Gryphons are a staple fantasy creature. But for my world I prefer creatures to have some grounding in realism.

Is it possible for a bird to evolve into an effective Gryphon? Increasing number of limbs seems to be hard to justify, but I'd be curious to know if it's possible.

The main properties are: Powerful talons 4 limbs that can be used to walk, the front limbs should be able to grasp and be used offensively. Feline style predator, high agility, strong muscles and able to withstand some punishment. At least lion sized.

Not necessary, but nice to have: Ability to fly/glide Ability to be ridden Ability to fly with a creature in it's talons. Potential for domestication. Inverted wings if used as ambulatory limbs.

Atmospheric pressure is currently earth-like, but can be increased if it's the limiting factor.


9 Answers 9


An anatomically correct griffin would be descended from a theropod ancestor. Some theropods had both four limbs and wings. In other words, they already have the right number of limbs for a griffin.

Their build – arms with wings – makes them the closest match for the classical griffin.

A griffin descended from a theropod ancestor could have wings attached to the front legs.

I am thinking of Deinonychus.

Deinonychus was 1.8 meters tall. This size would make it a good starting point for a griffin.

Studies of juvenile Deinonychus skeletons have revealed mobile shoulder joints, evidencing flight of some sort.

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  • $\begingroup$ "Some theropods had both four limbs and wings." What? Example? $\endgroup$
    – addaon
    May 8 at 15:50
  • $\begingroup$ Deinonychus is a theropod with both four limbs and wings. $\endgroup$ May 8 at 23:01
  • $\begingroup$ Sure, but a chicken is a bird with four limbs and wings. For both a chicken and Deinonychus, the front limbs act as wings. $\endgroup$
    – addaon
    May 9 at 3:08
  • 1
    $\begingroup$ There is a significant difference between having wings and having wings with dexterity resembling that of legs. Plus Deinonychus is an agile predator, which makes it much more "catlike" Thus much more able to evolve into something like a Griffin. $\endgroup$
    – Spoon
    May 9 at 13:05

While most other answers focussed on the evolution process I want to tackle the creature as you want it be in the end.

Probably no.

The ones I mostly think are unrealisitc is:

able to withstand some punishment
ability to be ridden

Birds (and other airborn creatures) can mostly fly because they are exceptionally light for their size. And the heaviest parts of most creatures are: muscle and bones.
Almost all birds have hollow bones for that exact reason, to save weight to be able to fly.
But hollow bones are also pretty weak and can break much easier than full bones. Also adding a considerable amount of additional weight on the back of the creature in form of a rider sounds unrealistic.

Remember, just scaling up smaller birds in size and giving them extra limbs doesn't work. If you double a bird in size, you also doubles the lift it can produce, but you quadruples the weight.
While you can alleviate some of that by increasing the atmospheric pressure, you won't be able to explain such a big and heavy flying creature with that and still have humans around.

A flying creature big as a lion is already a stretch. Strength to carry 50-100kg more on the back and not having hollow fragile bones is just unrealistic.

However, don't let it stop you. You are writing fantasy, you are not constraint by reality. Do not let realism stop you from imagining and describing wonderous creatures in a fantastic world.


Increasing number of limbs seems to be hard to justify, but I'd be curious to know if it's possible.

People are born with with extra fingers, extra heads, extra arms or extra legs... same thing happens to animals.

Meet the 14-strong De Silva family who were all born with six fingers and six toes on Body Bizarre

Do people find women with bigger tits more attractive even tho bigger tits don't produce more milk, they are cumbersome, cause back pain and are a waste of energy, as well as a direct relation of more tissue = more cells that can turn into cancer....so having a bigger breast is always a factor in having a lower quality of life and lesser quantity of life in a vacuum.

The answer is yes, that's why humans were selected to have bigger boobs than most mammals.

So ask yourself this, is there any possible use any animal could have from an extra limb that would make it more likely to reproduce or more likely to fit into a new niche? if the answer is yes, then it will deviate into a new sub-species... and then a speicies and then eventually an entire genus or an entire family.

If there's no way for you to explain how something could benefit your animal... just degress to sexual selection....we humans are sexually selective for a lot of useless stuff, so are most animals ever to some degree at least.

And if someone says "but sexual selection only works for one of the two genders".....well then your answer shall be "not in this case" cause exceptions always exist.

and if you don't care about the sexual selection thing and still can't find any use for your animal... then just delete an existing animal, make it go extinct so that your new creatue may replace it.... like how in real life birds have replaced the biological role of rats and reptiles in some isles, basically becoming useless ground-dwelling flightless birds with smaller brains that eat trash... the opposite can happen too.... like how some birds evolved to repace big carnivours dinosaurs...

