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Comment by dragosmocrii | Hacker News Reader

My opinion: long mammals like cows, horses, camels, etc can't reach their behinds with their limbs. They can use their head (especially when the tail doesn't reach the fronter part of the behind), but it's not efficient because their head is heavy (and they're heavy animals in general) and has more inertia. Therefore, a tail is their swift efficient defense for the behind.

By contrast, smaller mammals like cats, dogs, rats, etc, don't use their tails to deter insect, because they can easily jump, move quickly, or smash their head into their body, because they are much lighter.

Now, this makes me wonder, why do cats and dogs have tails. Maybe im the case of cats it is for equilibrium, but dogs? I think dogs use tails to show people when they're excited :)

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Look at what the cat's tail does when it leaps through the air, or the dogs tail when turning a corner at high speed, and it will become clear. It's for balance and agility.

Greyhounds and Cheetahs naturally have fairly long tails.

Can we call a greyhound's tail natural, if it has been bred for purpose by people?

I would as they where bread for speed not looks, with the tail evolving based on selection pressure.

Can you call any domesticated animal natural?

Sure, it's not a terrible stretch. An external force (us) encouraged their shaping through selective pressure. We are from the environment, the same as a rift valley or other long term environmental impact, for domesticated animals. As far as I know little to none current domestication uses fully manipulative method like CRISPR.

That we semantically look at our own involvement as somehow different on outcome isn't really the intent of artifice, I think. Rather that humans, individually and collectively, modify the environment to suit their needs.

I'm not really looking to argue the point, but interested in hearing other's thoughts on this.

It’s a legitimate question but it's a slippery slope. A wild horse can be domesticated, is it natural? Donkeys, and camels too, even birds like parrots and raptors can be trained to do work and be subservient to humans.

If the question is learned behavioral domestication vs bred genetic domestication... Is a banana natural? Apples oranges grains, virtually every verity of produce at the store has been ’domesticated’. Are they natural?

Humans have been bred for group behavior, language and manual (slave) labor by means of evolutionary pressure and natural selection. Are we unnatural?

Pretty sure ‘natural’ is not the delineation we want to use

Do not conflate taming/training (of an individual) with domestication (of a species). Very different things.

I saw a lemur (in a zoo) without a tail once — it couldn't jump.

It the case of labrador retrievers, those without a tail have an extremely difficult time swimming, whereas those with a tail used them to provide propulsion and steering.

The tail in dogs is fairly important for communication (especially with other dogs - intraspecific communication), as it can indicate many different emotional states, not only excitement. See for example https://www.mdpi.com/2076-2615/8/8/131/pdf https://www.dogways.info/how-dogs-communicate and https://www.psychologytoday.com/us/blog/canine-corner/201112...

This is another reason why cutting the tail is wrong - besides the fact that it's cruel (it's almost incredible now, but it was common a few years ago, and it is still practiced in some countries).

Showing someone (or another dog) that you're excited or scared ("tail between his legs") is a very potent social mechanism I think. I don't think it adds much to the motor skills of the dog, besides maybe giving it a tool to keep flies and insects away from the ol' pooper.

Watch something like a greyhound or German Shepherd at full throttle and you might reassess your view about whether it adds to motor skills. It seems to be a very active part of a full speed sprint.

It's also a very subtle tool for social interaction as you note - the difference between tail wagging whilst up, horizontal and down, or wagging just the tip and so on. There's quite a lot of complexity hiding there.

Anatomical features often serve multiple purposes. Scent glands in many animals are evolved out of pre-existing features. We talk and chew with our mouths. Etc.

To put it more bluntly, the obvious difference is that cats and dogs can lick their private parts. Cows and horses can't perform the same level of personal hygiene while also providing more surface area for insects to invade.

I wonder whether this is not really more about infestations than bites.

Horses tend to kick if they're trying to get at something behind them.

According to a quick internet search, dogs have tails for the same reason as cats, to help with balance and inertia when running.

you're right, they do kick. they also can shake their skin.

i was thinking more in terms how people or primates can use their hands or feet to basically reach all parts of the body, while cows/horses cannot to the same degree.

With the prevalence of trails, my guess is there is just some cost to removing the trails, genetically. Some evolutions paid the cost, some didn't. Even among animals that don't really need the tail for anything.

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