Why a bat is the only flying mammal? - (Dec/04/2007 )
Mammals are the most advanced but yet we're not diversed enough to have more flying species..
Why is that?
we have gliding mammals.
perhaps there was no need for mammals to "fly" long distances.
What do you mean " most advanced", all organisms are equally advanced. Don't be fooled by this common misconception. Every living organism is by definition the result of being the most fit for a particular environment, for example on the island of Komodo lizards are the top predators, not mammals, sharks (cartilaginous) are top predators in many marine environments, not dolphins or fish (bony), which are both more recent.
However, some organisms appear to retain some "primitive" characteristics, leading to them being lower down on "evolutionary trees" which are purely a mathematical model of the number of changes made to the characteristics being studied, more changes = longer branches. This commonly is misinterpreted as being more advanced rather than the better interpretation of more changed.
Anyway, to answer the question... birds and insects had filled most of the niches already and therefore could outcompete the mammals.
Basically there is no second place in Nature. An organism is either the best in its nich or extinct.
Quite likely (and this is only my guess) bats evolved in an evironment, where birds were missing, or (more likely) somehow less efficient at exploiting their environment. Notice how all bat species are nocturnal. Very few birds are actually active (feeding) at night. A niche made less competitive by dayhours.....
Perhaps, there is no second species of truely flying mammals because there is no free niche available and animals living there now are just too good for a relative new comer to enter and displace.
I keep jumping off cliffs, but my DNA refuses to change and grow me some wings....
Consider the anatomical changes that would need to happen to allow for flight. Speaking as a non-anatomist, I see that we have two models, possibly three, in vertebrates: birds and bats (and possibly the flying foxes as a third model, which are more closely related to dogs than the "true" bats). It is one thing for a gliding mammal to develop strong membranes between their bodies and their arms, but their musculature and skeleton would also have to change fairly dramatically to allow them to shift from (energy-neutral) gliding to energy-intensive flapping.
As a top-of-the-head guesstimate, I'd say that the intermediate anatomical forms are not sufficiently advantageous enough to allow room in the niche, so even if one or two adaptations did evolve, the new animal still wouldn't make the grade.
I guess, flying animals could not become dominant forms due to severe size limilation they can reach.
yes, limitations of food in today time and geology. The Quetzalcoatlus was plenty large. Just imagine, if mammals had grown up during times of shallow seas, mild climates and elevated oxygen levels (O2 level have gone as high as over 30% - during the carboneferous period... possible cause for the rise of giant insects of that era... dragonflies the size of a seagull.)
if i drop kick a hamster does that count?
May I add that the birds were flying before the mammals had even begun to evolve into different ways. So the "air" niche was probably already taken by the "reptilian birds" (birds ancestors), leaving no real places for any flying mammals.