea lions are found from Vancouver Island, British Columbia to the southern tip of Baja California in Mexico. Their population is growing steadily, and California sea lions can be seen in many coastal spots such as Seal Rock or PIER 39 in San Francisco. Unlike most seals who tend to live solitary lives, sea lions are more social animals and are known to congregate in groups.
California Sea Lions are sexually dimorphic, which means you can tell the difference between the males and females just by looking at them. Males are larger than females. Males may weigh up to almost 900 pounds and females may weigh up to almost 300 pounds. Males also have a much more pronounced forehead, known as their sagittal crest. California sea lion males bark like a dog to communicate with other males and females.
The vocalization of seals and sea lions are also very different. Sea lions are known to be quite noisy, and can even project loud barks. However, seals are known to be much quieter; in which they vocalize by using softer grunt and growl like noises.
California sea lions feed on fish and squid near the ocean surface, but can dive to depths greater than 500 feet. Their dives are usually about 3 to 5 minutes long, but sea lions may be able to stay underwater for about 15 minutes. Our California sea lions here at Sea Life Park Hawaii are fed high quality fish which includes capelin and herring.
We train our sea lions by using positive reinforcement. The animals at Sea Life Park Hawaii are trained for husbandry, which are medical behaviors that are used to better ensure that are animals are always in good health.
The California Sea Lion is protected under the Marine Mammal Protection Act of 1972, but threats do include bycatch and entanglement in fishing gear, biotoxins from large algae blooms, and human-caused injuries. According to the National Oceanic and Atmospheric Administration (NOAA), there has been an Unusual Mortality Event declared in California. Since January 2013, there have been a high number of sea lion pups and yearlings stranding on the beaches in southern California. NOAA is still investigating the situation, but has stated that their evidence has shown that this event was not caused by a single infectious disease. Many organizations are hypothesizing that this event has been caused by the lack of food due to unusually warm water in the area. Some say that the mothers of the malnourished pups are foraging for food for extended periods of time; in which they are spending too much time away from their pups, and this is causing the pups to flee and fend for themselves. The Stranding Network rehabilitation facilities in the area are banning together to help take in and rehabilitate the stranded pups, and according to NOAA there is over a 50% survival rate. The pups being released are fitted with satellite tags, and the data from those tags show that those animals are surviving after their release. Another huge threat to this species is marine debris. They can get entangled in debris such as nets or fishing line; and they can mistake plastic for food, and end up eating the marine debris.
Echinoderms are the group of animals that consists of sea stars, sea urchins, sea cucumbers, brittle stars and crinoids. They are part of the larger group of animals called INVERTEBRATES. We have a backbone and fish have a backbone, but sea stars and their cousins DO NOT have bones. Therefore they are referred to as invertebrates. Invertebrate means without a backbone.
Sea stars and their cousins belong to a group called Echinoderms. Echinoderm means spiny skin. If we break the word down echino = spiny and derm= skin, so these animals are spiny-skinned. Sea stars and their cousins are part of a group of spiny-skinned animals.
Sea Stars. Most sea stars have five arms. The underside of each arm holds 2-4 rows of tube feet, or suction cup feet. They use these feet to hold onto and move around on rocks and on the ocean floor.
Brittle stars. Brittle means it’s fragile and breaks easily. The Brittle stars have spiny arms which enable the star to anchor inside holes or crevices. They are very sensitive to light, and are mostly found under rocks and in crevices.
Sea urchins. Their jaws and teeth allow some species to bore directly into rocks. All sea urchins have a hard skeleton made out of calcium, called a test, under their spines. Biologists are able to identify the kind of urchin just by looking at its test.
Sea cucumbers. Sea cucumbers have a mouth on one end of its body. They may look like a worm but they hold a lot of water in their body. When we touch it, it feels soft instead of poky, but it has tiny little spines along its body. Sea cucumbers are like vacuums of the ocean. They suck in the sand, take what nutrients they want, and the sand comes out the other end. They are filter feeders using their tentacles to gather food and bring it into the mouth.
The characteristics Echinoderms have in common are:
1. Pentamerous Radial Symmetry They all have pentamerous radial symmetry. Wow, those are big words. Let’s say it together. Pentamerous Radial Symmetry. Very good.
2. Tube Feet They all have tube feet
3. Regenerate They can all regenerate body parts and tissues.
4. Spiny Skin They all have spiny skin
1. Pentamerous Radial Symmetry
One characteristic of an echinoderm is that they all have pentamerous radial symmetry. This simply means they all have 5 equal body parts. You can divide these animals into five equal parts, and every part is the same. For example, most sea stars have five arms or a multiple of five arms. The sea cucumber, although you may not be able to see it by just looking at it, does have this five part symmetry. If you were to peel it open like a banana, you would see five equal sections. A sea urchin looks round however, if all the spines fell off, its skeleton, or test, would show it has 5 body parts. The sea urchin has five parts just like the brittle star and the sea star.
