What could cause an avian species to become intelligent?

Question

There have been a few questions about an intelligent avian species lately and they have gotten me thinking.

It seems to me that it would be hard for an avian species to evolve to be more intelligent past a certain point. The main problem being that I can't imagine the immediate benefits of being more intelligent would outweigh the drawbacks of being heavier because of it (at least on a planet similar to earth).

One thing that does speak in favor of intelligent bird is that they have appendages which are not often used for moving around (in the air) available. Being able to use those more creatively might pose a large advantage. Sadly I can't imagine those appendages being positioned in a way that makes them useful for intricate manipulation of the environment. (don't dwell too much on appendages in your answer, there are plenty of reasons a species could become intelligent)

So the question is: What would cause (or could explain) an avian species to naturally become more and more intelligent to the point of sapience and beyond (and remain largely airborne)?

This question assumes a planet similar (but not necessarily identical) to Earth.

Answer 1

The factors that naturally selected humans (or more to the point, earlier primates/hominids) for increasing intelligence are somewhat speculative, but I think any of the following is plausible enough for world-building. Or any combination consecutively or concurrently:

• tool use
• complex communication
• maintaining large numbers of individual relationships in growing social groups, that is to say "mentally modelling" lots of other individuals
• as a special case, deception within stable groups, and counter-measures to deception

An avian has two gripping appendages fewer than a primate[*] (or just one fewer if you count the beak, which is probably better for tool use than a primate mouth). No bird I know of, even flightless, has re-evolved gripping forelimbs, and the feet probably aren't well positioned/articulated for throwing, so the tool-use benefit is less than for humans, but still there. Indeed, some avians use some tools. The social advantages could still exist in the right circumstances.

So like you say, you'd need to make the case that doing these things justifies carrying a brain around with you. An adult human brain weighs approx 1.3kg, there are extinct hominids down below 1kg that were probably pretty smart. I suspect that even the largest pelicans' bills are considerably lighter than that, but I can't find a figure. I think one can very safely assume that whatever a pelican carries as beak-weight, a sufficiently motivated bird could carry as brains given the right evolutionary pressures, but multiplying that by 4 or 5 is hardly a slam-dunk.

So I think your instinct is correct, it's difficult to justify, but I think you could get there. They're never going to be able to carry all that much in flight, but since an eagle can carry off a young lamb, a large bird in principle could at least get off the ground with a human-sized brain [**]. So it depends how much you're willing to sweep under the carpet of "they benefit from evolving an increasingly complex society", and how much you're willing to give way on how big a brain they really need to be "sufficiently" intelligent for your purposes. Are you willing to posit that they have more efficient brains than humans somehow? If so then just get on with it: intelligent flying birds.

Avians actually have one physical advantage over primates when it comes to brain capacity, which is that humans exist at the limit of the infant skull passing the pelvis while still being just sufficiently developed to survive. Birds have a whole egg-laying setup arranged already -- don't ask me how it works, but it does.

[*] - to be fair, humans turned out to only need two gripping appendages to satisfy our tool-use needs. But then we're standing on the two we decided didn't need to grip, birds don't have that luxury. Unless they can figure out a way to stand on their wings, which seems awkward.

[**] Or supposing two swallows carried it together? They'd have to have it on a line.

Answer 2

Intelligence doesn't require opposable thumbs. Civilization does require multiple species.

When thinking about animal intelligence, it’s hard to keep our biases out of it. There’s a tendency to apply the human evolutionary story living in many of the answers to this question. That’s not unreasonable. Humanity seems like the most intelligent species and the only material culture we know of. Some evidence beats no evidence.

Many of the answers I’ve read for this question either assume alien races must be primate analogs or that flying creatures can’t become overly intelligent.

I think it’s pretty obvious you are looking for an flying alien race for a story that is comparable to humans or a civilization that is comparable to ours. Before I address these possibilities, let me dive into human evolution to look at the evolution of intelligence.

