[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: JFC-Bloodiest Battle ??



On Mon, Aug 25, 2008 at 11:02:26AM -0700, Erik Boehm scripsit:
> Given some sauropods rivaled whales in size, it might be worth looking
> at whales as a food source.  I know of no obligate whale scavenger... 

There are some species of hagfish that apparently have this niche, and
some other interesting but less-fishy organisms that specialize in
reducing whale bones.

I don't think this is relevant, though, because these are analogous to
foxes or beetles in a terrestrial ecosystem; they're the third or fourth
thing that has a go at a large carcass, not a primary scavenger.

The whole predator/scavenger question applied to a particular species of
dinosaur isn't really helpful, because it's a question of behaviour, and
that doesn't fossilize.  Capability might; we can tell things about how
an animal could have, and probably did, bite, but we can't tell anything
about actual behaviour. (How would you tell from the bones of a lion if
it had mostly bullied hyaenas off their kills or mostly caught its own
prey?)

So I think the more interesting question is along the lines of "how many
sauropods does it take to feed an allosaur for a year?" plus "how often
does an allosaur need to eat?"

Given the high growth rates being found by bone studies, and the
consequent high metabolisms, the "how often" number is "days, not
weeks"; given the relatively small number of sauropods (the number might
be less than 1! 30 ton Apatosaur versus 1 ton Allosaur; the Allosaur
isn't going to eat ten times its body weight in a year, and there has to
be at least that much food on an Apatosaur), and a certain expectation
for rapid consumption/rotting on the part of a carcass, the only
possible answer (if the Allosaur is mostly eating sauropods), is that it
was eating small bits of lots of sauropods, which in turn implies either
pack hunting if eating adults (it's kinda like foxes preying on red deer
or elk) or preying on juveniles that it could hope to capture
individually.  It doesn't imply scavenging because the maximum time
between feedings is low, and the expected natural mortality rate
wouldn't be even; even if there's enough death from other causes in the
sauropod population, it would not happen evenly; it'd be concentrated in
times of environmental stress.

Also, turn this around; sauropods laid large clutches and appear to have
had no parental care.  *Something* is eating the young.

-- Graydon