Support NeoGAF

[efyu_lemonardo]

Well, yes, this is why a bald eagle is able to grab larger fish by grabbing it in the water going at high speed than it would be able to lift from a dead stop.

But that's a difference of a few pounds, and the bird still isn't capable of flying with even half of its own weight. I doubt Argentavis could have managed much more than 10 - 15 kg. For it to be able to lift more than its own weight would go against everything we know about other birds, and in any event I think the feeding section in the Argentavis page says everything.

What if it were an African Haast Eagle?

Take into account I'm no expert and if anything my approximations are probably too optimistic, I'm just plugging numbers into available formulas, for fun. For all I know there are critical factors that I'm not taking into account.

My post is based on the fact that apparently the largest known wing load in the animal kingdom, belonging to the pterosaur quetzalcoatlus, was just under 20 kg per square meter of wing. And calculations suggest anything above a load of 25 kg per square meter is a physical impossibility for a bird, or presumably anything without some kind of constant source of power like an engine. In addition, I'm assuming that even when the wing load falls within the acceptable range, it's still probably not possible for a bird to carry anything considerably heavier than its own weight.

Having said that, It looks like a Haast Eagle could never carry more than 30 kg even with assisted takeoff and landing. The bird itself seems to have weighed at most 20 kg and had a wing area of no more than 3 square meters, and those are the highest estimates. Argentavis, on the other hand, was over 70 kg and with a wing area of over 8 square meters according to estimates.

edit: I should add that by "assisted takeoff" I mean something like literally being shot into the air by a catapult

 

[Demoncarnotaur]

T.Rex.

Who wouldn't want to see a T.Rex?

 

[DECK'ARD]

What if it were an African Haast Eagle?

I'm glad I wasn't the only who was being reminded of Monty Python by this.

 

[T-Rex.]

T-Rex. Got enough problems with birds shitting on my car atm and I don't need that big fucker dropping bombs on it and all.

 

[NYCmetsfan]

crow because crows are smart and we can be buds

 

[efyu_lemonardo]

Well, yes, this is why a bald eagle is able to grab larger fish by grabbing it in the water going at high speed than it would be able to lift from a dead stop.

But that's a difference of a few pounds, and the bird still isn't capable of flying with even half of its own weight. I doubt Argentavis could have managed much more than 10 - 15 kg. For it to be able to lift more than its own weight would go against everything we know about other birds, and in any event I think the feeding section in the Argentavis page says everything.

I'm learning this as I go, but apparently on average, birds of prey aren't the best examples of what is theoretically possible for a large bird to lift because they seem to be more adapted to agility and high maximum speed which are achieved by being extremely light and having small wing areas for a relatively low wing load.

Having said that, there are birds of prey documented to carry their own weight in flight:

The harpy eagle routinely takes prey weighing more than 7 kg (15 lb).[9] The harpy eagle possess the largest talons of any living eagle. The harpy's feet are extremely powerful and can exert a pressure of 42 kgf/cm² (4.1 MPa or 530 lbf/in2 or 400 N/cm2) with its talons.[38] The harpy eagle has been recorded as lifting prey up to equal their own body weight.[9] That allows the bird to snatch a live sloth from tree branches, as well as other huge prey items. Males usually take relatively smaller prey, with a typical range of 0.5 to 2.5 kg (1.1 to 5.5 lb) or about half their own weight.[9] The larger females take larger prey, with a minimum recorded prey weight of around 2.7 kg (6.0 lb). Adult female harpies regularly grab large male howler or spider monkeys or mature sloths weighing 6 to 9 kg (13 to 20 lb) in flight and fly off without landing, an enormous feat of strength.

Generally speaking though, it looks like water birds are a better example when it comes to wing loading, as shown by the following graph, taken from this study:

Obviously Argentavis wasn't one of these, but like I said I'm just investigating for fun.

