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ARE OSTRICHES REALLY BLIND AT NIGHT?



    John Bois commented, "On the other hand, ostriches are easily driven off
nests by even smaller-than-lions blackbacked jackals..."

    Of course, ostriches may seem to be 'driven off' their nests by jackals,
but what ostrich could literally 'kick ass' on jackals just sitting on the
nest?  Could they be just getting off their nests in order to 'kick ass' if
necessary?  That said, I doubt the typical ostrich would be a wanton killer
and go around kicking jackals to death just because they wander into nesting
territory. That could ultimately make an unwholesome stink in which to
brood, and other attendant problems.

    As a side thought: Couldn't jackals be helpful to ostriches by scaring
off some other potential egg predators?

    John further said, "--this is done at night when jackals can see and O's
[sic] can't."

    Of course jackals can probably see considerably better at night than can
ostriches, but to say ostriches can't see at night seems incredible.  Why
else those pupils that can open so wide?  Even if an ostrich has been
sleeping and the eyelids have been closed, since pupils tend to be dilated
behind closed eyelids at night, immediately upon awakening, the ostrich
should see reasonably well, I suspect.  Fact is, I don't know of any bird
that cannot see at night.

    It would probably not be unreasonable to expect the same capability of
mesozoic dinosaurs, large or small.

    One might see 'ostrich night blindness' in a filmed production, but keep
in mind that if a movie camera operator shines bright light at a sleeping
ostrich and it awakens and stares into the bright light source, it may
quickly become temporarily blind to the ambient relative darkness in other
directions by pupil contraction, but that is not a normal situation.

    Ray Stanford

"You know my method.  It is founded upon the observance of trifles." --
Sherlock Holmes in The Boscombe Valley Mystery

----- Original Message -----
From: "John Bois" <jbois@umd5.umd.edu>
To: <Tthecoolguy@aol.com>
Cc: <dinosaur@usc.edu>
Sent: Wednesday, March 13, 2002 3:54 PM
Subject: Re: (Now cats vs. "raptors")




On Wed, 13 Mar 2002 Tthecoolguy@aol.com wrote:

> Ostriches are known for their very hard kicks, and have been known (or so
> I've read) to break a lions jaw with one and another incident involving an
> ostrich ripping a lion's guts open with it's relatively blunt toe claws.
I
> can't prove these as I forgot where I even read them.  But if  the
ostriches
> had toe claws......


On the other hand, ostriches are easily driven off nests by even
smaller-than-lions blackbacked jackals--this is done at night when jackals
can see and O's can't.  Also, ostriches are known to avoid treed areas it
is thought because they provide stalking cover for lions.  Lion predation
on ostriches is very rare.