Andrew Vik
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Dear Nora and Paulino:

I guess this is one of those "which came first, the Chicken or the Egg" type
discussions.
The best answers still amount to educated speculation. Most predators will resort to
scavenging in the right situation, and some seem to prefer it (opportunistic
scavengers). The number of animal species that eat only carrion (true scavengers) is
quite small when compared with the part time scavengers. Here are some examples of
full time scavengers which originated from predatory ancestors. The Vultures and
Condors (Aves, Cathartidae) are specialized raptors. The Slime Hags (Agnatha,
Myxinoidea) are jaw less fishes that consume a carcass from the inside out. I can
think of no examples of predators that evolved from full time scavengers. That is one
of the reasons why some paleontologists theorize that the highly specialized
Tyrannosaurus (its forelimbs were quite useless) was a carrion fancier.

True, our  human chauvinism is what makes us take more interest in predators than the
more highly specialized scavengers and parasites. We are predators ourselves. But even
humans will resort to scavenging and even cannibalism in hard times.

I'll now try to bring this thread back in line with our subject, Malacology.
Does anyone know of any molluscs that are full time scavengers?

Yours, Andrew

NORA BRYAN wrote:

> We were discussing this issue again last night and were thinking about the raging
> T-Rex controversy - was T-Rex a predator or a scavenger?  We'll never know for
> sure, but some people go to great lengths to 'prove' that they were predators -
> i.e. they are more noble creatures being predators, and have better box-office
> billing.  Jurassic Park would not have been so thrilling for audiences if T-Rex
> was poking through garbage dumps for tasty morsels!
> I think most so-called predators and scavengers are opportunistic feeders anyway -
> meat is meat, although some animals like most cats disdain old meat.
> In George Schaller's famous book about lions, he showed that different prides have
> different habits but that many lion prides got a good portion of their meat by
> driving hyenas off their kills.  This shocks some people because after all lions
> are noble animals and hyenas are scavengers - right???
>
> Kay Lavalier wrote:
>
> > Andrew Vik
> > [log in to unmask]
> >
> > Dear Nora:
> >
> > I agree with you 100%. Scavengers do a very important job on this planet. They
> > just aren't as exciting as predators are. But we must realize, most scavengers
> > have evolved from predators, not the other way around. I do not believe in
> > de-evolution, the idea that life forms can regress to a more primitive state.
> > Therefore, scavengers could be thought of as an improved predators.
> >
> > Yours, Andrew
> >
> > NORA BRYAN wrote:
> >
> > > Andrew
> > > Interesting choice of phrase -  "defaming".  It's odd how we tend to think
> > > of scavengers as somehow less worthy of our admiration.  I guess it's a
> > > natural reaction (maybe we picture ourselves eating roadkill and get a
> > > little grossed out at the idea!).   Of course we know logically that
> > > scavengers are an extremely important part of the natural cycle.  Sometimes
> > > when I see a dead animal I feel sad, but then I feel better when I see the
> > > various birds and animals making use of the carcass to feed themselves and
> > > their young.  Death feeds life.
> > >
> > > Nora
> > > Calgary, Alberta
> > > CANADA
> > >