2. Tube Feet
When we go for a walk we use our feet. Echinoderms have feet too, but they are called tube feet. They have many little tube feet that are like little hoses with suction cups at the end. A feature that is unique to this group is their water vascular system. They have water filled canals that end in the tube feet, enabling this group to anchor themselves to substrate such as rocks and corals. They use their tube feet to attach to rocks, but also for locomotion. All echinoderms have tube feet. Like we mentioned in the introduction, tube feet help the animal to move and hold onto the rocks.
Another characteristic of echinoderms is that they are capable of regeneration. Regeneration means that echinoderms are able to “re-grow” or restore organs, tissues or body parts that are injured or lost. Sea stars for example are able to re-grow a missing arm. The brittle star is a champion when it comes to growing a new arm. Brittle stars like to hide under rocks. They may not realize that one of their arms is sticking out and waving in the ocean. Sometimes, hungry fish come along and grab one of the brittle star’s arms. The brittle star lets the arm break off out of fear for its life, which allows the brittle star to get away from the predator. Even though these animals can re-grow an arm you never want to pull off the arms of these animals. It takes a long time for them to grow back!
4. Spiny Skin
Echinoderm means spiny skin so the last characteristic they all share is….spiny skin. The spines are very obvious in some echinoderms. The sea urchins, for example, have obvious spines covering their body. But for others, like the sea cucumbers, it’s less obvious. Sea cucumbers do, however, have tiny little spines called spicules in the walls of their body that we aren’t able to feel as we touch them.
All echinoderms have mouths. They have to eat just like you and I. Their very tiny mouth is located on the underside of the animal. Usually sea stars eat small pieces of food they find on the ocean bottom. However, their favorite foods are oysters and clams. The mouth of the sea star is on the underside of the body where the base of all the arms meet. The opening is very small, maybe a quarter of an inch wide on a full grown adult. With a mouth so small it seems hard to believe that they could eat anything of very large. There are no mouthparts or claws that could be used to tear flesh into bite-sized chunks. You would look at this animal and think even if it managed to capture its prey, there is simply no way it could get the food into the stomach. Which is true, so rather than bring the food to the stomach, the sea star brings its stomach to the food. Once the prey is captured the jelly-like stomach actually oozes out of the tiny mouth in a process known as eversion. When the everted stomach is outside of the sea star’s body it is literally turned inside out, exposing the digestive enzymes to the prey and partially digesting the meal outside of the body. The liquefied food is then absorbed through the stomach lining and into the body and is transferred to organs in the arms, where the digestive process is completed. When it’s all done feeding, the stomach muscles contract, pulling it back inside the body again. Anything inedible, such as shell fragments or spines are ejected back out of the mouth by muscle contractions. What an amazing adaptation!
What makes a fish a fish?
1. Gills: In order to breathe, we use our lungs to bring oxygen into our bodies. In the same way, fish use gills. The gills take the oxygen out of the water and bring it into the body of the fish.
2. Scales: Scales provide protection for the fish against diseases and infections and some predators. Scales cover the body, overlapping, kind of like shingles on a roof. This provides protection like a flexible suit of armor. The scales also make the fish more slippery and slimy, which makes them more streamlined and difficult to catch. Every fishes scale is unique to that species so, if you were to find some fish scales, you would be able to tell what kind of fish it was, just by examining the scales. You can actually tell the age of a fish by looking at its scales. The concept is similar to counting the rings of a tree trunk to see how old it was. There are rings on the scales of fish which show the growth of the fish, which enable us to estimate the age of the fish.
3. Cold-blooded: Fish are cold-blooded unlike us, mammals. We are warm-blooded, which means that our bodies stay at a constant temperature of about 98.6 degrees. Because fish are cold-blooded, their body temperature changes with their surrounding environment. So, which fish would have the colder body temperature… a fish living in Hawaii, or Alaska? Right, the fish living in Alaska probably would have the colder body temperature because the water is colder.
4. Vertebrate: The presence of a backbone makes an animal a vertebrate. Fish too have backbones so that makes fish vertebrates. Sharks are cartilaginous fish that have backbones made out of cartilage-that tough flexible material that makes up our ears and parts of our nose. Because sharks are cartilaginous, this means that they do not have any bones in their body, except for their jaws.
5. Swim Bladder: The swim bladder of a fish looks like a small balloon which helps the fish to control its buoyancy or ability to float and move up and down within the water. It is able to take air from its bloodstream to fill up the air bladder. This allows the fish to rise. The fish is also able to deflate its swim bladder to sink to deeper depths. Sharks do not have swim bladders however. Many sharks have to constantly swim around and move in order to keep the flow of oxygen running through their gill slits. Other sharks are able to pump water over their gills and rest on the ocean bottom such as the White tip reef shark, the lemon shark and the nurse shark.