I often hear confusion about human evolution. “Post hoc ergo proctor hoc” is Latin for “after this therefor because of this.” It represents the common logical fallacy that sequence alone proves causality. In this case, that because reasoning intelligence is necessary to produce civilization, tool use must be in place to allow the development of higher intelligence. Or that civilization requires a reasoning intelligence because humanity had it before we civilized. My only point here is this, apes evolved a high order of intelligence for reasons that had little to do with the ultimate utility of having intelligence — such as civilization. So there’s really two questions here.

1. Why did a few animal species evolve a high order of intelligence?
2. How did civilization evolve for homo sapiens?

First, there are many intelligent animals with new research revealing more all the time — pigs, octopuses, bears, parrots, etc. But there’s general agreement that the big three are the great apes (which includes humanity), elephants (several species past and present), and dolphins (including killer whales).

Looking at these three animal groups, it’s difficult to find common patterns. Dolphins are predators; elephants are herbivores, and apes are either herbivores or omnivores. Elephants and dolphins don’t really use tools and dolphins clearly lack any kind of manipulative appendage. One group is semi-arboreal, the other land based, and the third aquatic. Non-human apes are polygamous, elephants matriarchal, and human relationships are too varied to easily pin down — dolphins too actually. And only humans have forward facing eyes.

The commonalities that do exist are the possession of a large, complex brain, a high metabolism, a long life span, and extremely complex social structures - not to be confused with merely being a social species. In fact, social species are among the most stupid animals; consider the social insects.

Humans, chimpanzees, and dolphins in particular posses what are called fission/fusion relationships. This means treating other individuals alternately as friend or foe depending on both the immediate and long term advantage. Social species treat each other consistently as friends. Individualistic animals compete with each other openly, almost as opposing species. But only apes and dolphins could ever indulge the axiom of, “the enemy of my enemy is my friend” or “politics makes strange bed fellows.”

It seems the evolution of politics drives the development of higher reasoning intelligence. Why? Because it requires not just self awareness, but the ability to predict the behavior of other individuals, to walk in their shoes, so that you can deceive them.

A chimpanzee in a zoo, given a banana, won’t simply hide the banana to avoid sharing it, it will alter its behavior to appear as if it doesn’t have a banana when other chimps are looking. This requires the chimp to calculate how its behavior appears to other chimpanzees. It is a lot more cognitively challenging to lie effectively than use a tool.

What’s germane to the possibility of intelligent birds is this. While I don’t believe science yet has a handle on exactly why a few species have evolved politics, all that appears required is a large brain, a long life of experiences, and some reasonably sophisticated means of communication. By that measure, almost any animal type imaginable could conceivable evolve reasoning intelligence.

As for the development of civilization, it might be worthwhile to consider what a long shot that was all by itself. Homo Sapiens existed for almost 100,000 years before they developed beyond stone age tribes. Considering too that since we now know Homo Sapiens successfully interbred with Neanderthals (I’m 1.7% myself) we must consider them more or less the same species. Thus human intelligence existed on Earth for hundreds of thousands of years without civilization appearing. It was only after the end of the last ice age, that conditions in a few places put our ancestors next to a few useful species of plants and animals thus making agriculture possible.

Agriculture and animal husbandry both are not inventions in the modern sense, but rather symbiotic relationships - another evolutionary process. Local conditions must be sufficiently variable to drive an evolutionary solution to stabilize the variability — to the mutual advantage of two species (humans and wheat for example), but not so difficult (ice age tundra) that an early evolutionary experiment at cooperation couldn’t possible succeed.

Simply put, civilization doesn’t belong to humanity alone, but also to wheat, rice, corn, dogs, goats, chickens, and cattle. If all these species hadn’t evolved together, all humans would still be living in caves — no matter how clever and devious we are.

Thus if you’re looking for your avian species to have material civilization, broaden your thinking out to the planet they live on and the other species they partner with. What geological or climate forces caused the symbiotic coevolution of civilization with one intelligent, political species (the birds) in the drivers seat, but others equally important?

P.S. Nobody mentioned parrots. They’re intelligent, arboreal, long lived, have opposing digits, and are great at communication.

Answer 3

As you've suggested intelligence is subject to natural selection just like any other attribute. A bird could be the smartest bird in the skies but unless it survives and reproduces that intelligence will never be passed on to the next generation and spread through the species.

So what makes an intelligent bird more likely to survive/reproduce than an ordinarily intelligent bird?

