1. Starfish aren’t fish! They are echinoderms, invertebrates, and are related to sea urchins and sand dollars.
2. If an arm of a starfish becomes detached, it can grow a new one (though it might take up to a year to grow)!
3. To eat, a starfish spits out its stomach and digests whatever it’s eating (like a mussel or snail) on the outside of its body. Then it sucks back in its stomach to finish digesting.
4. There are 1,600 kinds of starfish in the ocean. They range in color from red, orange, brown (there’s a chocolate chip sea star), purple, yellow and more!
5. The tube feet of a starfish are amazing. They create suction by sucking in seawater. The tube feet help the sea star move, and manipulate its prey.
6. A starfish can live up to 35 years.
7. Starfish are eaten by other sea stars, fish, manta rays and sharks.
8. Not all starfish have 5 arms, some have up to 24 arms, like the sunflower sea star!
9. The crown-of-thorns starfish (COTS) is found in the Indo-Pacific and outbreaks of them cause damage to coral reefs. COTS eat exclusively coral polyps and cause the coral to turn white and die. The COTS cause almost as much damage as coral bleaching, like on the Great Barrier Reef off Australia.
10. Starfish have no brain, no blood and no central nervous system. They can “see” with eyes on the end of their arms. These eyes sense light and dark.
For more facts, visit Nat Geo Kids Starfish Facts
For more on the sunflower sea star, visit Monterey Bay Aquarium Animals A-Z
Ever wonder what kind of sea star Peach from Finding Nemo is? Visit The Real Fish of Finding Nemo
The following are 10 Cool Shark Facts in a question and answer format.
1.How many shark species are there?
There are 512 described and 23 un-described shark species (according to Wikipedia)
2. Are sharks vertebrates?
Yes, sharks are vertebrates. Vertebrates have a backbone or spinal column. In the case of sharks, they have a spinal column made out of cartilage, not bone as in other vertebrates like bony fishes.
2.What is a group of sharks called?
A shoal (this applies to other fish as well)
3. What are baby sharks called?
5. Are sharks endangered?
At least 143 species are on the IUCN red list with 210 more as data deficient (meaning we haven’t studied them closely enough to know how endangered the sharks are). But all sharks are in danger of becoming endangered due to overfishing, pollution, and other threats facing our oceans.
6. How many millions of years old are sharks?
The first sharks appeared 440 million years ago.
7. Which shark is the smallest? Which shark is the largest?
The smallest shark is the dwarf lantern shark, which grows to 7.9 inches (20 cm)
The largest shark is the whale shark, which can grow up to 60 feet (but is found to be 18-33 feet long on average)
8. Are sharks found in freshwater or saltwater?
Most sharks are found in the ocean in saltwater, but the river sharks are found in fresh and brackish water (slightly salty water) in Asia and Australia. The bull shark is unique in that it can live both in fresh and saltwater in tropical rivers worldwide.
9. Do sharks have swim bladders?
No, unlike the bony fishes, sharks don’t have swim bladders but the oil in their livers help them stay afloat.
And the final cool shark fact is:
10. How often do sharks eat?
It varies greatly between shark species. A great white shark can go a month without food after a full meal.
Also see: 10 Not-so-Scary Tiger Shark Facts
10 Interesting Great White Shark Facts
and Great White Shark’s Adventure at the Monterey Bay Aquarium
Fun quiz on sharks from NatGeoKids
10 Sea Cucumber Facts
1. Sea cucumbers are not a vegetable, but an invertebrate (animal without a backbone). They are like a squishy leather-like terrestrial cucumber with a mouth on one end and an anus on the other. They breathe through their anus(!)
2. There are 1,200 known species of sea cucumbers. Sea cucumbers come in many colors, including orange, red, and brown.
3. Sea cucumbers are echinoderms and are related to sea urchins and sea stars.
4. They are abundant on coral reefs, one per square meter on un-fished reefs. Below 15,000 feet (the deep sea), they make up 90 percent of life on the seafloor.
