Corals get their vibrant colors from the algae they host.
Photograph courtesy The Coral Kingdom Collection/NOAA
Map
Coral Range
Fast Facts
- Type:
- Invertebrate
- Diet:
- Carnivore
- Average life span in the wild:
- Polyp, 2 years to hundreds of years; colony, 5 years to several centuries
- Size:
- Polyp, 0.25 to 12 in (0.63 to 30.5 cm)
- Group name:
- Colony
- Protection status:
- Endangered
- Did you know?
- Corals are so sensitive to climatic change that scientists study coral reef fossils to construct highly detailed chronologies of prehistoric climate patterns.
- Size relative to a tea cup:
-
Coral organisms, called polyps, can live on their own, but are primarily associated with the spectacularly diverse limestone communities, or reefs, they construct.
Coral polyps are tiny, soft-bodied organisms related to sea anemones and jellyfish. At their base is a hard, protective limestone skeleton called a calicle, which forms the structure of coral reefs. Reefs begin when a polyp attaches itself to a rock on the sea floor, then divides, or buds, into thousands of clones. The polyp calicles connect to one another, creating a colony that acts as a single organism. As colonies grow over hundreds and thousands of years, they join with other colonies and become reefs. Some of the coral reefs on the planet today began growing over 50 million years ago.
Coral polyps are actually translucent animals. Reefs get their wild hues from the billions of colorful zooxanthellae (ZOH-oh-ZAN-thell-ee) algae they host. When stressed by such things as temperature change or pollution, corals will evict their boarders, causing coral bleaching that can kill the colony if the stress is not mitigated.
Corals live in tropical waters throughout the world, generally close to the surface where the sun's rays can reach the algae. While corals get most of their nutrients from the byproducts of the algae's photosynthesis, they also have barbed, venomous tentacles they can stick out, usually at night, to grab zooplankton and even small fish.
Coral reefs teem with life, covering less than one percent of the ocean floor, but supporting about 25 percent of all marine creatures. However, threats to their existence abound, and scientists estimate that human factors—such as pollution, global warming, and sedimentation—could kill 30 percent of the existing reefs in the next 30 years.
Other Reef Dwellers
Invertebrate Features
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Coral
It's reef madness in this colorful gallery of coral formations.
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Photo Gallery: Coral Reefs
About 80 percent of all life on Earth is found in the oceans, which cover 71 percent of the planet's surface. Take a look at how colorful life under the sea can be.
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Lobster
Learn more about these popular crustaceans that some think of only as a meal. Find out the sizes that these sea creatures are capable of attaining.
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Sea Cucumber
Learn how these amazing echinoderms deter predators by snaring them with sticky threads and even hurling their internal organs about.
Animals
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Aardvark
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Adélie Penguin
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African Elephant
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African Lion
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African Wild Dog
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Albatross
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Alligator Snapping Turtle
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Amazon Horned Frog
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American Alligator
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American Bison
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American Bullfrog
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American Crocodile
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Ammonite
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Andean Condor
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Anglerfish
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Ankylosaurus Magniventris
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Ant
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Arabian (Dromedary) Camel
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Arctic Fox
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Arctic Hare
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Arctic Skua
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Armadillo
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Asian Elephant
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Asian Lion
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Atlantic Bluefin Tuna
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Aye-Aye
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Bobcat
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Box Jellyfish
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Brachychampsa Montana
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Brown Bear
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Bull Shark
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Burmese Python
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Butterflyfish
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California Condor
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California Sea Lion
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Canada Goose
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Cane Toad
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Canvasback
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Caribou
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Carolina Wren
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Cheetah
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Chimpanzee
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Chipmunk
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Cicada
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Clouded Leopard
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Clown Anemonefish
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Coelacanth
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Common Earthworm
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Common Loon
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Common Octopus
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Common Sandpiper
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Common Vampire Bat
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Common Wombat
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Coral
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Cottontail Rabbit
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Coyote
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Cretoxyrhina Mantelli
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Cuban Screech Owl
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Cubera Snapper
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Deer Tick
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Devil Frog
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Dingo
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Dog Snapper
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Dolichorhynchops Osborni
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Domestic Cat
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Domestic Dog
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Draco Lizard
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Dugong
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Eastern Coral Snake
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Eastern Diamondback Rattlesnake
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Eastern Gray Kangaroo
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Egyptian Giant Solpugid (Camel Spider)
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Electric Eel
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Elephant Seal
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Elk
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Emperor Penguin
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Fennec Fox
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Firefly (Lightning Bug)
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Flying Fish
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Flying Snake
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Fossa
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Frilled Lizard
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Fur Seal
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Galápagos Tortoise
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Gelada
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Gentoo Penguin
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Geographic Cone Snail
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Giant Anteater
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Giant Clam
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Giant Pacific Octopus
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Giant Panda
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Giant River Otter
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Giant Squid
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Gibbon
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Gila Monster
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Giraffe
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Golden Cowrie
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Golden Eagle
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Golden Jellyfish
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Golden Lion Tamarin
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Golden Poison Dart Frog
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Gray Whale
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Great Blue Heron
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Great Egret
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Greater Flamingo
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Greater Rhea
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Great Horned Owl
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Great White Shark
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Green Anaconda
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Green Basilisk Lizard
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Green-Eyed Tree Frog
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Green Iguana
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Green Sea Turtle
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Grizzly Bear
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Groundhog
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Hammerhead Shark
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Harbor Porpoise
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Harp Seal
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Hawaiian Monk Seal
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Hawksbill Sea Turtle
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Hedgehog
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Henodus Chelyops
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Hesperornis Regalis
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Hippopotamus
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Honeybee
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Horned Toad (Short-Horned Lizard)
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Hornet
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Horse
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Howler Monkey
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Humpback Whale
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Impala
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Indian Rhinoceros
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Ivory-Billed Woodpecker
