The riverine rabbit is among the rarest rabbit species in the world. Considered 'critically endangered', only around 250 individuals survive in a few areas of the Karoo Desert in South Africa — where they typically live along seasonal rivers.

The Titicaca water frog lives solely in the depths of Lake Titicaca in the Andes mountains at elevations of 3,810 metres (12,500 feet). Its copious skin folds allow it to breathe — through cutaneous respiration (skin breathing) — at such high altitudes, its lungs are only 1/3 the size they should be.

The pancake tortoise's shell is uniquely flat and flexible. While this lightweight armouring doesn't offer much defence, it does make it the fastest of all tortoise species. When in danger, it will swiftly wedge itself in between rocks.

The Devils Hole pupfish is perhaps the rarest fish in the world. It lives in the desert; its entire population is found in one 33.8°C (93°F) pool — mostly on a 3.5 by 5 m (11 by 16 ft) rock shelf — inside a cave in Death Valley, Nevada.

The jaws of a Tasmanian devil can open to an 80-degree angle, able to deliver the strongest bite of any carnivorous mammal relative to body size. Nicknamed the "Australian hyena", the devil is a bone-crunching scavenger, gorging on dead bodies before they can fester and spread disease.