• The ability to anticipate dangers/opportunities
• The ability to work as a team to increase chances of success
• The ability to use tools (suddenly being the strongest doesn't count for as much)

An increase of any of these could give a creature a marked advantage (after all puny little humans survived).

Wings as you've pointed out are not particularly dexterous, intelligence (in it's early stages) go hand in hand (sorry) with the ability to use tools/implements. However don't forget many birds do use tools!

Therefore the suggestion is that either the creature would evolve dexterous limbs (such as hands AND wings) or their tools would become more and more dependent on limbs they do have (beaks and feet/claws).

Weight is obviously going to be an issue however a human brain only accounts for 1:40th of a human's weight! However small birds are more like 1:14... this suggests that your bird will need to increase in size as well as intelligence.

All in all the odds are stacked against them, having said that. There have been some truly enormous flying creatures in the past!

Answer 4

Given that there are already intelligent birds (parrots, ravens, magpies) with intellectual abilities akin to a human child, this suggests that their brains are far better optimized than human brains, weight for weight. So an avian brain of equivalent intellect to a human adult would not necessarily have to weigh anywhere near 1.3 kg.

Some research on the subject:

1. Abstract rule neurons in the endbrain support intelligent behaviour in corvid songbirds [Nature]

Despite the lack of a layered neocortex and fundamental differences in endbrain organization in birds compared with mammals, intelligent species evolved from both vertebrate classes. Among birds, corvids show exceptional cognitive flexibility [...]

2. On the Sydney Morning Herald

Crows may be as intelligent as apes, scientists say

3. Bird Intelligence [Wikipedia]

Birds in the crow family (corvids), and parrots (psittacines) have been shown to live socially, have long developmental periods, and possess large forebrains, and these may be expected to allow for greater cognitive abilities

4. Smarter than a first-grader? Crows can perform as well as 7- to 10-year-olds on cause-and-effect water displacement tasks [Science Daily]

"When we gave them only four objects, they could succeed only in one tube -- the narrower one, because the water level would never get high enough in the wider tube; they were dropping all or most of the objects into the functional tube and getting the food reward," Logan explained. "It wasn't just that they preferred this tube, they appeared to know it was more functional."

5. Corina J. Logan, Sarah A. Jelbert, Alexis J. Breen, Russell D. Gray, Alex H. Taylor. Modifications to the Aesop's Fable Paradigm Change New Caledonian Crow Performances. PLoS ONE, 2014; 9 (7): e103049 DOI: 10.1371/journal.pone.0103049 [Link]

The Aesop's Fable paradigm requires an animal to drop stones into a water-filled tube to bring a floating food reward within reach. Rook, Eurasian jay, and New Caledonian crow performances are similar to those of children under seven years of age when solving this task.

6. Crows wield tools with human-like skill [NewsScientist]

7. Current Biology vol 17, p 1 (DOI: 10.1016/j.cub.2007.07.057)

8. Brains and Beauty: African Grey Parrots [African Greys]

9. Parrot Learning [Science Net Links]

10. The Alex Studies - Cognitive and Communicative Abilities of Grey Parrots [NY Times]

11. Evolution of the avian brain and intelligence [Cell]

12. Cognitive ornithology: the evolution of avian intelligence [Phylo. Trans. B]

Answer 5

I'll give this a try...

—one thing I'm having issues with is maintaining flight. If you take a gorilla and compare it to a human, you'll find the Gorilla is, pound for pound, significantly stronger than its human counterpart. As great as intelligence is, the temporal brain significantly reduces a creatures physical abilities, both by consuming a huge amount of the bodies resources and by forcing thought (quelling the much quicker instinctive reaction in favour of thought). If the same ratio of the degradation of physical abilities from Gorilla to Human would exist for an intelligent bird, I'm not so sure it would be capable of flying.

For intelligence to rise, you need evolutionary forces to favor intelligence. In the case of Humans, shared defense is one of those initial driving factors. Not only was it good to be intelligent to spot dangers for yourself, but it became pivotal for you to be surrounded by others that could also spot and process these dangers (your intelligence in picking out a bird of prey and acting on it = my survival). So, although individual intelligence was helpful, group intelligence defined the species ability to survive.

