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

[Dann Pigdon <dannj@alphalink.com.au>]

MICHAEL HABIB writes: 

> And in fact, most mammals still go the "many small babies" route.  We have to keep in mind that cats, elephants, etc. while charismatic, do not represent the majority of mammal diversity.  The 1,000+ spp of bats (most of whom have only one or two babies at a time) bring the average litter size down a bit, but large litters of small offspring are still the rule for well over 50% of mammal species on Earth.

How many of those mammals that have lots of tiny offspring are themselves 
large? Lions are the only large mammalian predators I can think of that have 
the potential for reasonably large litters. Most others (bears, other big 
cats, humans) are lucky to have two or three offspring at a time - with 
usually one or less surviving to adulthood. 

Amongst non-predatory mammals at least, there seems to be a general trend 
for reduced numbers of offspring with increasing size. Elephants, rhinos, 
giraffes - even deer and antelope at the 'smaller' end of the 'large' mammal 
spectrum - typically have just one well-developed offspring. Of course, prey 
species have a general need to be well-developed at birth so they can run as 
soon as possible. 

All of the largest mammals alive today (including whales) tend to have just 
one offspring at a time, with long gestation periods. Although admittedly, 
bears throw a spanner in the works... 

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Dann Pigdon
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://heretichides.soffiles.com
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