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Re: dino-lice



Hey Jason! Yeah, I guess that's my point. What evidence would you need
to prove an animal is primarily a scavenger, beyond the scavenging
that just goes with being a predator? I guess it depends on corpse
occurence, distribution and size. If big things are dying everywhere
all the time, anything can live entirely from scavenging. If small
things are dying far apart at long intervals, you either need to be
lucky enough to be in the vicinity (and you can't specialise in being
lucky) or be able to sense the corpse and travel to it faster than
everything else, or at least fast enough to get there before the
things stripped.

If it's something in the middle (which seems the most plausible), I
guess everything scavenges when it can and predates the rest of the
time, but to get most of their calories from scavenging, an animal
would still need to be better at finding corpses and getting to them
than other animals.

So what: To say something was a specialised scavenger, you'd need to
know something about corpse density and distribution, corpse calories,
density, distribution and calorific intake of other meat eaters,
relative sensual acuity (for a terrestrial animal I would bet this has
got to be smell, I can't see how vision would work over long enough
distances) and secondarily to that relative locomotion speed and
economy of other meat eaters.The ability to eat the corpse when you
get to it seems to be pretty trivial. What do you guys think?

On 19 April 2011 02:43, Jason Brougham <jaseb@amnh.org> wrote:
> Hi Vivian,
>
> If it is relevant to your discussion I remembered that teeth from the
> dromaeosaurid Saurornitholestes were found imbedded in the the tibia of a
> huge pterosaur in Dinosaur Provincial Park. The pterosaur was so large
> that the authors assumed it had been scavenged after death.  There are
> also the marks that suggest that Deinonychus scavenged large Tenontosaurs
> that had become mired or died in the Antlers Formation.
>
> I think what we need is a good understanding of scavenging ecology. My
> understanding from studies in the Serengeti is that every predator kills
> and every predator scavenges, and carcass stealing is ubiquitous.
>
> -Jason
>
>> Apologies - plaintext below (new to the whole DLM shebang)
>>
>> I mean, opportunistic scavenging is a basic feature of carnivory -
>> saying something scavenged carcasses is in general tantamout to just
>> saying it ate meat. To be a convincing dedicated scavenger you either
>> need a way of both finding and getting to corpses (which are probably
>> a pretty thinly-spread resource) before every other meat-eater that
>> happened to be near it gets involved. So you need to cover a wide area
>> with a fast-acting sense, and be able to travel large distances
>> quickly. birds seem the only convincing terestrial example at the
>> moment. Or you eat the stuff no-one else is going to or is able to
>> (bones, waxy residues etc), or you exist in such huge numbers that
>> you're basically everywhere anyway (flies, ants etc). Does that sound
>> about right? Being able to process a large corpse doesn't really make
>> you anything more than a carnivore, as far as I can see - it's the
>> ability to sense and travel over long distances quickly (relative to
>> competitors). Might be wrong.
>>
>> On 18 April 2011 23:37, Vivian Allen <mrvivianallen@googlemail.com> wrote:
>>>
>>> Sorry to trot out the obvious argument, but how would a non-flying
>>> obligate scavenger find meals quickly enough to compete with
>>> opportunistic scavengers? (i.e. every carniverous species withing
>>> detection range of a carcass). Anyways, my vote would also be for
>>> atrophied, unless there is compelling evidence otherwise.
>>>
>>> On 18 April 2011 23:23, Dann Pigdon <dannj@alphalink.com.au> wrote:
>>>>
>>>> On Tue, Apr 19th, 2011 at 4:01 AM, Augusto Haro <augustoharo@gmail.com>
>>>> wrote:
>>>>
>>>> > It may be, although I suspect that dinosaurs with great olfactory
>>>> > acuity as tyrannosaurids and dromaeosaurids may reach it before and
>>>> > open the carcasses then. I would also expect more laterally
>>>> compressed
>>>> > unguals, dromaeosaur-style, if expecting carcass hide-cutting.
>>>> > Besides, I do not see in the shout of alvarezsaurs much indication of
>>>> > carrion-eating, such as recurved beak or teeth...
>>>>
>>>> Who needs to pierce hide when you've got a narrow head and long neck,
>>>> and nature has provided
>>>> a ready-made access chute for reaching the intestines? Some of the
>>>> smaller vulture species that
>>>> lack the strength to pierce hide opt for the sphincter option.
>>>>
>>>> I've always wondered whether alvarezsaur forelimbs were attrophied from
>>>> general lack of utility
>>>> (as in Carnotaurus), with the only function left being that of
>>>> intraspecific kangaroo-style wrestling
>>>> matches.
>>>>
>>>> --
>>>> _____________________________________________________________
>>>>
>>>> Dann Pigdon
>>>> Spatial Data Analyst               Australian Dinosaurs
>>>> Melbourne, Australia               http://home.alphalink.com.au/~dannj
>>>> _____________________________________________________________
>>>>
>>>
>>
>
>
> Jason Brougham
> Senior Principal Preparator
> Department of Exhibition
> American Museum of Natural History
> 81st Street at Central Park West
> 212 496 3544
> jaseb@amnh.org
>
>