body size of animals

The size of the largest animal in a land area is related to the size of the land area

A group of researchers who studied the largest animals over the past 65,000 years concluded that "maximum body size is determined by the number of home ranges that can fit into a land area," that is, for example, the biggest animal in Eurasia will be bigger than the biggest animal in Australia. They also found that within any given land area, the biggest warm-blooded (endothermic) herbivore tended to be roughly 14 times more massive than the biggest warm-blooded carnivore; for cold-blooded (ectothermic) animals, the ratio was about 33. Within a land area, the biggest ectothermic herbivore was bigger than the biggest endothermic herbivore, and both were bigger than the biggest ecothermic carnivore, which was bigger than the biggest endothermic carnivore.

Gary P. Burness, Jared Diamond and Timothy Flannery.
Dinosaurs, dragons, and dwarfs: The evolution of maximal body size.
Proceedings of the National Academy of Sciences, vol. 98, issue 25, pages 14518-14523 (Dec 4, 2001).

Resources

T. A. McMahon and J. T. Bonner.
On Size and Life.
New York: Scientific American Books, 1983.

R. H. Peters.
The Ecological Implications of Body Size.
Cambridge, England: Cambridge University Press, 1983.

K. Schmidt-Nielsen.
Scaling: Why Is Animal Size So Important?
Cambridge, England: Cambridge University Press, 1984.