They could climb?

[arc]

Except we see fiberous type feathers not suited for flight further back in the evolutionary lineage. So it's doubtful that these types of feathers helped much in terms of air time.

 

http://people.eku.edu/ritchisong/feather_evolution.htm

 

But now few examples in flightless birds?. I do think the penguin's front flipper gives a nice example of scales to feathers over its surface, from leading edge to the back, a nice example of the development of flight technology, in reverse of coarse, but a smooth transition if so interpreted.

Edited September 3, 2013 by arc

[TransformerRobot]

Another thing about Velociraptor I just thought of:

 

Did they live anywhere besides Mongolia?

[arc]

IIRC flightless birds tend to have feathers that would be able to fly for at least part of their life, but they tend to lack the keeled sternum and other attributes of flying birds. Primitive feathers were a single hair-like filament then branched out into the leaf looking structure, as well as other feather types, of modern aves.

 

 

Just like how even flightless birds have feathers, right? I've seen emu up close and their feathers are almost furry looking, and not so much for flight.

 

Well, it looks like there is not a consistent sequence to these feathers. Ringer and Moontanman have furry feathers for insulation preceding flight feathers. But current flightless birds have furry feathers after flight feathers. Penguins, also a flightless bird, have gone back to the beginning with flippers showing scales or something similar gradually elongating into feathers over the flippers leading edge. I think we can agree reptilian skin with scales was at some point the beginning.

 

It appears to me this base structure can change in a variety of ways, based upon evolutionary need. If this is how an avian ancestor dealt with cooling climates or migration then that seems logical. It obviously evolved sooner or later into flight. But the example of the penguin may show this as not needing to be confined to a particular sequence or evolutionary direction.

 

These things are the Swiss army knife of adaptation.

Edited September 4, 2013 by arc

[overtone]

This chasing and jumping behavior would give advantage to the fastest and highest leaping, leading to the physiology of extremely fast bipeds that catch prey on the fly.

 

The arms and tail would show in following generations the slow adaptation to the gradually extending glide times. Spreading the forearms apart increases balance and control in the air.

Early scale-modified feathers would slow them down, drag on the leaping, and also interfere with the deftness and manipulation they need.

 

Gliding and running/leaping requirements are in opposition. Also, we see animals adapted for gliding - they don't have feathers or anything like feathers. Birds that glide are not early stage or primitive - the ability to glide with agility seems to be a later and more sophisticated specialty rather than a primitive fore-runner.

 

Cliff nesting and so forth is not a rare and specialized situation - it's among the commonest of bird practices.

In particular, it's a common practice among birds that breed and feed near water - and near water environments provide obvious selection pressures for bipedal walking among air breathers, a fairly rare innovation among the genetic lines extant on this planet.

Edited September 4, 2013 by overtone

[TransformerRobot]

I still would like to know where else Velociraptor lived.

[Moontanman]

I still would like to know where else Velociraptor lived.

 

http://en.wikipedia.org/wiki/Velociraptor

 

 

 

It would appear that the main species only occurred in Asia but Utah raptor which is a larger version did live in North America...

[arc]

Early scale-modified feathers would slow them down, drag on the leaping, and also interfere with the deftness and manipulation they need.

 

Gliding and running/leaping requirements are in opposition. Also, we see animals adapted for gliding - they don't have feathers or anything like feathers. Birds that glide are not early stage or primitive - the ability to glide with agility seems to be a later and more sophisticated specialty rather than a primitive fore-runner.

 

Cliff nesting and so forth is not a rare and specialized situation - it's among the commonest of bird practices.

In particular, it's a common practice among birds that breed and feed near water - and near water environments provide obvious selection pressures for bipedal walking among air breathers, a fairly rare innovation among the genetic lines extant on this planet.

 

The move from four legs, that currently all legged reptiles including those that climb posses, to a two legged bipedal stance, is marked by more than anything else, a vastly faster and more efficient mode of transport. Currently a wide variety of birds continue this behavior of running to chase prey, to take flight or as flightless species such as the ostrich or emu to run from predators.

 

Two legs is not a climbing physiology. Most climbing reptiles have, besides their four legs, a low center of gravity. It is difficult to imagine a taller bipedal with a higher center of gravity changing from a running adaptation to a climbing. It just doesn't fit the mechanics. The comparison to other glide adaptations does not take into account that they are low, four legged with grasping front limbs ideal for climbing such as in flying squirrels.

 

The bipedal proto bird would be of such awkward disadvantage on steep terrain to four legged climbing predators (remember they don't have flight yet) that an adaptive change should address these difficulties. One such as lowering the center of gravity.

