Re: Crocs and the K-T

["Adam Britton" <abritton@wmi.com.au>]

From: <KELL00BELL@aol.com>
Sent: Friday, July 20, 2001 3:11 PM


> But how could Stomatosuchus kill dinosaurs with the small
> teeth of its upper jaw, and its weakly constructed, toothless lower jaw?

I thought Stomatosuchus was completely toothless? Last I read, which was
admittedly a couple of years ago, it was suggested that this animal may have
filter-fed - a rather bizarre, but curious idea. Has new evidence come to
light recently? The first and I thought only existing fossil was destroyed
back in WW2.


> Perhaps it bolted down baby titanosaurs whole.  No crocodile, no matter
how
> well-armed, could overcome massive adult titanosaurs, but there were many
> small ones after the nesting season.  The African climate was no less
> sweltering then, and titanosaurs, like modern mammals, frequently drank or
> immersed in water to cool off.  Stomatosuchus had many opportunities to
> select victims of small size.  In America, Deinosuchus evolved the means
to
> kill ornithiscians, which were small enough to be beatable, even when
adult.

There's a misconception that big crocodilians eat nothing but large prey.
The principal diet of all crocodilians is small vertebrates and
invertebrates, all of which were abundant during that period. Even 17 foot
saltwater crocodiles today have very limited access to large mammals through
much of their range, and feed primarily on fish, crustaceans and small
mammals, yet attain large sizes in a decade or two.


>     Crocodilian survival should, however, limit the factors responsible
for
> the K-T, specifically ruling out an impact winter.  No crocodilian was
likely
> to have survived the severe plunge in temperatures resulting from the
> hypothesized loss of sunlight for months or years.  Even alligators, which
> hibernate, are confined to mild, southerly areas.

That depends upon the severity and duration of the unfavourable conditions,
and the degree to which crocodilians could have buffered themselves against
it. Both _Alligator_ species can survive freezing conditions for weeks or
months, but did these conditions really last for years around the entire
globe?


> but crocodilians had an advantage, the
> ability to bask.  That would explain their survival, provided there was no
> interruption of sunlight.

Crocodilians don't necessarily need sunlight to warm their bodies - warm
ambient temperatures, whether in the water or on land, do just as well.

Adam