Catalogued on the IUCN Red List of Threatened Species as "critically endangered", this unusual looking creature is now known to occur in just three separate populations on Indonesia's tiny Rote Island. Named for its neck, which can grow to lengths of between seven and nine inches, the species commands high prices in the commercial pet trade.

Native to South America, these carnivorous bottom-feeders hang out in the shallows of streams and swamps, where their camouflage gives them the edge over unsuspecting prey. Given its poor eyesight, it relies on other sensory aids, such as nerves near its mouths, to snag small fish and invertebrates. They don't move about much, but poke their long snouts out of the water in order to breathe.

It is from these beautiful ocean-dwellers that tortoiseshell derives its name, and as a result of the coveted material's decorative popularity the species has suffered a decline of more than 80 percent in the past century. Although international trade of hawksbill shells is now illegal, it continues on the black market. They are listed as critically endangered.

Alternatively named the forest softshell turtle, this long-necked animal is found in the fast-flowing streams and quiet muddy backwaters of several Southeast Asian countries. Their shells might be soft, but their jaws are powerful enough to crunch the snails and molluscs that are their prefered food. They use their snout for breathing.

This creature might be wearing a cute smile, but looks can be deceptive. Native to countries across sub-Saharan Africa, these omnivorous turtles will eat whatever they can get their little claws into. They have been observed picking parasites from the bodies of rhinos and warthogs and working in groups to catch and drown birds such as doves.

At home in the lakes and rivers of the southeastern US, these prehistoric-looking creatures can theoretically live for 100 years. They are currently listed by the IUCN as "vulnerable" due to habitat disruption and capture for meat. They feed by luring prey into their open jaws with a worm-like appendage on their tongues. The strategy clearly works, as males can easily weigh 68 kilos (150 pounds).

But that's nothing compared to the leatherback, which can reach lengths of two meters (6.5 ft) and weights of 900 kilos. The world's largest turtles, which as their name suggests, have a leathery rather than a hard shell, are capable of migrating as far as 16,000 kilometers annually. They are listed as "vulnerable" by the IUCN.

Deriving their name from the little snout they use to like a snorkel to breathe, and to forage for food, the pig-nosed turtle is found in freshwater rivers, lagoons and streams in the Northern Territory of Australia and on New Guinea. Exploitation for meat and eggs, habitat loss and the exotic pet trade have contributed to this unique creature's "vulnerable" status on the Red List.