  • 2
    $\begingroup$ To be fair, in the title of the article you link, "De Silva" family isn't really a good way to name a family, since more than 10% of the entire population of Brazil bears that surname (including me and the current president), and those people aren't related. "Silva" is just a generic placeholder surname like "Smith" is in the USA, but used by a much larger population percentage. Further, "de", "da", "do", "dos" and "das" means just "of", thus those aren't considered as part of the surname, they are just a syntatic element with very little to no real value, so the surname is just "Silva". $\endgroup$ Jan 13 at 3:37
  • 2
    $\begingroup$ Extra fingers or toes can be a heritable trait, but I've never heard of anyone having a heritable condition that results in extra limbs, let alone head. That kind of mutations are too severe to survive with. (People are sometimes born with that kind of features, but they are not a result of germline mutations and therefore not heritable.) Birds, being vertebrates, also have quite poor tolerance to mutations that drastically alter the body plan. $\endgroup$
    – Cloudberry
    Jan 15 at 19:11
  • $\begingroup$ @Cloudberry Everyone has muscular-skeletal mutations, some people have more than 2 biceps... and the percentage of those people is quite hight, some people have completely different muscular structures or extra bones or missing bones or missing tendons or extra nerves and so on... so like if people can often have 4 biceps in one limb instead of 2 and live their life normally without ever noticing until a doctor scans them... how much extra evolutionary work is to just straight up having 1 extra humerus bone? 1 extra bone vs 2 extra muscles.... the 2 extra muscles is clearly more difference... $\endgroup$
    – Xenophile
    Jan 15 at 20:41
  • $\begingroup$ @Cloudberry to continue, people can be born with up to 7(or possibly more) extra clone muscles and never notice, it's common, it's hereditary... this with extra completely separated tendons... you might actually have 14 bicep muscles...7 in each arm, with 7 tendons each and you might never notice. $\endgroup$
    – Xenophile
    Jan 15 at 20:47
  • $\begingroup$ @Blue If you don't even notice, then the function of your limbs hasn't changed that much. It's very different from having an extra pair of functional limbs, which is never seen as a heritable condition in mammals or birds. $\endgroup$
    – Cloudberry
    Jan 16 at 17:43

Despite me doubting body conformation of traditional griffon would be any aerodynamically efficient, I believe an extra set of limbs would inevitably require extra vertebrae and shoulders to fit , as well as novel brain functions to coordinate them.

Duplication of body segments is something happens naturally sometimes by mutations and not always lethal, but it is almost impossible to have a complete duplication of limbs with all the correct muscular, skeletal and neural structures together. For body plans there are conserved genes like Homeobox genes that prevents such glitch from happening.

So, unless an animal is super lucky to have this duplication mutation that successfully functions, plus it doesn’t upsets other parts of the body e.g. the guts, plus this trait brings fitness of some sort which may help it win social and sexual selection, plus its offsprings turn out viable and fertile… would this lucky creature gain the tiniest chance of being the ancestor of a new species.

Other things to consider: background mutation rate of ur world, niche that the creature may fill into, also perhaps rethink about the ancestor of ur new hexapods, 6-limbed descendants of lobed-fin fish may be easier start points than birds.

It’s my first time using this forum and hope my answer helps!


I would start with an owl.

Owls are already cat-like ambush predators. The only thing that differs them from felines is that they glide down on their prey rather than pouncing on it.

Largest owl to ever existed was the giant Cuban Owl, at 1,1meter tall. It was flightless, but not too heavy to be able to glide if evolution took it a different way.

There is no reason why a species of owl could not evolve to be able to crawl around and climb like a bat or a pterosaur, using claws on its wings to walk on, but also use the same wings to flight or glide short distances.

My assumption is that a "Crawling Owl" or "Lion Owl" about 70kg in mass, 2meter long, and with about 4meter wingspan could be effective ambush predatory that could climb up on trees and cliffs, and glide down to take down big prey.

It would be too heavy to fly longer distances, but also durable enough to maul prey the same way a cougar does. In fact, its mass could be a feature not a bug: it would hit with a much greater force gliding down. An owl can fly with the speed of about 50kmh, if that owl weighted 70ish kg, it would hit its prey like a wrecking ball.

Owls are fierce, intelligent, and very, very stealthy. A cougar sized owl would make a surprisingly good predator. Not sure if it would be easily domesticated, as owls tend to be ornery a-holes, but selective breeding and a lot of time could maybe change that. In theory, the Crawling Owl could be ridden by a lightweight person, though I imagine it would not be very effective, as the mount would be slower than a human just jogging.

I actually found a picture of something like this:



I will admit, I am not an evolutionary biologist, and I don't know that much about how the specifics of traits given to creatures go as far as naturally selection. But I will tell you this: birds are descended from dinosaurs, and many species of dinosaurs had four legs. Plus, there were such thing as winged/feather dinosaurs. Sounds like all the genes you need already exist.

All you need to do is say that, at some point while dinosaurs were alive, by cross-breeding or natural selection, gryphons started out as a kind of dinosaur with four legs and wings.

After that point, you can say that (like modern birds) the gryphon species evolved to have fur and feathers, differentiating it from the rest of the dinosaur population.

Oh, wait, dinosaurs had that to begin with. So

In that case, it seems like you're actually all set. There are so many different species of dinosaur already, I'm sure it wouldn't be too much of a stretch to add one that survived extinction as a gryphon-like creature, wouldn't it?


