Belonging to the subfamily in which Takin and Ibexes belong to, the Balearic Island Cave Goat is a strange species that once lived on the Spanish islands of Majorca and Minorca. They had eyes that were front facing unlike most herbivorous mammals, which gave them stereoscopic vision. Their lower incisors had a perennial growth pattern, like rodents, too.

Small, they stood at only 50 centimetres (19 inches) at shoulder and weighed only around 50 to 70 kilograms (110 to 154 pounds). They grew at a rate similar to crocodiles, intermittently halting growth altogether, lending some to believe that their metabolisms adapted to ambient temperature and food availability. This would make them more like a “cold-blooded” reptile than a mammal.

The reason for it’s extinction is still up for debate. The leading causes are climate change and the introduction of humans to the islands. The first human colonization of the islands was not before 3000 BC. The Balearic Island Cave Goat remains that have been found appear to show some attempts at domestication. But their long maturity rate, reaching full growth at 12 years of age, did not make them suitable to the demands of farming.

This failure of domestication, along with introduced species such as dogs, sheep, pigs, and cows, likely led to the rapid extinction of this unique creature.

Extinction Date: About 5,000 years ago