Why is a female rabbit called doe?

The term "doe" for a female rabbit comes from Old English and Middle English, where it was used to refer to any female animal.

Specifically, it derived from the Old English word "dō" which meant "female animal" and was used for various animals, including deer and sheep. Over time, it became more specifically associated with female deer and rabbits, leading to the modern usage.

So, the reason why a female rabbit is called a doe is simply because it's a historical linguistic development that reflects the use of the term for females of various species.