Re: Naked heads (was Velociraptor Animation)

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Williams, Tim" <TiJaWi@agron.iastate.edu>
Sent: Thursday, April 11, 2002 12:44 AM


> David Marjanovic wrote:
>
> > While many vultures (not all, *Gypaetus barbatus* is a notable
> > exception) do have naked heads and necks like this, hyenas don't. So
> > this is equivocal.
>
> _Gypaetus barbatus_ (the lammergeier) specializes in eating the marrow of
> large bones - which they smash into manageable pieces by dropping onto
rocks
> >from a great height.  They are also reported to do this for tortoises, to
> get to the good stuff inside.  Yum yum.  In any case, lammergeiers don't
> typically go diving headfirst into the torsoes of carcasses.

My big book on recent vertebrates (a translation of an English original, but
I can't find the original title) says it "eats all kinds of carrion,
including human one, but frequently has to let bigger vulture species in
first. Because it gets its turn as one of the last ones, often only the
bones remain for it. Therefore it has developped the behaviour of dropping
them from great heights onto rocks". BTW, Lämmergeier, because it often
tries to eat dead lambs [1 Lamm, 2 Lämmer] when the mother is still there
and defends it, though more normal in German is Bartgeier.

> The correlation for scavenging birds having naked heads and necks is
pretty
> good: vultures from the Old World (Accipitridae) and New World (Vulturidae
/
> Cathartidae) show this feature, as does the carrion-eating marabou stork
> (Ciconiidae).  Thus, bare heads evolved at least twice in the Aves (three
> times if it evolved independently in the marabou and its kissing cousins,
> the vulturids.)

It is pretty good but not perfect...
Anyway, vultures hardly have a possibility to clean feathers on their necks;
*Velociraptor* would reach there with its finger claws. Might make a
difference.