Ai is also a kind of sloth, of the genus Bradypus. Ais are differentiated by their having three toes from sloths of the genus Choloepus, who have two. Other differences include number of vertebra (three toed sloths have nine, two toed ones six or seven) and tails (ais have them).
Three toed sloths are called "ai" (pronounced "eye") because it is similar to the sound the sloth makes.
There are at least three species of three toed sloths, all located in Central and South America.
Ai is a useful scrabble word.