Out of curiosity, I checked Reverso.com (in context) to find that out of the first 200 or so entries of "chatte", only about 11% refer to an actual "cat" and 1% are terms of endearment. The remaining 88% were used in a vulgar context. There were ZERO occurrences of "female cat". Duolingo believes it is important that you know the difference between "un chat" and "une chatte", and I agree. It should be noted that the term "female cat" is not used by English-speaking persons in this context.