Evolution of predatory elves

Question

One concept I've toying with for a while is the idea that elves are a species of Homo that have adapted to a more predatory life style. With the idea that their agility and strength is derived from them hunting game while still using using tools and consuming plants, they would prefer to hunt other organisms for sustenance.

The traits I came up with are:

• Taller than Homo Sapiens, around 6-7 feet on average though height does vary immensely according to genetic, environmental and medical reasons.
• Are around 1.5 times stronger than humans while having a lither frame and higher muscle density and other adaptations for strength. Increased ATP production, Denser bones to handle stress etc.
• Greater stamina and speed than humans.
• Have a higher blood pressure to feed organ systems.
• Are less tough than humans. i.e. they get hurt more easily.
• Need to eat more
• Can enter torpor although it is highly risky
• Larger eyes closer to that of a Neanderthals
• Pointed canines and incisors
• Is able to interbreed with humans

Otherwise these elves look and behave very similarly to humans and are an offshoot of the Homo Sapiens lineage.

This is where I started running into contradictions regarding their evolution. It's thought that our species got so lithe in comparison to Neanderthals because we both exhausted prey while having a greater emphasis on throwing weapons, i.e. the Atlatl, whereas the Neanderthal relied more on running down prey and utilizing thrusting spears more often in their hunts, conferring them a much stouter but stronger build than Homo Sapiens.

Now we get back to the concept of the predatory elf I outlined in the beginning. The issue in this case is that none of the things I listed seem to make sense when put together in the context of hominid evolution. Why be stronger than a human when you have a longer reach allowing more power for a throwing implement when the extra strength simply demands more food to be consumed, potentially lowering the fitness of the individual during lean times? Additionally, what benefit would skewing the anatomy to gain more in performance while sacrificing toughness while hoping that the increased agility and reaction time can compensate?

In short: What evolutionary pressures could lead to a elf-like hominid as described above despite the amount of seemly contradictory traits?

P.S. I have considered predation of other hominid species and let aggressive mimicry play out. But that would clash with the vampires of the setting, which mind you, are a offshoot of the elven lineage that needs to consume the flesh/brain matter of other hominids due to a genetic disease causing hormones deficiency and drinking blood for food conservation.

They basically take the role of dark elf/"undead" vampire slavers who raid other species for both labour and food.

Answer 1

As a slight modification to your proposal, I'd like to offer up an alternative hominin as an avenue of exploration:

(image credit Giles Laurent via wikipedia)

Consider:

• reasonably intelligent
• occasional predator
• stronger than a human

Now, you asked

Why be stronger than a human when you have a longer reach allowing more power for a throwing implement when the extra strength simply demands more food to be consumed?

Well, consider that the answer might be brachiation. Human ancestors evolved towards bipedalism which is useful when you want to expand into biomes with fewer trees, like savannah. Elves on the other hand have been strongly associated with trees and woodland. That strength is there so that they can move through the canopy of densely wooded areas quickly and efficiently. They can climb and descend rapidly and make use of movement in three dimensions which makes it easier for them to exploit things that live up tall trees... various kinds of fruit, but also bird eggs and other arboreal reptiles and mammals.

A human would come off very badly in an unarmed fight against a chimp, that's for sure. They're strong, and they have some fairly serious dentition compared to humans: (source pxhere, CC0)

This doesn't hit all your requests, of course... I'm sure you could handwave in really long, tall chimp descendants if you wanted, but your other requirements become trickier. Interbreeding with humans seems especially problematic, though maybe you could have a mule-like situation going on (some settings have half-elves be explicitly infertile, as a precedent). Torpor is discussed in Monty Wild's answer. Handwave until it fits your needs.

They basically take the role of dark elf/"undead" vampire slavers who raid other species for both labour and food.

Preying upon intelligent species is tricky. Everything that was a significant threat to humans and proto-humans has either been exterminated or rendered largely harmless (and probably could be exterminated, they just don't need to be). If nothing else, a human takes aaaaaages to reach full adult size, and they have an inconvenient diet as they can't just subsist on grasses and leaves and so on. Almost any other kind of livestock is going to be a much more effective source of calories, and is much less likely to form a warband and engage in some slash-and-burn warfare to exterminate you. You can have a human as a treat, though. Just not too many.

Slavery is of course something that regular humans have practised for a very long time. So long as your elves are as bad as humans (and arguably less so, if they only enslaved non-elves) that seems fine.

Answer 2

You can't get there from a basic hominid. You might be able to do it with genetic engineering, but you wouldn't have anything compatible with a human after that.

The problem is:

• Are around 1.5 times stronger than humans while having a lither frame and higher muscle density and other adaptations for strength. Increased ATP production, Denser bones to handle stress etc.

and

• Greater stamina and speed than humans.

Muscle density is pretty much identical in all hominids. Changing that (by which I mean changing the Actin/Myosin proteins of the muscles which makes them work) would probably require a lot of evolutionary backtracking or a generational disadvantage, and that never happens. You can increase strength by changing joint lever ratios, but stronger = slower and weaker = faster. That's a law of physics.

