Bats and Pteradactyls

When looking at bats and pteradactyls I notice how much their wing design hinders ground movement making them effectively helpless when they land.
I must wonder if that is one of the primary reason pteradactyls died out in favor of birds and why bats seem to operate in fringe niches compared to birds.

Welcome Jabberwqocky. I’ll point out that General Questions is meant to be restricted to questions with a factual answer. I don’t see any question at all in your post, but I’ll try to address the implied question.

Bats are certainly hindered when moving on the ground, although probably not as much as you might think. They are certainly a long way from being helpless and numerous species of bats routinely hunt on the ground. Some pterosaurs were also hindered while on the ground, just as some bird are, but it’s still open dispute whether all were. It’s believed that some species may have been quite agile runners.

The fact that bats are less mobile on the ground or in the water probably is the major reason why they have radiated much less from the original form than birds have. However the relatively fragile nature of the membranous wing almost certainly plays a role as well. Although bat wings heal amazingly fast they are still in constant danger of tearing if a bat is operating on the ground in rough terrain, and they pose a risk of infection as well as requiring energy to repair. That probably contributes significantly to the inability of bats to become true terrestrial animals ever again.

But I have some problems with some of the points you made.

Pterodactyls didn’t really die out in favour of birds. The two taxa shared the skies for millions of years quite happily and for part of that time the bats were also operational… The pterosaurs seem to have died out for the same reasons that the dinos and icthyosaurs and a whole range of other species died out. Whatever that may have been it had nothing to do with the birds. You might jus as well say that pterosaurs died out in favour of dolphins or bats or coyotes or even people, all of which would be competing for some of the same food sources today.

Bats don’t really operate in fringe niches. They are the primary aerial insectivores over most of the planet for half the time, that’s hardly a fringe niche. I would consider something like a koala as occupying fringe niche since it exploits a resource that no other species ‘wants’ to utilise and it does so in an unusual way. Bats in contrast are exploiting a resource that thousands of other species, including many birds, would benefit from exploiting but are unable to, and they do it in a very straightforward manner.

Bats also operate in a surprisingly wide variety of niches. While most people think of bats as nocturnal aerial insectivores there are also a great many bats that are frugivores, bats that are nectivores, bats that are piscivores, bats that are parasites and bats that are out-and-out carnivores preying on frogs, reptiles, small mammals including other bats and even birds.

I would accept that bats operate in a somewhat restricted niche in that they are almost exclusively nocturnal, but that’s not really a fringe niche since it accounts for 50% of the time on the planet. You might just as well say that cats occupy a fringe niche for the same reasons.

It’s also a little doubtful whether you can validly compare bats to birds in that way in the first place. Bats are fairly small order while birds are one of the larger orders. It seems to me you’d be about as justified saying that elephants operate in fringe niches compared to carnivores because all elephants are terrestrial, tropical herbivores while carnivores are terrestrial and aquatic, are found world over and run the spectrum form pure carnivore to true omnivores. Carnivores may have evolved to fill more niches but really there’s way to make a fair comparison between three elephant species and all the bears, cats, dogs otters etc, in the world. In the same way there’s no way to effectively compare 1000 or so bat species with 10, 000 birds species. Even if they were, the fact that birds have evolved to occupy more niches is scarcely evidence that bats occupy a fringe niche.

First off: the name of the group is “pterosaur”. Pterodactyls were but one kind of pterosaur.

There is also a fair amount of debate as to whether pterosaur wings were really all that much of a hinderance to their ground movement. The general consensus is that pterosaurs likely evolved flight from the “ground up”, as none possess any significant arboreal adaptations (there is also some debate as to exactly where the trailing end of the wing membrane attaches; some feel that the “bat-like” attachment to the thigh is incorrect, and that the uropatagium-like membrane between the legs and tail may have not been present). If so, then at the very least they would have been unhindered on the ground in the early stages of their evolution. It is worth noting, however, that pterosaurs were not capable of folding their arms up as tightly as birds can.

Not quite. The earliest bat fossils we have are only 50 million years old, whereas the demise of pterosaurs occurred 65 million years ago. Granted, those earliest bat fossils show bats in more or less their current form, but we have no evidence that they actually arose 15 million years or more earlier than that.

Birds and pterosaurs did, however, share the skies for about 90 million years (with pterosaurs being the older of the two groups by about 100 million years), indicating that at least initial bird design did not prove sufficiently superior to that of pterosaurs to drive the group into extinction.

Bats and birds overlap, and birds and pterosaurs overlapped, but we have no evidence of all three existing at once.

Ichthyosaurs died out well before the K-T event, actually – about 90 million years ago.

Fair cop. I was going with the commonly accepted belif that bats and ptreosaurs shared the skies. You’re right that their is no hard evidence for it.

See that’s why I come here. I learn things from the smart people.

Just thought I’d return the favor, given my earlier confusion about “reproductive age” :smiley: