What is the Purpose of a Tail in Animals?

Can anyone tell me if they know of any kind of fish that moves its tail in an up and down motion like a whale or dolphin and not from side to side?

I didn't realize that a cat uses their tail to help them land on their feet if they fall. I once had a cat that lost part of her tail when she got in a fight. I thought the tail would grow back but it didn't. She looked kind of funny with half of a tail.

This makes me wonder about the cats you see that have their tails bobbed. Does this prevent them from landing on their feet if they fall?

I live in the country and we often see deer walking across our property. If they are relaxed and not in any danger their small white tail is down. If you see them instantly flip their tail up, you know they sense some kind of danger. When you see the back side of them as they are running away their tail is sticking straight up.

My dog uses her tail to let me know how happy she is to see me. Sometimes her tail is moving so much I wonder how she can stay balanced. She is a big dog and her tail can also be kind of destructive in the house. Anything that is close to her tail can be knocked over if it isn't very heavy.

@cloudel -- If you have never heard a beaver slapping their tail on the water before, I can see how you would be scared. It is amazing how loud that sound can be.

We have a large pond in front of our house where a beaver has built a home. The first time I heard the beaver slap the water with her tail I jumped! Once I figured out what it was I relaxed and was fascinated by it.

Several times when we were sitting out on the deck in the evening we could hear the beaver use her tail as a warning. If I was an animal in close vicinity I know I would not want to stick around very long.

If you ask my dog, he will tell you that cow tails are for pulling! I've seriously seen him chasing cows in the pasture and nipping at their tails.

I know this is dangerous, because he could get kicked in the head. When I catch him, I discourage this behavior, but I have a feeling that it goes on when I'm not around.

He also pulls the tails of my other dogs when they are play fighting. It just doesn't seem like he's playing fair. He has brought a couple of them down by yanking them around in this way.

It's amazing how many horseflies congregate on the back of one horse or one cow. They have to keep their tails going constantly to keep them from biting.

I've used my ponytail in a similar manner before. If I'm being chased by a horsefly, I will just whip my ponytail around in a circle until it leaves me alone. I don't think I've ever actually hit one with it, but it has kept me from getting bitten.

@cloudel – I've also heard that beavers store their fat inside their tails. This helps keep them warm when they're swimming in cold water.

Otters also use their tails in water. They have long, thick tails that they use to steer themselves with as the travel through rivers and streams.

Beaver tails are really useful. They can warn other beavers of predators near the water.

I was frightened the first time I heard a beaver hitting the water with its tail. It was dark, and my friend and I were on a pier over a pond. We heard loud slapping, and we thought that someone was throwing big rocks into the water, but no one was supposed to be in the area but us.

We ran home to her dad and told him about it, and he let us know that it was a beaver's tail that had made the noise. Relieved, we went back to try and find the beaver, but it had already left the area. I guess it may have perceived us as a threat and warned all the other beavers to flee, too.

I think that in reptiles such as crocodiles and dinosaurs, part of the tail contains the muscles that move the thigh backward when running. The mammalian tail does not seem to have this function.

In birds, the tail can work kind of like the T tail on the back of an airplane, in that it provides balance and aerodynamics as they fly.

The shape of the tail can also be used for identification, although of course they don't have the tail numbers like those painted on an airplane's T tail -- you just have to rely on the shape and silhouette of the tail for identification purposes.

When a lizard loses it's tail section as part of its defense mechanism, do they always grow it back, or is it kind of a one-time thing?

I've always wondered about that, because if it doesn't grow back then that seems like a fairly inefficient means of protection.

Also, when the tail section comes off, does is bleed? Because if it does, wouldn't that just lead the predator to the lizard by making a trail?

Do any lizard experts out there know?

Did you know that there's actually a fish with three tails?

It's called the Atlantic triple tail, and has three rounded fins, which leads to it's distinctive "triple tail" look.

Like other fish, they use their "tails" for movement and thrust in the ocean.

However, their three fins also serve as part of their unique defense mechanism, in which they lay over on their sides near the top of the water, so that they look like a group of floating leaves or debris.

Just another use for a tail, I guess!