5. Small animals sometimes take refuge in the sea cucumber’s rectum!
6. They average 3-12 inches long, but can be as small as 0.75 inches and as long as 6.5 feet.
7. Sea cucumbers are nocturnal and play an important role on a coral reef. *see more below
8. Sea cucumbers have 2 lines of defense. They can shoot out white sticky threads that tangle up any predator. They also can expel their internal organs, which are then regenerated.
9. The larvae (“baby” sea cucumbers) of sea cucumbers are planktonic and float in the ocean currents. The adults are benthic, which means they live on the seafloor.
And our last sea cucumber fact:
10. A sea cucumber can live 5-10 years (if it doesn’t get eaten or fished out as an Asian delicacy).
*Sea cucumbers are scavengers and ingest sand to eat whatever’s “stuck” to it, much like an earthworm ingesting dirt for food. The sand moves through the sea cucumber’s acidic digestive tract. The acid dissolves calcium carbonate from the sand and it is pooped out into the surrounding seawater. Corals use that calcium carbonate to build their skeletons. Calcium carbonate is alkaline (like an antacid) and can buffer acidic seawater. Scientists are studying if sea cucumbers can help mitigate the negative effects of ocean acidification due to climate change. For more on ocean acidification, see Ollie the Octopus and Ocean Acidification Definition
7 Facts You Didn’t Know About Sea Cucumbers
National Geographic page on Sea Cucumbers
National Wildlife Federation’s Page on Sea Cucumbers
1. The opah, or moonfish, is a fully warm-blooded, deep-diving flat and round fish.
2. The opah has a silvery gray body, red fins and mouth, and white spots all over.
3. Opah average 100 pounds (but can weigh up to 200 pounds) and is the size of an automobile tire-about 3 feet in diameter-but oval shaped.
4. Scientists have discovered recently through DNA testing that there are 5 distinct species of opah.
5. Opah eat fish, krill and squid.
6. Opah dive to depths of 165-1300 feet (50-400 meters).
7. Opah swim using their pectoral (side) fins and swim quickly like tuna.
8. Predators of opah include humans and large sharks such as great white sharks and mako sharks.
9. Scientists have tagged opah and found that they migrate thousands of kilometers.
10. Opah are caught as by-catch—by accident—by the tuna and swordfish fisheries. Off the United States, 30,000 opah were caught by the Hawaiian longline fishery in 2015 and the fishery is worth 3.2 million US dollars.
Also see a similar looking fish, the Mola Mola or Ocean Sunfish: 10 Interesting Facts About the Mola Mola or Ocean Sunfish
Opah, the first warm blooded fish identified: 7 facts you should know about it
1. A polar bear’s skin (under its white fur) is actually black to help keep it warm. A polar bear’s white hairs are hollow to help it float while swimming.
2. A polar bear can growl, roar, chuff, hiss, whimper and purr.
3. An adult polar bear’s paw is the size of a dinner plate. Its footpads have small bumps on them, like those on a basketball, so the polar bear has traction on ice.
4. A sense of smell is a polar bear’s strongest sense. A polar bear can smell seals from several miles away.
5. Polar bears mainly eat ringed seals, but also eat bearded, harp and hooded seals as well as carcasses of beluga whales, walruses, narwhal whales, and bowhead whales.
6. Male polar bears are about 9 feet long (2.7 m) and weigh 1000 pounds (453.6 kg). A female polar bear is 8 feet long (2.4 m) and weigh 500 pounds (226.8 kg) (unless pregnant).
7. In the summer, a polar bear may not eat for 3 months. A mother polar bear won’t eat for 5 months while in a birthing lair. Polar bears do not hibernate.
8. Polar bears can hold their breath for 2 minutes. They doggy paddle with their front paws and steer with their rear paws while swimming.
9. A mother polar bear usually has twin cubs. At birth, cubs are the size of guinea pigs. They emerge from their den 3 months after being born so their mother can feed. They leave their mother after 2.5-3 years.
10. Polar bears can run faster than humans, but only for a few seconds.
Facts from children’s book The Polar Bear by Jenni Desmond