crocodiles and lions

[asdfg]

why do crocodiles eat less than lions?

[New Forester]

Because they are cold-blooded, so called. Crocs, like all non-extinct reptiles, are "poikilothermic". This means they cannot generate body-heat, except through muscle activity. They maintain a high, active operating temperature when needed by basking in the sun. If they are too hot they move into cool shade or water. Lions, like all mammals, birds, perhaps many dinosaurs and probably pterosaurs, can produce heat without muscle movement. They can therefore maintain a constant internal body temperature, and can keep active all the time -- they are warm-blooded, or homoiothermic. This makes mammals effective at getting food, running away and doing other activities, but it uses lots of fuel. I think warm-blooded animals consume about ten times as much food as cold-blooded ones of the same size. Note that "cold-blooded" does not necessarily mean cold. A basking lizard could have blood as warm as ours. Bumblebees are warm-blooded while flying (using muscle heat) -- this is why they are furry, and one reason why the "bumblebees can't fly" idea arose. Other large insects too -- large moths must buzz their wings to raise themselves to flying temperature. Honeybees maintain about 30 C in the centre of the hive all the time, even with very hard frost outside. Some active fish, (such as large sharks and I think tunny) shunt warm blood from the muscles to the eyes and brain to improve reaction speed. Some mammals and birds are part-time cold-blooded when resting -- such as bats, young swifts, hummingbirds etc. Many more when hibernating. This is of course to save energy.