6. Fins: All fish have fins. Fins help the fish move through the water. Fins are used for steering and movement.
Eyes: Fish have eyes, which enables them to see well underwater. What do we have that protects our eyes and keep them moist, so they do not dry out-eyelids. Do fish have eyelids? Actually most fish do not have eyelids, but sharks do. They have what is called a nictitating membrane, which is a tough membrane that protects the eyes from the bones and debris that may cut into their eyes as they are feeding.
Nostrils: Also on their heads are their nostrils. For most fish and sharks, smell is the most developed sense. Fish use the sense of smell to detect the scent of a potential mate. Sharks use the sense of smell to detect the scent of potential prey. Sharks are able to detect smells at very low concentrations of about one part scent per ten billion parts of water. That is like being able to smell one single drop of blood in an Olympic sized swimming pool. For this reason, sharks have been nicknamed “swimming noses”.
Mouths: Fish have all different shapes of mouths. Some have large mouths, some very small. For fish, and for most animals, the shape and size of their mouths depend on the type of food they eat. For example, if you noticed the stingray’s mouth is on the bottom of their bodies. This is because they feed on animals living on the ocean floor. The Moorish Idol has a long and small mouth. This is because they feed on sponges that are sometimes found in rock crevices. Sharks usually have very large jaws, with many sharp teeth. There are many rows of teeth, this is because sharks have a special way to replace their teeth. When sharks eat, they thrash around when tearing at their prey, and they are constantly losing teeth. When they lose a tooth, the one right behind it simply moves up in its place. The shape of the tooth is also dependent on the shark’s diet.
Gills: The gills are used to get oxygen out of the water. The fish gills are covered by a bony plate called an operculum. Sharks do not have an operculum, but they do have gill slits. Most sharks have 5 gill slits. Sharks along with stingrays also have a modified gill called a spiracle that is right behind the eyes. The spiracle takes in water for breathing when the mouth is being used for feeding. On stingrays, the gills are on the bottom and the spiracle is on the top. The reason for this is because stingrays are bottom dwellers, and are often buried in the sand and only their spiracles are exposed for breathing, another wonderful adaptation.
Fins: The dorsal fin is used for stability so that the fish isn’t rolling as it swims through the water. Some fish will have spines near their dorsal fin that they use for protection. The pectoral fins are on the side and are used in some, for movement, and also for turning and stopping. Another very important fin is the tail fin or caudal fin. This fin provides power when swimming. Tails of fish are all shaped differently. By looking at a fish’s tail, you can tell what kind of habitat they live in. Fish with the forked tail such as the shark and weke or goatfish, are fast swimmers, and are found in the open ocean. Those fish with the more rounded tails like the Humuhumunukunukuapua’a are slower swimmers and are likely to be found near the reefs where they have more places to hide.
Scales: Scales are overlapping plates that protect the fish. Sharks do not have scales like other fish; they have modified scales called dermal denticles which mean tiny skin teeth. These dermal denticles help to make sharks more efficient swimmers, and also allow them to swim silently through the water compared to other fish that generate quite a bit of noise when swimming through the water. They are better at the sneak attack. If you were to feel a shark from head to tail it would feel smooth, but if you went from tail to head it would feel like sandpaper. When you feel a real fish, it feels slimy. This slime is used for protection, because it makes the fish that much more difficult to catch and hold onto. It also helps to streamline the fish as it swims through the water.
Lateral Line: You may notice that fish have a line running across their body from head to tail. This is called the lateral line. This is a sensory device that enables the fish to detect any movement in the water. This helps the fish find food and avoid predators.
1. Countershading: or having a light underside and dark top allows sharks and some fish to blend into the ocean and sneak up on their prey.
2. Mimicry: Some fish have mimicry colors and are able to make themselves resemble or imitate other species which protects them from unwanted predators.
3. Warning coloration: These are usually bright colors that announce danger to potential predators.
4. Disruptive coloration: These are color patterns break up the shape of the fish and make it difficult for a predator to catch the fish.
As far as body shape there are the fish that are:
1. Fusiform: or torpedo-shaped, is a shape that means streamlined and is typical of fast swimmers like the shark.
2. Compressed: or flat from side to side making the fish look tall and thin aids in short bursts of speed like the butterflyfish.
3. Depressed: which means flattened from top to bottom for flight type swimming such as the stingray.
4. Filiform: or long and skinny for snake like swimming as you can see in the eel.
All of these different body shapes serve a purpose for fish, allowing it to live successfully in its habitat.