Rodent Evolution

[*Jess♥]

You draw too?

yeah, i like to play with different animal shapes, like this.

not much detail in these though. they were quite quick.

[Tales]

This is a wing design which allows the creature to walk, run and fly.

[*Jess♥]

that's pretty cool! I look forward to see how it turns out.

[Tales]

Basically I need to find a good design for my flying rodents that are unique to the story.

The one problem with flying animals is that most of them are clumsy whenever they are on the ground.

Here's an abtract from the pterosaur article

""But using all four legs, it takes less than a second to get off of flat ground, no wind, no cliffs," he said. "This was a good thing to be able to do if you lived in the late Cretaceous period and there were hungry tyrannosaurs wandering around."

"Birds use legs to launch, wings to flap. They don’t get launch power from wings or flight power from legs. In fact, when a bird is aloft, its legs become payload, or cargo. The muscle on the two back limbs that provides the power to launch must be carried and therefore limits size. Released of that handicap by employing all four legs to launch, giant pterosaurs could fly despite the fact that they were roughly the same size and shape as modern-day giraffes."

http://www.4shared.com/file/101514190/5726...g_design_3.html

http://dc146.4shared.com/download/10182149...ntDownload=true

[*Jess♥]

you could look at flying squirrels?

let's face it, any animal that is adapted to be good at one thing, is gonna have to sacrifice something else.

when you throw out rules of economy you go into hte realms of fantasy.

I can thik of ways that a rat could evolve to be good at both running and flying. things such as small muscle structures in hte wings... these could pull hte membrane to lock it tight to hte limbs while moving on hte ground. almost like how our mouth is controlled.

the problem here is that any muscles that have to be a certain size in order to both run and then fly, you are gonna have to find a way to also reduce the mass and i don't know if this is at all viable.

energy expenditure would be a real issue methinks.

[Tales]

well based on the design in the earlier reply which one do you think would look out of this world at the same time, functional.

[*Jess♥]

I think if you somehow mix the rat with hte pterosaur and a bat, you would get something workable.

rats are pretty good on teh ground, but you need to keep their configuration somehow in order to let them run the same as they normally do.

in that case, you can sacrifice one phalange for the wing like teh pterosaur and keep the rest the same. you can attach the membrane to hte rear leg like teh bat.

in terms of muscle structure... you'd have to adapt the skeleton and muscle structure like that of a bat since a rat cannot pull it's forelegs out horizonatally.. I think.

[Tales]

what do you think of Config F and E

Config F have the 3 middle fingers having fingers to climb trees and also walking.. It won't win any olympic medals like rats but it serve to aid the hind legs to help the creature to jump from the ground

Edited April 28, 2009 by Tales

[*Jess♥]

in terms of aerodynamics and flight mechanics, I do not think it would work.

I think you need a pretty solid leading edge, otherwise you will have all sorts of turbulence cause by the skin flapping about.

with such turbulence you can't generate lift.

also, I think it unlikely that any type of evolution would yield two extra bones coming from hte elbow joint.

[Tales]

Here's config G

[*Jess♥]

yes. G is certainly better.

I'm still a little puzzled about the structures you have coming from the elbows though.

well I drew my idea of what would be a sensible shape.

although in this drawing, the neck is too short.

i couldn't be bothered using my scanner but the quality of my camera is good eough for the detail in this drawing.

[Tales]

Okay guys I have a problem with my flying rodents...

Do you think it's wise to have fur over the wing membranes? this is becos, I want some of my flying rodents to be able to survive in the colder areas of my islands which have a mountain range. They have a special rete mirabile that helps with heat conservation in the wings but I just wanna to be safe.

Does this sound ok?

Edited May 19, 2009 by Tales