Critically Endangered (CR)
The IUCN Red List category immediately before extinction in the wild. Populations are small enough that individual animals matter to the total.
Amur Leopard
The rarest big cat in the world, with fur up to three inches long in winter, living alone in the forests of the Russian Far East and northeast China.
Axolotl
The smiling cyber-amphibian that keeps its larval gills as an adult and can regrow whole legs and parts of its own brain and heart.
Beluga Sturgeon
A giant sturgeon that mostly hunts open-water fish and now survives largely through hatcheries.
Black Rhinoceros
A hooked, prehensile lip, a recorded top speed of about 34 miles per hour, and two horns that grow from the skin all its life.
Bornean Orangutan
Borneo's biggest mammal in the trees: long arms for the canopy, hands and feet that both grip, and a long call that can be heard a kilometer or more away.
Coelacanth
Thought to have gone extinct over 65 million years ago, then found alive in 1938, with fleshy fins that move like a four-legged animal's legs and a pregnancy of around five years, possibly the longest of any vertebrate.
Cuban Crocodile
One of the most threatened crocodilians in the Americas, able to leap from the water for prey on overhanging branches, with teeth adapted for crushing turtle shells.
European Eel
A river fish thought to spawn only in the Sargasso Sea, after a 5,000 to 10,000 km migration, though its spawning has never been observed.
Gharial
The narrow-snouted river crocodilian with up to 110 razor-sharp teeth, whose males grow a bulbous nasal resonator that buzzes as they exhale.
Giant Clam
The largest living bivalve gets most of its nutrients from algae living in its flesh.
Great Hammerhead Shark
A hammer-shaped head wired with electric sensors, used to pin stingrays to the seafloor.
Harlequin Poison Frog
A rainforest frog just 2.5 to 3.8 centimetres long, painted like a warning label, its skin toxins collected straight from the ants, termites and beetles it eats.
Kakapo (Owl Parrot)
The heaviest parrot in the world, camouflaged in moss-green feathers, betrayed by its own strong scent, and courting with a boom heard up to five kilometres away in ideal conditions.
Red Abalone
A one-shell snail relative that clamps onto rock with a muscular foot and builds mother-of-pearl 3000-fold tougher than the mineral it is mostly made of.
Scalloped Hammerhead
A wide head that seems to sense prey no better than a sandbar shark's, but searches a wider area and can pivot into sharp turns at high speed.
Staghorn Coral
An antler-shaped coral that can grow up to 8 inches of branch a year, yet lost 97 percent of its numbers to one disease.
Sunda Pangolin
A scale-armored mammal that swishes its tail with its scales erect, then curls into a near-impregnable ball when threatened.
Vaquita
A shy porpoise with the smallest range of any whale, dolphin or porpoise
Conservation categories are from the IUCN Red List of Threatened Species. AnimalTracks is independent of IUCN.