Stories about water mammals in chancy endeavours (9)

I believe the answer is:

lotteries

'chancy endeavours' is the definition.

'stories about water mammals' is the wordplay.
'stories' becomes 'lies' (I've seen this before).
'about' is an insertion indicator.
'water mammals' becomes 'otter' (I can't explain this - if you can you should believe this answer much more).
'lies' enclosing 'otter' is 'LOTTERIES'.

'in' acts as a link.

I've seen this clue in The Times.

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