The most common and most likely answer to this crossword clue is the 7 letter word COYOTES
C
O
Y
O
T
E
S
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The straight part
We know that "Mammals" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mammals = coyotes.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 COYOTES mean?
COYOTES noun- Canis latrans, a species of canine native to North America.
- A smuggler of undocumented immigrants across the land border from Latin America into the United States of America.
- To prospect for gold by manually digging holes into overlying earth, as into a hillside.