Naturally, no.

In history the biggest birds that still could fly were the Haast's eagles with a wingspan of 3m, and still those flying giants only weighted 15Kg and couldn't carry much. If we go farther back we have Quetzalcoatlus, the largest flying animal, with a wingspan of 15m and a estimated weight of 70Kg.

So, having the size of a lion is no problem. And in the case of Haast's eagle it had 6cm claws and was a powerful predator.

So, what you need to create this gryphon-like animal is a similar environment to the one that created the Haast's eagle: Isolated island with a lack of land predators that would have allowed birds to fill the niche.

So now you have a large bird apex predator, it flies and could have developed some feline-like characteristics via convergent evolution. Locals could have learned to tame it to send small packages and messages across the islands.

But, to go further we will need to play around with some more magical elements.

Flying is hard, it requires an animal to specialize, reshape it's whole body and metabolism for this single task... But, what if it wasn't?

Let's say we introduce cavorite in this bird's diet, the mineral could be naturally occurring in higher altitudes and end up accumulating in the bones. Now these birds get some form of naturally occurring anti-gravitational abilities that make flying so much easier!

Without the constraints of weight they can grow and develop muscles that are used for more than just flying. Now they can grow big enough to carry riders and to prey on animals the size of elephants.

The last burden to overcome are the six-limbs, unless you want to make those gryphons actually some weird form of insect, they would need to develop some really lucky mutation that would give them an extra pair of limbs.


First Problem; You'd have to posit an ancestral hexa-pedal life form, probably an entire evolutionary clade of 6 limbed animals (probably aboreal) that co-existed with quadrupedal species. Something like micro raptor a (bird like) small dinosaur with 4 wings. See link. Four Winged flying dinosaur unearthed in China Only in this case your animal has 6 wings well at least pseudo wings. Sort of doable (at a push I guess).

Second Problem; the animal has to be a predator that starts out small and then grows bigger (perhaps as the its forest enlivenment changes over time into open woodland and fields). This means that 2 pairs of limbs adjust to more time spent running on the ground and lose their fight capabilities but there are still enough large dangerous predators around that make being able to fly (badly) with two wings helping it escape death by returning to the trees. It could be the first pair of limbs that stay 'winged' or the middle pair'. Again sort of doable, I suppose.

Third problem; There's a some kind of die off events that kills off many species of large ground dwelling predators and opens up new niches. Some of your flying hexapods take advantage of this and return to the ground becoming the new dominant land predators, growing in size as they do. But your boy for whatever reason still faces a strong evolutionary pressure to retain flight while also growing larger. Why??? Maybe they're were Johnny come lately's when it came to leaving the trees. Who knows? Maybe they evolved in large rift valley or canyon systems, maybe mountainous terrain? In any case its an environment where cliff faces/rock walls and mesas etc make good nest sites and observation points for prey. Probably not very likely but lets go with it anyway.

Fourth problem; Now they're large(er) but they won't be able withstand punishment. Why? A male lion can weigh up to almost 200 kilos and tackles large, dangerous prey. It has to be tough but it also doesn't have to fly. That means it can afford to evolve the dense bones and heavy musculature i.e. the very stuff that makes it 'tough'.

Your Gryphon on the other hand has to be able to fly. Which brings us the largest flying animals ever to known to have existed the Quetzalcoatlus. They are believed to have reached a max weight of about 250 kilos and to have had a wingspan of about 10 meters. See link: Quetzalcoatlus

The big Problem? They could only achieve flight at the cost of having very thin (hollow) bones and a muscular system maximized for supporting lift off and landings with most of its flight profile being gliding. They were simply not adapted for tackling/bringing down large prey without suffering crippling injuries as a result and actually appear to have fed on small animals or fish that they stalked like herons and egrets etc do today.

This is killer problem I can't see a solution for. In an Earth like environment? You can have 'large and tough' like a lion (but can't fly) or be large and able to fly like a Quetzalcoatlus (but then you can't be 'tough') There's no way to be both.


https://en.wikipedia.org/wiki/Roc_(mythology) The bird Roc in arabian mythology is based upon a case of island gigantism in birds https://en.wikipedia.org/wiki/Elephant_bird on madagascar if i recall correctly. And we can ride its nearest neighbor https://en.wikipedia.org/wiki/Struthionidae

Now to go back from walking bird to gliding to flying needs survivable incentives. And enormous wingspan.


So our Bird weighs: 140 kg - the passenger weighs 90 kg gives us 230 kg gives us a wing area of 50 square meters to get into glider ratio. That is some serious handicap as a wing. Assuming a 3 Wings on each side configuration, that is 8 square meters per winglet. And now we need energy and muscles to move it. Which need additional wings - or energy to lift it. And we see where this is going, birds are living under the tyranny of the: https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation to be able to flight. Which is why most of them are small and the bigger ones are all depending on prey (autonomous food collection robots aka birds) to sustain them.

So your bird also needs a prey infrastructure to keep its rocket in the air.


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