Finally, I stumbled across this amusing little clip of an eagle attempting to kidnap a baby, thought I'd share:
https://www.youtube.com/watch?v=Xb0P5t5NQWM

 

[GIANKRATOS]

Bringing back to life the argentavis would be a disaster.

T-rex is also much more cooler.

 

[kswiston]

My post is based on the fact that apparently the largest known wing load in the animal kingdom, belonging to the pterosaur quetzalcoatlus...

Having said that, It looks like a Haast Eagle could never carry more than 30 kg even with assisted takeoff and landing. The bird itself seems to have weighed at most 20 kg and had a wing area of no more than 3 square meters, and those are the highest estimates. Argentavis, on the other hand, was over 70 kg and with a wing area of over 8 square meters according to es

No one can even agree how much Quetzalcoatlus weighed, let alone if it was capable of powered flight, so I wouldn't base calculations on that.

Haast's Eagle was about twice the mass of a Golden Eagle, but had a stalkier build relative to its wingspan. No way a Haast's Eagle can pick up anything close to 30kg, even if it was grabbing the object at full speed. Even with a flying snatch, golden eagles can only carry 3-4kg. They can't take off carrying much more than 2kg. Big Golden Eagles are over 6kg.

Haast's Eagle's size and mass was used to give its talons momentum when kill much larger moa. It wouldn't have to fly off with its much (intact) prey. There were no natural predators on New Zealand to disturb them.

Argentavis was probably a scavenger, and not built to carry prey. I doubt the bird could lift 10kg, let alone an adult.

EDIT: Harpy eagles hunt from rainforest tree tops, and therefore can make use of a verticality that isn't available if you are snatching things off the ground.

 

[efyu_lemonardo]

Argentavis was probably a scavenger, and not built to carry prey. I doubt the bird could lift 10kg, let alone an adult.

EDIT: Harpy eagles hunt from rainforest tree tops, and therefore can make use of a verticality that isn't available if you are snatching things off the ground.

I'm not doubting any of this, and admit I'm allowing myself to exaggerate for fun
I do find it interesting to understand how these numbers are arrived at, besides observing live birds.
edit: Also, when I mentioned assisted takeoff I assumed the initial velocity for the bird plus person to be very large, aka "being shot out of a catapult"

No one can even agree how much Quetzalcoatlus weighed, let alone if it was capable of powered flight, so I wouldn't base calculations on that.

the 20 kg per square meter figure appears to show up for known birds as well, but I haven't been able to find a particular species yet, so for all I know it may be a very small bird.

 

[billy beane]

I'd eat a T-Rex but only if it was pasture-raised and grass-fed

 

[eot]

T-Rex, because that crow never existed. Can't "bring it back".

 

[KidGalactus]

That teratorn (probably Argentavis magnificens) wasn't a giant crow, but more like an enormous condor.

Better idea, let's bring back azhdarchids:

http://blogs.scientificamerican.com...stalking-in-azhdarchid-pterosaurs-challenged/

 

[multivac]

That teratorn (probably Argentavis magnificens) wasn't a giant crow, but more like an enormous condor.

Better idea, let's bring back azhdarchids:

http://blogs.scientificamerican.com...stalking-in-azhdarchid-pterosaurs-challenged/

How does Sherlock get out of this one?! Can't wait for season 4!

 

[Camjo-Z]

Would I rather re-enact Jurassic Park or Bloodborne? Hm, I die in both scenarios, but at least the T-Rex leads to a cooler demise.

 

[kewlmyc]

T-rex, so flying on planes wouldn't become extremely dangerous.

 

[kswiston]

I wonder if a T-Rex would even be able to cope with the 60% reduction in atmospheric oxygen that happened since it went extinct.

 

[NYCmetsfan]

Finally, I stumbled across this amusing little clip of an eagle attempting to kidnap a baby, thought I'd share:
https://www.youtube.com/watch?v=Xb0P5t5NQWM

I believe this was faked

 

[kswiston]

I believe this was faked

It was. The eagle and zoomed out baby are CG. It was done by a group of VFX students in Montreal as a project.

