Why do equines have tails?



Why do equines have tails?

In: Biology

They are not detrimental to survival so no reason to disappear. They might even be useful to survival as they are generally used for swatting flies, expressing emotions and might serve as a fitness signal to potential mates.

From the Wikipedia page “Tail (horse)” –

The tail is used by the horse and other equidae to keep away biting insects, and the position and movement of the tail may provide clues to the animal’s physical or emotional state.

Also, the evolutionary ancestors of horses had tails, and there hasn’t been any environmental pressure that selects for lack of tail.

The tail is meant as leverage for running at high speeds and brushing away insects. Those who survived insect stings and bites which were venomous, and those with shorter true tail bones than hair length outlived those without such features; these evolutions have given us the horse we see today, with its long haired tail and shortened tailbone.

Apart from the evolutionary stuff, modern horses were selectively bred to be useful to humans. Horse tail hair was useful (and still is for some niche applications) so it was worth keeping hairy horses around.