Animal's den (4)
I believe the answer is:
lair
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">animal's den</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for lair that I've seen before include "Home of a beast" , "Waylay" , "Home to a wild animal" , "A nautical hail" , "Rail about wild animal's home" .)