Kids who can sit up unassisted weigh 15-20 lbs. 10-15lb eagles can't pick them up in any scenario.

 

[efyu_lemonardo]

I believe this was faked

It was. The eagle and zoomed out baby are CG. It was done by a group of VFX students in Montreal as a project.

Kids who can sit up unassisted weigh 15-20 lbs. 10-15lb eagles can't pick them up in any scenario.

I see. Then I guess I'll vote t-rex as well

edit: just out of curiosity, where those clips of eagles in spain dragging mountain goats off cliffs and even slightly "gliding" with them also faked?

 

[luffxan]

I feel like the T-Rex is slightly less dangerous....would hate to look up at the sky one day and get attacked by that crow

 

[Mumei]

No one can even agree how much Quetzalcoatlus weighed, let alone if it was capable of powered flight, so I wouldn't base calculations on that.

Haast's Eagle was about twice the mass of a Golden Eagle, but had a stalkier build relative to its wingspan. No way a Haast's Eagle can pick up anything close to 30kg, even if it was grabbing the object at full speed. Even with a flying snatch, golden eagles can only carry 3-4kg. They can't take off carrying much more than 2kg. Big Golden Eagles are over 6kg.

Haast's Eagle's size and mass was used to give its talons momentum when kill much larger moa. It wouldn't have to fly off with its much (intact) prey. There were no natural predators on New Zealand to disturb them.

Argentavis was probably a scavenger, and not built to carry prey. I doubt the bird could lift 10kg, let alone an adult.

EDIT: Harpy eagles hunt from rainforest tree tops, and therefore can make use of a verticality that isn't available if you are snatching things off the ground.

I was under the impression that the most current estimates for the size of the largest azhdarchids was around half of the previous highs? I'm just going off of that Habib and Witton paper (Witton's book on pterosaurs is great reading and has great art by the author, too), so if there's additional detail I'm missing I'd be very interested.

I see. Then I guess I'll vote t-rex as well

edit: just out of curiosity, where those clips of eagles in spain dragging mountain goats off cliffs and even slightly "gliding" with them also faked?

Well, as you said, they're not lifting them; they're dragging them off the cliff and downwards. It's the same way that there's a difference between the size of an object you could toss over your head versus the size of an object you could push off a ledge.

 

[Theonik]

Big-ass crow you lead to our extinction. T-Rex is a joke.
So T-Rex as the lesser of the two threats.

 

[Bluekaveli]

Brendan Lee

 

[NYCmetsfan]

I see. Then I guess I'll vote t-rex as well

edit: just out of curiosity, where those clips of eagles in spain dragging mountain goats off cliffs and even slightly "gliding" with them also faked?

I think stuff like that is real, just thr bird generally don't screw with humans

 

[kswiston]

I was under the impression that the most current estimates for the size of the largest azhdarchids was around half of the previous highs? I'm just going off of that Habib and Witton paper (Witton's book on pterosaurs is great reading and has great art by the author, too), so if there's additional detail I'm missing I'd be very interested.

Yeah. I remember reading about Quetzalcoatlus having a 50ft wingspan when I was a little kid in the 80s, but I think recent estimates suggest that pterosaurs max out at 30-35 feet.

That article makes a good point about physiology though. Pterosaur wings are anchored differently than bird wings and having a continuous membrane rather than interlocking feathers probably makes a difference as well.

 

[ChubbyHuggs]

Whichever tastes more delicious.

Eating crow is never delicious. Especially on NeoGAF.

 

[nampad]

I don't like crows so the T-Rex wins by default.

If I can chose freely, some animal we wiped from this earth because it was so delicious.

 

[efyu_lemonardo]

Well, as you said, they're not lifting them; they're dragging them off the cliff and downwards. It's the same way that there's a difference between the size of an object you could toss over your head versus the size of an object you could push off a ledge.

