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> The shark's longevity probably arises because > it expends very little energy, owing to its cold > body temperature and enormous size, Bushnell says
by runeks 10y ago
> The shark's longevity probably arises because
> it expends very little energy, owing to its cold
> body temperature and enormous size, Bushnell says.
Why would either a low body temperature or a large body size contribute to expanding less energy?
- protomyth 10y agoBergmann's rule https://en.wikipedia.org/wiki/Bergmann%27s_rule https://en.wikipedia.org/wiki/Bergmann%27s_rule The earliest explanation, given by Bergmann when originally formulating the rule, is that larger animals have a lower surface area to volume ratio than smaller animals, so they radiate less body heat per unit of mass, and therefore stay warmer in cold climates. Warmer climates impose the opposite problem: body heat generated by metabolism needs to be dissipated quickly rather than stored within.
- akiselev 10y agoYes. Since the volume of an organism increases with size faster than the surface area, larger animals are far more effective at retaining their body heat (greater volume stores more heat while a small surface area dissipates less heat). This in turn means less metabolic activity which means a longer lifespan based on our research of caloric restriction and it's impact on human longevity. However, there are much bigger animals that don't live anywhere near as long so this is unlikely to be a significant contributing factor.