Re: Regarding Spinosaurus

["Michael Hanson" <mhanson54@attbi.com>]

Tim Williams wrote:

> >In response to HP Williams' idea that the best way to test this
> >hypothesis is to find a "naked" spinosaurid snout: first of all, as he
> >alluded, finding this type of integument will likely be very difficult
>
> Ubetcha.
>
> (And the entire head would be naked, not just the snout.  Strictly
speaking,
> all birds have "naked" snouts, since their not covered with feathers.)
>
> >However, even if it were to be found, a naked spinosaurid is not a
> >foolproof way to "prove" Graydon's hypothesis.
>
> A naked-headed spinosaur would "corroborate" (the word I used) the idea of
a
> mode of life that involved scavenging and/or sticking your head inside the
> rib cage of a carcass.  Yucky business, and it's good not to foul any more
> feathers than are necessary.  (The naked heads and legs of certain
vultures
> do serve an additional purpose in thermoregulation; the legs are often
> whitewashed with urea for evaporative cooling.)

With a large sail most likely used for thermoregulation, spinosaurs probably
did not have this habit.(not to say I don't like the idea of  a naked head)

> >Of course, there are many other imaginable
> >scenarios that may explain why the snout would be naked (even a
> >fish-catching adaptation, such as the use of a naked snout for better
> >aerodynamic properties in water, may be feasible).

A naked snout would have many advantages in the water as well as on land
(for a scavenger).

> I suppose this would be "hydrodynamic".  ;-)
>
> >I still think that
> >the best method by which to test this is to compare the spinosaurid
> >skulls and dentition to modern forms that perform similar methods of
> >feeding.
>
> Then we come back to crocs and piscivory.

But crocodilians can also scavange. The problem is that no hunters are
strictly hunters and no scavangers strictly scavange. Modern hunters such as
crocodiles will occaisonly scavange depending on the conditions. Scavangers
like vultures will (very, very rarely) hunt for food if there isn't anything
already dead to eat. I think that it is safest to say that spinosaurs were
part scavangers and part piscivores, spinosaurs may have occaisonally hunted
as well.