Slow-moving mice may get snapped up by them (4)
I believe the answer is:
owls
'mice may get snapped up by them' is the definition.
I can't judge whether this definition defines the answer.
'slow-moving' is the wordplay.
'moving' indicates an anagram.
'slow' with letters rearranged gives 'OWLS'.
Can you help me to learn more?
(Other definitions for owls that I've seen before include "Slow (anag) -- birds of prey" , "Types incredibly wise" , "Strigiform creatures" , "Nocturnal bird" , "Slow sort of birds" .)