To me, this see's most birds of prey drop out of the intelligence race...as smart as a single bird can get, there is no evolutionary pressure for them to surround themselves by like intelligence...in fact, through competition, it's more advantageous to quell the other like intelligence creatures before they do the same to you.

This might sound odd...but I give the highest chance of intelligence evolving to the now extinct Dodo where their group existence and dependence on one another is the pressure for the entire group to become more intelligent (stupidly enough, this may be why they went extinct so quickly...if you shot a Dodo, hundreds of other Dodo's would run up to see what happened).

Unfortunately, this is back to being unable to reconcile the parameters of this question and their inability to fly. Would be really interesting if the possibility of a flightless bird evolving intelligence and then once again evolving the ability to fly through their intelligence.

Answer 6

Crows happen to be intelligent enough to buy food from a vending machine using coins. Crows aren't even that big.

Pigeons beat mathematicians at the Monty Hall Dilemma.

That seems to be enough intelligence to learn that you can kill prey by carrying stones and dropping those stones from a height on prey. Targeting the stone so that they hit will be improved by intelligence. Intelligence also allows for a selection of better stones to drop.

Over time that means you have a selection bias for higher intelligence.

Answer 7

Given what intelligence relatively (to humans) small-brained creatures like magpies and keas have at their disposal, I think it's just a matter of the right environmental and ecological conditions occurring. A world rich in energy with lots of high places would help, especially if the gravity were a little lower than Earth's, or the atmosphere a little thicker.

Consider what real birds already do: European magpies appear to be able to recognize their own reflections, and can use a mirror to find colored tags stuck to their throats and remove them with their feet. Crows recognize the regional accents of other crows and adjust their calls to match. Numerous species of birds employ tools toward various ends.

Other corvids possess sufficient intelligence to goof off, such as by depriving humans of the status of "only species known to enjoy snowboarding":

https://www.youtube.com/watch?v=3dWw9GLcOeA

Starlings may even have been demonstrated to have some grasp of recursive syntax:

http://acp.eugraph.com/news/news06/gentner.html

They may well be able to achieve the same intelligence as primate brains larger than theirs--there is, after all, a strong evolutionary incentive for birds to get as much thinking done with a given mass of brain. Moreover, their brains have a rather different physical architecture (although if you're designing a fictional species I guess you can put whatever you want there--hey, maybe even put some really nice integrated circuits in there if you're willing to get weird.)

A chickadee needs to remember all the dumb little places it hid seeds, and a crow is more likely to make it through the winter if it remembers lots of places where people leave sandwich fragments. Also, a large vocabulary of calls gives a flock a better ability to adapt to unexpected situations, and a songbird migrating into an area where the calls are a little different is more likely to find a mate there if it learns the local "accent".

Which actually does happen. I'd post a link, but the red box to the right says I "need at least 10 reputation to post more than 2 links." Fine, encourage me not to cite sources then. This place must adore hearsay. While I'm at it, there's even some evidence that crows are capable of deception. There's a great article on New Scientist that I can't link to.

Anyway. Point here is some avians are already not that far from being what we might consider intelligent, so you've got something to work with already.

Physics is unkind to things that fly, but not so unkind as you'd expect. We already have a good idea of the upper limit of size for animals capable of powered flight on Earth.

Consider the Argentine teratorn (Argentavis magnificens). They were enormous! Weighed as much as some humans, and was pretty much a really huge buzzard. Smaller relative species were just terrifyingly large birds of prey. So you have a lot to work with: You get up to seventy or eighty kilograms if you accept that you might need a wingspan of seven meters. So, assuming Earth gravity, your hypothetical sapient bird should preferably weigh less than that. Let's no go too close to the limit; let's not use up all our wing loading so easily. It's bad for agility.

If I think about this like an engineer, it's not hard for me to imagine making magpie or a kea bigger until it can power a pretty nice brain. Maybe even one on par with that of a human. As long as it weighs less than a teratorn, you can probably get that to fly. Nature is going to give you more leeway here than you expect. It's easy to scoff but it's not that hard to design something that works.

