The most common and most likely answer to this crossword clue is the 4 letter word STAG
I've seen this crossword clue in The Daily Telegraph
S
T
A
G
More clues leading to the result STAG
- Short period without a female companion
- Cut theatre for men only
- Singular epithet for men
- Lass finally catching game, unaccompanied male
- Mount tailless deer
- Singular label for men only
- Noble animal guns knocked over
- This is mostly put on for men
- Speculator initially selling tin and gold
- Man in cave is smart, not revealing name
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 = stag.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 STAG mean?
STAG noun- An adult male deer.
- A colt, or filly.
- (by extension) A romping girl; a tomboy.
- An improperly or late castrated bull or ram – also called a bull seg (see note under ox).
- An outside irregular dealer in stocks, who is not a member of the exchange.
- One who applies for the allotment of shares in new projects, with a view to sell immediately at a premium, and not to hold the stock.
- The Eurasian wren, Troglodytes troglodytes.
- (usually attributive) An unmarried male, a bachelor; a male not accompanying a female at a social event.
- A social event for males held in honor of a groom on the eve of his wedding, attended by male friends of the groom, sometimes a fund-raiser.
- A stag beetle (family Lucanidae).
- Guard duty.
- To act as a "stag", an irregular dealer in stocks.
- To watch; to dog, or keep track of.
- Of a man, attending a formal social function without a date.