Habitat overview
Why can mammals adapt to so many different habitats?
From the coldest arctic ice to the hottest deserts you will find mammals living and thriving. There seems to be no climate that they can't adapt to, however changeable it may be. There is a good reason for this - mammals have the ability to keep their body at a constant temperature whatever the weather. They are 'warm-blooded' (endothermic).
Mammals achieve this feat by chemically 'burning' their food as fuel inside their bodies. This is kept under tight control by a region of the brain that acts like a thermostat, and this makes sure that the mammal's body temperature stays about the same.
A constant body temperature is a great advantage for mammals because all the chemical processes that go on inside a living body tend to happen more slowly at low temperatures and faster at higher temperatures. Mammals can regulate their temperature at an optimum for all these processes, allowing them to be active at very cold or very hot periods and to keep up strenuous activity for a long time. Animals such as lizards rely on moving in and out of the warm sunlight to regulate their body temperature. They slow down when they can't warm up and may die if they can't get away from heat. They also tend to overheat quickly when they are active as their muscles produce warmth.
Using chemical (food) energy to keep body temperature constant is expensive, and since mammals need to be efficient at keeping the warmth they generate inside themselves, they often have fur and a layer of insulating fat beneath their skin to prevent heat from escaping. To help lose heat when they are too hot, they have sweat glands that take the heat away from the skin through evaporating water. This means, though, that they need to drink more than other animals.
