Animals an older boy bores (9)

I believe the answer is:

mandrills

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'animals' is the definition.
(I've seen this before)

'an older boy bores' is the wordplay.
'an older boy' becomes 'man' (I am not sure about the 'older' bit.).
'bores' becomes 'drills' (I've seen this before).
'man'+'drills'='MANDRILLS'

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(Other definitions for mandrills that I've seen before include "Animals" , "Monkeys" , "primates" .)

I've seen this clue in The Daily Express.

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