The most common and most likely answer to this crossword clue is the 5 letter word WHALE
I've seen this crossword clue in The Sunday Telegraph
W
H
A
L
E
More clues leading to the result WHALE
- Thrash for one with large appetite
- Cry out loud for marine animal
- Sea creature in western sound
- Sea creature’s plaintive cry you can hear
- Swimmer’s fit after first of workouts
- Wife has fit, seeing one in the water?
- This might describe a good time for one in school
- Owner of 9 with empty drink
- Wide, blooming large creature
- Giant scream heard?
Buddy explains!
The straight part
We know that "Large mammal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case large mammal = whale.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 WHALE mean?
WHALE noun- Any of several species of large sea mammals of the infraorder Cetacea.
- Something, or someone, that is very large.
- Something, or someone, that is excellent.
- In a casino, a person who routinely bets at the maximum limit allowable.
- An investor who deals with very large amounts of money.
- (by extension) A video game player who spends large amounts of money on premium content.
- To hunt for whales.
- To thrash, to flog, to beat vigorously or soundly.