The most common and most likely answer to this crossword clue is the 4 letter word BOAR
I've seen this crossword clue in The Guardian
B
O
A
R
More clues leading to the result BOAR
- Nothing in watering hole for pig
- Acorn eater rather a dull chap, I hear
- Nothing in pub for a snuffling customer?
- Male Director leaving the rest of the Directors?
- Brief supporter of games above and other game
- Steal up around a wild beast
- Black blade gets beast
- Swine in pub, drinking nothing
- Animal runs after snake
- Hog finds love in watering hole
Buddy explains!

The straight part
We know that "Animal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case animal = boar.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 BOAR mean?
BOAR noun- A wild boar (Sus scrofa), the wild ancestor of the domesticated pig.
- A male pig.
- A male boar (sense 1).
- A male bear.
- A male guinea pig.