The most common and most likely answer to this crossword clue is the 4 letter word ZOIC
Z
O
I
C
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The straight part
We know that "about animals" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case about animals = zoic.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 ZOIC mean?
ZOIC adjective- Showing traces of life; containing organic remains.
- Having the form of an animal; animal-like, zoomorphic.