Fw: Carnivore Energetics: Why Are Lions Not As Big As Elephants?

[john bois <jbois@verizon.net>]

----- Original Message ----- 
From: "john bois" <jbois@verizon.net>
To: <martin.baeker@tu-bs.de>
Cc: "Dann Pigdon" <dannj@alphalink.com.au>; "DML" <dinosaur@usc.edu>
Sent: Saturday, January 20, 2007 10:00 AM
Subject: Re: Carnivore Energetics: Why Are Lions Not As Big As Elephants?


> Yes...your argument makes good sense!  But still I would see the tooth
> arrangement as the _result_ of a successful parental investment strategy
> rather than an eternal mammalian prohibition against multiple offspring.
> Not much evidence to support that statement, I know...but toothless whales
> still "opt" for single babies.  Elephant-sized animals could have more
than
> one baby regadless of teeth (right?)...but seem to "choose" not to.
>
> Also, regarding K and r strategies: they are rule-of-thumb concepts at
best;
> maybe relevant for within clade discussions, but not so much across
clades.
> For example, given the very different reproductive modes of the respective
> animals, in identical Serengeti conditions it might still be better for an
> elephant to have one baby and a sauropod to have many!
> ----- Original Message ----- 
> From: "Martin Baeker" <martin.baeker@tu-bs.de>
> To: <jbois@verizon.net>
> Cc: "Dann Pigdon" <dannj@alphalink.com.au>; "DML" <dinosaur@usc.edu>
> Sent: Thursday, January 18, 2007 3:31 AM
> Subject: Re: Carnivore Energetics: Why Are Lions Not As Big As Elephants?
>
>
> > > Further,
> > > I don't believe there is any physiological constraint on a large
> > > mammal having many small babies rather than one large one.
> >
> > I think there is.
> >
> > Mammals have two sets of teeth at most. If the offspring is several
> > orders of magnitude smaller than the mother, they would have to be
> > suckled for a *long* time. Otherwise, they would need a first set of
> > teeth when they are very small, they need an approximately adult-sized
> > set for later, and in between their teeth would show very large
> > gaps. The alternative were for the mother to suckle them for a long
> > time (marsupial strategy) until they are large enough that the first
> > set of teeth will get them over to the size where the second set can
> > come in. This, however, becomes equivalent to the other strategy.
> >
> > Please also note in this discussion that the two strategies (r and k)
> > are usually interpreted as answers to different conditions: the
> > child-care strategy is good if you are living on a rather constant
> > food source, the mass-offspring strategy is better if food source
> > availability may vary strongly, so you can get a lot of offspring
> > quickly when a sudden plentiness of food is available.
> >
> > Martin.
> >
> >                    Priv.-Doz. Dr. Martin BÃker
> >                    Institut fÃr Werkstoffe
> >                    Langer Kamp 8
> >                    38106 Braunschweig
> >                    Germany
> >                    Tel.: 00-49-531-391-3073
> >                    Fax   00-49-531-391-3058
> >                    e-mail <martin.baeker@tu-bs.de>
> >
>