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From: andrewt@cs.su.oz (Andrew Taylor)
Newsgroups: sci.bio
Subject: Re: Killing for fun (hunting skills)
Message-ID: <2145@cluster.cs.su.oz.au>
Date: 1 Mar 91 01:24:49 GMT
References: <1991Feb26.202248.26171@odin.corp.sgi.com> <2132@cluster.cs.su.oz.au> <28836.27cc6593@kuhub.cc.ukans.edu>
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Reply-To: andrewt@cluster.cs.su.oz (Andrew Taylor)
Organization: Basser Dept of Computer Science, University of Sydney, Australia
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In article <28836.27cc6593@kuhub.cc.ukans.edu> kuento@kuhub.cc.ukans.edu writes:
>> Californian Sea Lions will occasionally kill Marine Iguanas during play.
>> South American Sea Lions will kill Magellenic Penguins, 
>
> Yes, there are, and they all have one thing in common which suggests
> it is NOT purely for fun - the animals that are killed are either
> normal prey items, or have characteristics similar to normal prey. The
> answer is simple - the animal is *practicing* its hunting technique,

I disgree. Neither of the examples have similar characteristics to the normal
prey. Marine Iguana are slow surface-swimming targets which try to escape to
shallow water. Magellenic Penguins main evasive manoeuvres involve porpoising.
I can see no advantage for the Sea Lions learning to cope with these tactics.
Their prey does not do these things.  At least in the second case the
individual had been an adult for at least several years and hence presumably 
its hunting skill were well developed.

Other play by Sea Lions is does not develop hunting skills (e.g swimming
inverted below you while blowing bubbles at you).

Andrew Taylor