I didn't mean to say they were lifting them, but rather that (as seen in this clip between 5:00 and 6:00) since those glides are shown to start from a very low velocity (which corresponds to the very sharp initial angle of descent) and later on seem to descend more gradually as velocity increases, that a high initial velocity achieved through an assisted launch could have a better lift to drag ratio.

A better example is this clip of a harpy eagle hunting a sloth.

You're absolutely right that it should be called gliding rather than flying, though.

 

[c-murph]

i don't know... The crow I guess. T-rex seems like it be too dumb. We do need something to rival humans. We got no competition any more. It's boring.

 

[Mumei]

Yeah. I remember reading about Quetzalcoatlus having a 50ft wingspan when I was a little kid in the 80s, but I think recent estimates suggest that pterosaurs max out at 30-35 feet.

That article makes a good point about physiology though. Pterosaur wings are anchored differently than bird wings and having a continuous membrane rather than interlocking feathers probably makes a difference as well.

It should also be noted that Witton and Habib point out that the azchdarchid humeri are such that they could launch an animal as high as the high-end estimates of 500 kg, even if 200 - 250 kg is better supported by what we know. It's even predicted that they could take off from a floating start (e.g. if one landed in water), which would be a sight. Witton also has a post on his blog that talks about some of these issues in a more layman-friendly way:

Giant azhdarchids did not suffer from flight power shortages

Many internet commenters often roll out the idea that giant azhdarchids would struggle to take off from the ground, even allowing for new ideas like quadrupedal launching. These folks need to get out of their armchairs, however, and check out some classic work on animal flight and giant pterosaur takeoff. James Marden's 1994 work on animal takeoff found some surprisingly consistent scaling trends among animal flight power and takeoff ability, allowing us to predict the muscle power of even long extinct fliers like Meganeura, Archaeopteryx and a 10 m span azhdarchid. The resulting aerobic power output of azhdarchid flight muscles - all 60 kg of them (a fairly safe bet for a 250 kg azhdarchid given what we know of animal flight muscle fractions among modern fliers) - is a bit rubbish, only 4.52 N/kg of body weight. Animals need to be generating 9.8 N/kg to fight gravity, so this would seemingly ground our giants. Bear in mind, however, that swans, albatross, vultures and turkeys also have aerobic power outputs of around 4.5 N/kg from their flight muscles, and they can fly just fine. The secret to their takeoff lies in the great power of anaerobic muscle contraction, which provides twice the power achieved under aerobic regimes. Using anaerobic power, giant azhdarchid power outputs are 10.098 N/kg of body weight, a value surpassing the 9.8 N/kg and matching the anaerobic power outputs of a 10 kg swan or 1 kg vulture (see graph, below). In terms of power availability, then, giant azhdarchids would not have struggled to launch any more than a large bird, so all these suggestions about poor takeoff ability and whatnot can be put to bed.

The awesomopower of giant pterosaur flight

Although azhdarchids are frequently discussed for their natty terrestrial capability nowadays, it's important to remember than any substantial travelling they had to do was probably performed in the air. Computations of the flight abilities of giant azhdarchids have returned seriously impressive results (Witton and Habib 2010). As mentioned above, azhdarchids likely employed anaerobic power for strenuous flight activities like takeoff and perhaps flapping bursts, and likely relied mostly on thermal soaring and flap-gliding like modern raptors to remain airborne for long periods. Their minimum sink and best glide speeds are steady cruises at 16.3 - 24.9 m/s (58.7 - 89.4 kph) but, if they were in a hurry (such as looking for a source of uplift), speeds of up to 48.3m/s (173 kph) were possible for short durations. We estimated that azhdarchids had about 90 - 120 seconds of anaerobic burst power before tiring, meaning these animals could go from a standing start to - literally - several kilometres away in the space of a few minutes. Yowsers. What's more, the size and bodily resources available to such large creatures permitted tremendous flight times: up to 16,000 km of travelling without resting or foraging were likely possible. That's the equivalent of an animal flying from London to Vegas non-stop, realising it forgot its passport, and then flying home again without touching the ground.