 

Lets imagine a four legged reptile with feathered limbs running down the steep hill sides where it lives to flee from predators. Is this a proto bird, the flying squirrel of reptile adaptation. An important point is that the squirrels just jump and glide, flying squirrels do not need to run to take off. So why would a bipedal runner be on the side of a cliff jumping off?

 

Now imagine a reptile that evolved to a none climbing biped, an extremely fast runner, which by the way prepares the cardiovascular for the demands of flight. Its diminutive or at least reduced forward limbs, no longer needed for traction, are more often now used as balance when leaping for prey.

 

I believe the pursuit of prey drove this running, pursuing flying insects eventually lead to flight. The road runner (Geococcyx californianus) resembles what I would imagine the early adaptations resembled. They are considered weak flyers yet run at speeds as high as 32 km/h (20 mph)

 

Does this road runner look like a climber? Does it resemble its earliest ancestors?

[TransformerRobot]

No it doesn't look like it could climb, but it sure looks close to Velociraptor.

 

Anyway, where else did Velociraptor live besides Mongolia?

[arc]

No it doesn't look like it could climb, but it sure looks close to Velociraptor.

 

Anyway, where else did Velociraptor live besides Mongolia?

 

Moontanman

Posted 4 September 2013 - 05:19 PM

It would appear that the main species only occurred in Asia but Utah raptor which is a larger version did live in North America...

[TransformerRobot]

What if there are chances of of Velociraptor being in the Middle East or Africa at one point, but they weren't there long enough to die and get fossilized?

[arc]

The more successful a species the greater the chance of finding remains. But size matters, big bones do not get scavenged at the time of death and resist the forces of time and geology much better than smaller and lighter bones would. Other animals, wind and more importantly water scatter smaller remains over wide areas.

 

The ancestors to birds show the gradual development of hollow bones, which makes them lighter and more fragile, leading to greater dispersion by surface water and wind.

 

The specimens found indicate rapid burial in a sandy terrain, conserving the largely complete remains in a probably quite rare circumstance. This to me does not indicate their limitation to a small geographic area, only that their remains, due to their characteristics, are quite easily erased by time and geology.

Edited September 7, 2013 by arc

[TransformerRobot]

The more successful a species the greater the chance of finding remains. But size matters, big bones do not get scavenged at the time of death and resist the forces of time and geology much better than smaller and lighter bones would. Other animals, wind and more importantly water scatter smaller remains over wide areas.

 

The ancestors to birds show the gradual development of hollow bones, which makes them lighter and more fragile, leading to greater dispersion by surface water and wind.

 

The specimens found indicate rapid burial in a sandy terrain, conserving the largely complete remains in a probably quite rare circumstance. This to me does not indicate their limitation to a small geographic area, only that their remains, due to their characteristics, are quite easily erased by time and geology.

 

So they could have gotten somewhere far beyond Mongolia and China, but after they died their remains didn't stay in place long enough to become fossils?

[arc]

 

So they could have gotten somewhere far beyond Mongolia and China, but after they died their remains didn't stay in place long enough to become fossils?

 

They need to be covered quickly, such as blowing sand or even a collapse of a sand cliff to secure their survival through the ages. All of the current examples look to have been in sand shortly after their time of death.

[TransformerRobot]

In other words; no, they were not.

[arc]

I believe it is possible. Only time will tell if other fossils will be found in other geographic locations. For a specimen that only weighed 13-18 kg (30-40 lb) and was around 1.8 m long, it is remarkable that any piece let alone an almost complete specimen would survive from the Late Cretaceous (85 million years ago).

 

As a comparison australopithecus-africanus stood an average 138 cm (4 ft 6 in) for males and 115 cm (3 ft 9 in) for females. Their weight averaged 41 kg (90 lbs) for males and 30 kg (66 lbs) for females.

They only lived around 3.3 to 2.1 million years ago yet just a few partial remains have been found.

More than 80 million years separate these species fossils, yet the oldest are the more complete and better preserved. It seems to me a quite rare occurrence that they have survived so well.

 

[The Tactical Strategist]

Velociraptors are believed to have climbed trees. Their skeletal structure was a lot like a bird, and they sure were light enough to be in the trees, even though I'm sure it spent most of its time on the ground. Feathers? Yes, maybe a down at least, for both warth and mating display. And when it comes to your question on their range, they have been found in Mongolia, but im sure they have been in other places, just not discovered. It's rare to find fossils, and most fossils and dinosaur species will never be unearthed and discovered. I'm sure they were in a few other places. As was was stated, Utahraptor was a North American dromeosaur that probably was a lot like velociraptor, much like other raptors.