Another word with evolutionary significance.
A chevrotain is also known as a mouse deer (which can be somewhat deceptive). The name comes from French, and roughly translates as 'little goat'.
They're actually a group of species (called a 'family' in the old, Linnean classification) found in Africa and Southeast Asia - with some variation in appearance between species. This grouping includes the smallest ungulates in the world.
The rodent features are misleading, and would be an example of convergent evolution - that is, unrelated animals that evolves similar features for similar environmental niches.
Where did I encounter this word? This is what makes this species significant: recently there was a Wikipedia feature article on giraffes. They're (even-toed) ungulates - which evolved from creatures that looked rather like this 54 million years ago.