The challenge to the worldbuilder is to imagine what kind of world would favor such an evolutionary outcome. I sometimes imagine a planet with slightly less-than-Earth gravity and lots of small volcanic islands*. Some really good reason to fly, remember things, and organize socially, and the right environment to support the energy demands this entails, and perhaps to present a mixture of risks and rewards that favors intelligence.

As for tool use, besides the fact that they already do it, birds have some options. For one, their balance is excellent and their beaks and feet are really dexterous. The feet are opposable, and the beak is innervated--capable of feeling things--and highly maneuverable due to the large number of cervical vertebrae even very large birds possess. That's already a lot to work with. Besides that, why can't the wings have a few opposable claws? Pterosaurs and juvenile hoatzins both have wing-claws, and there's no reason those couldn't evolve to be more articulate given the right environmental and ecological incentives. It wouldn't be any weirder or less plausible than triosseal canals or having four or five color channels in your vision.

Never forget incentives, and never forget selection strategies, which are even more ridiculous. Consider birds of paradise. Yes, there are reasons for them to exist, and they're absurd. That animal is nature smirking and saying "Because I can. Because it's not impossible and because I can." If it's biophysically possible, you can probably come up with a reasonable, plausible way for it to evolve.

If it's lighter than an Argentine teratorn and no more ridiculous than a mantis shrimp, it can probably exist. I think making a magpie big enough to do calculus under the right environmental conditons is really not all that hard to imagine, all things considered.

*Maybe a habitable Jovian moon, if you want to risk arguments with physicists about whether you can reach a compromise between the risk of solar wind stripping the atmosphere due to insufficient proximity to the parent planet's magnetic field and the loss of too much water and gas from the moon due to reflected and radiated heat from the parent planet. Maybe it's a red dwarf or something. Maybe I just can't get over how cool it sounds and am too optimistic about the feasibility of something ridiculous.

Answer 8

Consider an evolutionary hazard gaming strategy.

As seen from the average mammal, the human brain is completely oversized and costs ridiculous amounts of energy just to operate in idle mode. No proto-intelligent social life form that occupies a sweet spot such as chimps or ravens can reasonably favour such a development.

Imagine that proto-humans were expelled from such a sweet jungle spot out into the dry savannah where they had to steal a living from an established predator / prey scheme. The predators were mostly night hunters and would, like their prey, rest at noon, hence both would never evolve the ability to hunt or run away in the heat of high noon. The proto-humans would lose most of their pelt, evolve water cooling through sweat and hunt the prey to thermal shock. However, since hunting at the borders of overheating costs a lot of brain cells, they would evolve large amounts of backup. From there on, as the cooling efficiency increases, the backup suffers less thermal loss and gets used to enhance socializing and toolmaking, which in turn increases efficiency. Finally, by this cascade, intelligence emerges as an unintentional byproduct.

Construct a similar catastrophic exodus and drop your avians into a niche that lets them bet their survival on thermal imbalance or any hazardous corner case that leads to accidental accumulation of otherwise ruinously oversized brain capacity.

Answer 9

What exactly do you mean by intelligence? Is reasoning and problem solving enough or are we looking for avians that will eventually develop space flight or derive the Standard Model? A number of experiments on ravens show them to be quite capable of the former, whilst the latter will almost certainly never happen without the ability to manipulate sophisticated tools (imagine building a particle accelerator with nothing more than beak!).

However, I would argue that it's an exacting critic indeed who wouldn't recognise reading, 'riting and 'rithmetic as signs of intelligence. I see no obvious barrier to raven's developing beak-graffiti to accompany their spoken (tweeted?) language. This is something that could easily occur spontaneously without much (or even any) physical evolution. As far as we can tell human writing only began around 10-30,000 years ago, whilst we have been largely physiologically unchanged since the rise of Anatomically Modern Human about 200,000 years ago. That is to say, we didn't just develop writing when we became smart enough to understand it - it seems to have arisen spontaneously, seemed useful, and stuck around. Human writing began with simple counting systems, and it is easy to conceive the utility of such a system even to ravens. A savvy raven could mark days to decouple themselves from the environmental cues of changing season and get the jump of the competition when migrating.*

An animal with a spoken/squawked language and in the habit of making marks will eventually come to use them for more than numerals. High points might be marked with a "tag" to warn off rivals, strings of landmarks might be marked as sign-posts home, allowing the raven to venture further to find food or mate. Reminders can be left of caches of hidden food. None of this writing needs to be any more complex than their already demonstrated prruk-prruked language skills in order to be useful. Eventually the landscape will be dotted with raven writings, and certain pieces of information will pass from one generation to the next - summer last this many days here, this woodland is good for mice, etc.

