Why do rabbits prick up their ears when they are running at full speed?

Have you ever seen a rabbit running at full speed? Rabbits who usually stop and jump with their ears upright after jumping are surprisingly fast when they run all the time. It is said that rabbits can reach 70 kilometers per hour when they are chased, which is much faster than giraffes with slender legs.

Strangely, when running at full speed, the rabbit's ears are upright. If you are exploring the enemy's residence and judging whether the enemy is close to you, it is of course easier to prick up your ears and find out. But when being chased, now that you know your situation, you don't need the radio function of your ears so much. Long ears are subject to greater air resistance, which will affect the running speed.

So why did the rabbit prick up its ears at this time?

It turns out that for rabbits, it is when they are doing strenuous exercise at full speed that they need to erect their ears, because rabbits rely on two long ears to radiate heat. People sweat, dogs breathe by sticking out their tongues, and rabbits keep their body temperature from getting too high by radiating heat from their ears. Of course, the function of long ears as a sound collector is also excellent, but it doesn't have to be just a long strip as a sound collector. The long shape is to let the heat radiate from the upper part as soon as possible.