The most common and most likely answer to this crossword clue is the 6 letter word VIXENS
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result VIXENS
Buddy explains!

The straight part
We know that "Female animals" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case female animals = vixens.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does VIXENS mean?
VIXENS noun- A female fox.
- A malicious, quarrelsome or temperamental woman.
- A racy or salacious woman.
- A wife who has sex with other men with her husband's consent.