A rat’s tail has other uses besides helping with balance. Rats regulate their body temperature with their tails which serve as heat loss organs.
The tail contains many blood vessels, especially at mid-length and tip which help keep their body temperature at the right level. The process is called thermoregulation.
If body temperature rises, the blood vessels swell pushing them up towards the tail’s surface so that the temperature of the blood is reduced. The cooled blood can then flow back through the body, lowering its temperature.
When body temperature drops, the blood vessels in the tail shrink (vasoconstriction), carrying less blood flow to the tail and thus conserving body heat.
While a rat’s tail makes up only 5% of its body area, it controls 17% of body heat.
Rats that have lost their tails have more difficulty regulating body temperature. Body temperature rises higher and takes longer to cool down.