Worker makes one search for it (4)
I believe the answer is:
comb
'worker' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Maybe there's a link between them I don't understand?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for comb that I've seen before include "Toothed instrument" , "Fowl's crest" , "Crest on the head of some birds" , "Implement with teeth" , "Red crest on a cock's head" .)