If another species got this far, I wouldn't hesitate to consider them intelligent. There doesn't seem to be any reason at all why a raven couldn't do any of this without any further evolution, and we should not be discouraged by the fact that they haven't done so already - modern humans lazed about for 170,000 years without doing it. But what is exciting is what comes next - what might be possible with a little more evolution.

Sign-posts to hidden food might be read by other ravens, encouraging the use of misleading marks and an encryption/decryption arms- (wings-?) race. A migrating bird might add another 30 day-marks to his calendar before leaving, so that next years rivals postpone their own migration. When a technology proves useful then in time it typically becomes essential - if farming can support a larger population, then in time there will be a population that can only be supported by farming, etc. In this way literacy will eventually become an essential skill among ravens, as the underfed, exhausted illiterates are passed over by potential mates attracted to the new breed of well-fed, glossy-feathered renaissance ravens. And one day, they will be calculating their latitude and performing spherical trigonometry to plan their migrations...

(* yes, I know most ravens don't migrate, but some do, and this is world-building so I can have ravens migrate if I want. Ravens are the birds most commonly associated with intelligence, and migration seems a behaviour in which intelligence might be advantageous.)

Answer 10

The error is in the title. Nothing would cause an avian species to become more intelligent. As stated above (Liath), only if there is a survival advantage for a group of such a species being somewhat more intelligent, then those traits would be passed on. A continuing process of natural selection could then select for those individual having the advantage of greater intelligence. However, such selection does not necessarily have to occur, and even if such a process were available, the animals might not have any significantly increased intelligence. They might get through by dumb luck. Nothing can cause the trait of higher intelligence to occur; if it occurs by chance then there is the possibility it can be passed on to subsequent generations. It is a great mistake to assume Evolution required humans to evolve from primates, and that Evolution will produce some other advanced human to replace us.

As an aside, we had a chance to develop higher intelligence, because our ancestors ate a high fat diet after beginning to use stone tools. I wouldn't be surprised children are suffering because we are incorrectly feeding them low fat foods. Brains require large amounts of cholesterol to develop.

Answer 11

Time, and absence of humans? Corvids (jays, crows, ravens) are pretty intelligent in somewhat human-like ways, including interest in object manipulation, large-scale social and cooperative behavior (especially crows), aggressive territoriality and mutual defense, and language (especially ravens). Get humans out of the spotlight and give them time (100,000 years?) and circumstances, and perhaps evolution of stronger ability to work with objects (more claw strength and manipulation ability).

On the other hand, I think this comes with the assumption that the path humans have taken is likely and has universal values. Our outlook on our own evolution, cultural assumptions, and our view of other species, has a huge amount of self-justification and denial in it, it seems to me. I wouldn't expect every intelligent species to end up with the same traits that human civilizations have arrived at.

Answer 12

Let me add another point of view. Most answers assume that the large brain evolved in order to gain intelligence. However, I've once read another hypothesis (unfortunately I don't remember where): The human brain originally grew big because humans were in an environment where the brain would often get damaged; the brain size was originally just redundancy. This also fits with the astonishing plasticity of the brain: If a brain areal is destroyed, the surrounding brain areas can learn to perform the function of the missing brain part. Of course already having a greater brain meant that the additional cost of using it for more complex stuff was much lower, allowing for the evolution of intelligence.

When working on that hypothesis, you'd need to have a reason why the birds would often have brain damages, and why a larger brain with more redundancy (rather than strategies for avoiding the brain damage) would be advantageous despite negatively affecting flight.

Answer 13

To be honest, I see one of two possibilities to help an avian on that journey off the top of my head.

The first, assuming they are more like our birds, would be they become land bound, such as the ostrich or the extinct elephant bird. Where having a large brain wouldn't be a problem and the wings could become more useful as arms and hands.

The other would be if they had 6 appendages like a griffin, the front 'legs' becoming arms.

However, the appendages would be more for helping advance the species in technology. being land based would be enough enable them become very intelligent. Of course it's always possible to still have flight and be intelligent but brains are big, bulky, need lots of protection and require a lot of nutrients. So an intelligent avian species is more likely to be grounded.

Now to deal with the extra requirement of the avians actually staying aloft as a species, because of the issue of the weight of the brain, the bodies would have to change to handle it. One change would be having a short neck to keep the weight closer to the body another would be to have a very large wings to add more lift, maybe more of the body can 'morph' to help with wing surface area more like a flying wing. But with such a specialized body structure, I think they would need to be a 6 limbed animal to have limbs with dexterity to create tools.

Answer 14

Best that I can imagine, you will need wildly different environmental pressures on the planet in question.

Some possibilities:

Ocean World The planet is almost entirely covered in ocean, with the only "terrain" being large mats of organic material. The transient nature of the terrain, plus the wide open skies and seas filled with fish, would seem to favour the development of an avian race. (Or an aquatic one, or both, the two wouldn't necessarily be in direct competition with each other.)

Gas Giant A gas giant with one or more breathable atmospheric layers might lend itself to the development of an avian race. Possibly incorporating internal gas-bladders for flight.

Skyworld This one defies physical laws in some places, but a world composed of floating chunks of rock in an atmosphere would definitely favor the development of an avian sentient race.

Answer 15

Define intelligence. There are many, many, aspects which we would consider related to intelligence. Communication is often a big thing, so a very social species would see pressures to increase functions of the brain. You mention tool use, well any species whose prey can be caught easier through using tools would see advantages (with birds in particular, their beaks can and are used for tool manipulation in some species). And don't be so quick to discount wings. Analysis of the skulls of pterosaurs show they probably has well developed brains for processing information from their wings (bats may as well, I don't recall offhand). So if you are not limiting yourself to feathered birds but flying species in general, a species with skin based wings with nerve endings along the wing would develop brains capable of understanding the signals they are receiving to help them achieve a more acrobatic flight.

Answer 16

Tom's answer has one flaw; He says that elephants and dolphins don't really use tools. Compared to other fully or semi intelligent beings such as humans, elephants and dolphins (and other cetaceans) don't need to use tools as much as humans do, and don't have as much ability to make and use tools (especially cetaceans) or to carry them around permanently.

Jane Goodall revolutionized ideas of non human intelligence by observing chimps using tools, but decades earlier there were observations of elephants using tools. Charles Darwin observed elephants modifying branches and using them as fly swishes, and there were also observations of elephants modifying twigs to clean out gunk from glands in their heads.

http://www.onekind.org/education/animal_sentience/tool_use/tool_use_in_elephants/[1]

Captive elephants have been known to use keys to unlock their cages.

I think that it is time to stop thinking of only one semi or fully intelligent species of life on Earth, and instead recognizing that there are about a hundred species of semi or fully intelligent mammals on Earth.

There is a lower limit to the size of a mammal brain for the possessor to be considered semi or fully intelligent. Mammals have evolved into a wide variety of sizes. For tens of millions of years a small percentage of mammals have bodies large enough to support a brain large enough to be semi or fully intelligent. And for tens of millions of years some of those species of large mammals have evolved large brains for various reasons and have become semi or fully intelligent, often perhaps as a side effect of having such large brains.

Of course extinct or existing semi or fully intelligent species might not be limited to mammals. A few species of birds, for example, might at the least be almost semi intelligent, despite having entire bodies not much, if any, larger than the brains of semi or fully intelligent mammals, suggesting that bird brains might sometimes be more efficient than mammal brains.

So flying intelligent beings may be rarer than land or sea based intelligent beings but still fairly common in the universe.

But to me it seems an important and necessary point to make any fictional intelligent beings part of a world that has, like Earth might have, many different coexisting species of semi or fully intelligent beings, and also to have the first species to develop high technology and civilization on that planet rise tens of millions of years after the first semi or fully intelligent beings on that planet, as may be the case on Earth.