Animal is shy, old, and extremely tame (6)
I believe the answer is:
coyote
'animal' is the definition.
(I've seen this before)
'shy old and extremely tame' is the wordplay.
'shy' becomes 'coy' (coy can mean shy or modest).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'and' is a charade indicator (letters next to each other).
'extremely' suggests removing the centre (only the extremes of the word are used).
'tame' with its centre taken out is 'te'.
'coy'+'o'+'te'='COYOTE'
'is' is the link.
(Other definitions for coyote that I've seen before include "North American animal" , "Prairie-wolf" , "predatory creature" , "Wild canine" , "Confines" .)