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Jackrabbit
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Jaguar
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Kemp's Ridley Sea Turtle
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Killer Whale (Orca)
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King Cobra
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King Vulture
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Kinkajou
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Koala
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Komodo Dragon
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Krill
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Ladybug
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Laughing Kookaburra
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Leafy and Weedy Sea Dragon
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Leatherback Sea Turtle
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Leopard
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Leopard Seal
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Leptoceratops Gracilis
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Lesothosaurus Diagnosticus
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Lionfish
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Little Red Flying-Fox
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Llama
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Lobster
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Locust
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Loggerhead Sea Turtle
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Lynx
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Macaw
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Madagascar Hissing Cockroach
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Mallard Duck
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Manatee
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Mandrill
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Marine Iguana
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Matschie's Tree Kangaroo
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Meerkat
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Meller's Chameleon
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Mexican Axolotl
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Mola (Sunfish)
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Mole Rat
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Monarch Butterfly
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Mongoose
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Mononykus Olecranus
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Moose
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Mosquito
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Mountain Goat
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Mountain Gorilla
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Mountain Lion
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Mouse Lemur
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Mudpuppy
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Musk-Ox
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Narwhal
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Nile Crocodile
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North American River Otter
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Northern Leopard Frog
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Nudibranch
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Nurse Shark
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Nutria
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Ocelot
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Olive Ridley Sea Turtle
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Opossum
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Orangutan
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Oriental Fire-Bellied Toad
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Osprey
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Ostrich
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Oyster
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Ozark Big-Eared Bat
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Pachycephalosaurus Wyomingensis
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Parrot
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Parrot Fish
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Peacock
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Pelican
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Peregrine Falcon
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Pileated Woodpecker
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Platecarpus
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Platypus
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Poison Dart Frog
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Polar Bear
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Porcupine
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Portuguese Man-of-War
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Prairie Dog
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Praying Mantis
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Proboscis Monkey
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Pronghorn
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Protosphyraena
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Protostega Gigas
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Przewalski's Horse
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Pufferfish
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Queen Angelfish
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Quetzal
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Raccoon
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Rainbow Trout
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Raven
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Red Crab
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Red-Eyed Tree Frog
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Red-Footed Booby
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Red Fox
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Red Kangaroo
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Red Leaf Monkey
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Red Panda
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Red-Tailed Hawk
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Red Uakari
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Rhesus Monkey
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Right Whale
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Ringed Seal
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Ring-Necked Pheasant
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Ring-Tailed Lemur
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Rockhopper Penguin
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Rocky Mountain Bighorn Sheep
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Ruby-Throated Hummingbird
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Sailfish
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Saltwater Crocodile
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Sandhill Crane
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Sand Tiger Shark
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Scarab
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Scorpion
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Sea Anemone
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Sea Cucumber
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Seahorse
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Sea Otter
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Siberian Tiger
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Sifaka
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Skunk
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Sloth Bear
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Snow Goose
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Snow Leopard
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Snowshoe Hare
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Snowy Owl
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Sockeye Salmon
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Spectacled Bear
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Sperm Whale
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Spider Monkey
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Spotted Hyena
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Spotted Salamander
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Spring Peeper
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Squirrel
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Starfish (Sea Star)
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Steller Sea Lion
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Steller's Sea Eagle
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Stick Insect
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Stingray
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Styxosaurus Snowii
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Sumatran Rhinoceros
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Sun Bear
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Tapir
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Tarantula
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Tasmanian Devil
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Thescelosaurus Neglectus
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Thick-Billed Murre
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Thomson's Gazelle
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Three-Toed Sloth
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Tiger Salamander
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Tiger Shark
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Toucan
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Triceratops Horridus
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Triggerfish
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Troodon Formosus
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Tundra Swan
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Tusotheuthis Longa
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Two-Toed Sloth
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Tylosaurus Proriger
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Tyrannosaurus Rex
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Velociraptor Mongoliensis
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Wallaby
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Wallace's Flying Frog
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Walrus
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Warthog
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Warty Newt
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Wasp
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Water Buffalo
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Web-Footed Gecko
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Weddell Seal
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Western Lowland Gorilla
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Whale Shark
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White-Eared Kob
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White Rhinoceros
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White-Tailed Deer
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Whooping Crane
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Wildebeest
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Wild Turkey
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Wolf
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Wolverine
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Wood Stork
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Xiphactinus Audax
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Zebra
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