Eagles, among the world's most iconic birds, are largely found in Eurasia and Africa. Only a few species live in the Americas, including the uncommon black and chestnut eagle, with fewer than 250 adults alive in the wild.
El Rincon stream frogs live on a solitary plateau in Argentinian Patagonia, at the southernmost point of South America. These frogs survive the harsh winter by living in mild thermal streams.
The northern river terrapin (Batagur baska) is one of the world's most endangered freshwater turtles. Their numbers once spanned the mangrove swamps, rivers, and estuaries of West Bengal and Odisha in India, but have since fallen due to overfishing, sand mining, and pollution.
Many indigenous species live on small islands. Dinagat Island, in the south of the Philippines, is home to two exceptionally unusual animals: the Dinagat moonrat and the Dinagat hairy-tailed rat.
Hirola, the world's most endangered antelope, is found in small numbers in the wild. Since the 1970s, when an estimated 14,000 antelope roamed the grasslands of Kenya and Somalia, multiple tragedies have reduced their numbers to only 600.
The critically endangered Albany adder, a dwarf adder species, lives in South Africa. This snake is one of the rarest in the world, with only 17 recorded records.
Despite extensive efforts to locate other populations, Roach's mouse-tailed dormouse is only known to live in south-western Bulgaria. It is one of Europe's least-known and most rare rodents.
Bawean warty pigs, situated on the Indonesian island of Bawean, may only number a few hundred. They are closely related to the Javan warty pig, although they are a separate species that diverged approximately 160,000 years ago.
Golden langurs, one of the world's 25 most endangered primates, have seen their numbers plummet by up to 60% in Bhutan. The only other known population is in Assam, northern India.
The critically endangered Siamese crocodile originally roamed much of mainland Southeast Asia. It is currently extinct in 99% of its original habitat, and the wild population of mature Siamese crocodiles is expected to be under 250.