Thread: Differences between bats and birds

I have observed some of the differences between the behaviour of bats, and that of birds. Where birds sit on branches, bats hang underneath it. A bat can sit on top of a branch, but it doesn't do this because of added balance difficulties. But the real question would be, why birds try their best to sit on top of a branch, while they could just hang underneath it.

As far as i know, a bird would have no disadvantages from this behaviour, and would need less balancing. Thus it would be able to do more, with less energy.

A bat can not fly up side down, neiter can a bird, though a bat can sit on top, or hang under a branch, easily. While a bird will try to keep balance on top.

This would mainly be the case for small birds, obviously. Why is there no species of birds that present this behaviour.. Something to do with digestive system?

Two thought's occur here, though how correct they might be is any one's guess, firstly that bats use echolocation to give them a picture of their enviroment so they are not as reliant in needing a good field of vision in order to feel safe, where as birds are far more reliant on hearing and sight. This would mean that it's easier to survey the enviroment from on top of the branch rather than from hanging under it.

Thought number two is that birds find it easier to balance on top of the branch because of the way their wings fold and are not so subject to the stresses of gravity that would effect them much more when hanging upside down.

Birds have, in gross general terms, the wrong anatomy and morphology or it. They have very very keen sense of balance, so why should they hang, it imparts no benefits to them

The order of birds that sit on branches most is the Passerines. They have a built in mechanism for gripping the branch. If they slip forwards or back, tendons increase the grip of claws around the branch. This happens automatically without extra energy expenditure. So they sit on branches very securely without wasting energy. A bat cannot do that.
Passerine - Wikipedia, the free encyclopedia

There's no reason to assume that someday a bird might not evolve to hang from a branch instead of perch. But it would appear as though there were no biological imperatives which caused them to do so. Given that there is ample space in a tree to sit, they had no reason to hang. In addition, it probably disguises them from predators better to sit on top of branches rather than hang like brightly colored fruit.

Bats seem to have evolved the hanging technique to deal with life in caves where there is no surface upon which to sit except the cave floor and perhaps the random ledge or outcropping. It just made more sense for them to maximize their living space by hanging from the ceiling.

And there's reproduction to consider. Baby bats cling to their mothers after being live born and can suckle no matter which way up mum happens to be hanging from the ceiling. Birds have to have a safe place for eggs to be laid and to be hatched. Nestling birds have to fight each other to get their heads up for the first, best serves of food from both parents.

Well, i get how evolution went the way it does, it just seems weird that all bats hang upside down, and all birds sit on top. I mean there is such an diversity among birds that one would assume there should at least be one species that hangs, or can, an sometimes will hang from under a branch.

I have read into this (some opinions, etc, nothing sourced), and i think it's because of their ancestry. As birds have evolved from a predator dinosaur, like the raptor, and they would have no use for upside down navigation. But the ancestry for bats are tunneling mammals, and they would have been upside down in their tunnel at some times. Maybe this is what drove eiter in their direction. A birds head even rotates whenever the actual flying bird makes an upside down air acrobatic. So maybe a bird's brain is actually 2 dimensional (even though they fly), and a bat flies 3 dimensional..

Any thoughts about this?

Any thoughts about this?

Well. What thoughts do you have about egg laying, sitting, hatching and feeding the young. If birds were to hang upside down for sleeping, that still wouldn't solve the reproduction problems. (We know that some small birds make hanging nests, but the process is much the same as all others from that point on. )

Also, birds have a need to keep their feathers in proper alignment for flight at a moment's notice. A chicken held upside down looks like it takes an effect to keep its feathers in proper order (if at all possible), and rain probably makes the problem much worse by getting in between the feathers and soaking them.

Bats can live in sheltered/darkened locations because of their echolocation abilities, and the shelter negates most concerns about having to take flight in an emergency and about getting soaked by rain while hanging upside down (besides, they don't have any feathers).

Unless you can think of a valid reason why a bird which can hang upside down on a branch would survive more successfully than a bird which perches, I think you have your answer.