The most common and most likely answer to this crossword clue is the 5 letter word ZEBUS
Z
E
B
U
S
More clues leading to the result ZEBUS
Buddy explains!

The straight part
We know that "beasts" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case beasts = zebus.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 ZEBUS mean?
ZEBUS noun- A domesticated ox native to Asia and Africa, having a large fleshy hump on its back and a dewlap (Bos primigenius indicus).