As for stamina and speed, they're also somewhat contradictory. The faster you run, the less time you can run for, due to energy usage and atmospheric drag. You might be able to achieve stronger and faster by being bigger, but bigger and heavier means that it takes more energy to run, which tends to reduce endurance.

• Can enter torpor though it is highly risky

Primates don't do this as far as I know. Evolving it might be tricky, though it need not be risky.

• Need to eat more

Predators are often able to swallow large amounts of meat. Alternating gluttony with starvation is easily achieved.

• Larger eyes closer to that of a Neanderthals
• Pointed canines and incisors

These shouldn't take too much to evolve.

• Is able to interbreed with humans

This is the trickiest bit. As long as the chromosomes match reasonably well between the two, and there haven't been any incompatible genetic changes, it should work. However, allowing interbreeding is a barrier to speciation. These elves are going to have to be isolated for a good few hundred thousand years to achieve these differences.

So, despite all the 'easy to achieve' things, you can't evolve these elves from humans at all. You're going to have to keep muscle density the same as every other mammal, and change other things like lever ratios and/or total muscle mass.

Alternatively, ditch the science-based requirement and go with fantasy instead. It's a lot more forgiving.

Answer 3

One thing that always bugs me when I read any fiction containing fantasy species where evolution is a mechanism present in the world is the fact that ecological exclusion never seems to be something the author considers. Exclusion is the phenomenon whereby if you have two species competing for the same niche, one will always eventually outcompete the other. You can not have two species fighting over the same resources in perpetuity without one of them either dying out, switching to a new niche, or "partitioning" the existing niche into two more specialized niches. Sapience, however, is not a niche, and so, while very similar sapient species like humans and neanderthals can not coexist perpetually, two species with very different lifestyles, say an arboreal and ground dwelling species or a nocturnal and diurnal species or a subterranean and surface dwelling species, could evolve side by side without competition ever reaching a point where one completely displaces the other. Whenever I see humans and elves in fantasy, the elves are always just better humans, and in a world with better humans there would be no humans.

So if you want to have elves coexisting with humans in a way that makes evolutionary sense, those elves need to have a lifestyle different enough from the human way of life that it minimizes human-elf competition. Some of the traits you want them to have, like large eyes, could arise in a nocturnal species while others, like a longer more lithe looking build despite greater physical strength, could arise in an arboreal species that spends most of their time in the tree tops. I think something like the Elder Scrolls Bosmer, hypercarnivorous wood elves raining death on their foes from the treetops, could be a good fit for a species that could evolve alongside humans without replacing them.

Just one note I wanted to add regarding this is that these sorts of ecological considerations only really apply to sapient species in the early stages of their development, such as when we encountered neanderthals, because ecological factors have to be the primary issues at play to not complicate this issue. Once you have full blown civilizations, different disciplines become optimal for making predictions about their behaviors, but if we are talking about how these species evolved, barring a geographical barrier preventing contact until their civilizations were already in an advanced state, how they avoided the fate of the neanderthals and denisovans is something I've always thought was lacking in these sorts of "what if a planet had multiple sapient species" worlds. What happened to our cousins isn't just an unfortunate accident. It's principle that has applied to interspecific encounters since they started happening. In order to exist in the same ecosystems, different species need to be seeking different resources in different ways, or any marginal advantage, no matter how slight, will lead to one edging the other one out over time.

Answer 4

You're going to run into some square-cube law issues and problems related to biomechanics and engineering safety factors, and those are going to cause significant issues for hard-science:

• Faster & stronger overall, plus longer, thinner limbs means that the torques and stresses placed on the elves' bones by their own muscles are going to be a lot closer to the limit of what bones can handle. If you also want the elves to be more athletic, then the bones are going to need to be heavier. At some point, your elvish bones can't handle the elvish muscles. At that point, there's (at best) zero evolutionary pressure to go further in the direction you're suggesting. Humans already get a lot of sports-related injuries if they're not careful about stretching routines and physical therapy. Your elves will amp that up.
• If you want the elves to leap into / safely fall out of trees and be overall much more athletic than humans, they'll probably need to weigh more and be thicker-boned, not just longer & thinner. Similarly, if they can crush / bite through human bones, they want not just bigger teeth, but heavier jaws, stronger attachment points for the jaw muscles, thicker muscles, thicker tendons & ligaments, thicker skulls to handle the stresses from the oversized jaws & heavy-duty chewing, more robust necks & shoulders to support the larger heads, etc.
• If they're eating more per pound than humans, they're also burning more calories on average - so presumably have a higher body temperature. They'll need ways to shed that heat so they don't cook their brains or other internal organs during periods of heavy exertion. Maybe they've got low (compared to human) limits on their endurance, or maybe portions of their body & brain shut down during exertion to conserve energy and generate less heat. Maybe they're really good at sweating or otherwise managing heat. Long & thin body plans help here, as does a torpor akin to that of hummingbirds.

One way around the above is to build their muscles & bones out of different materials - but that's a harder sell for "evolved relatively recently from a common ancestor". Similarly, you could try to engineer cooling systems that don't rely as much on sweat as what humans have. Maybe copper / aluminum threads their muscles, helping to conduct heat away from the core and adding strength that most organic materials lack. (But how would they get substantial amounts of such material in a primarily meat-based diet? And how much would they have to re-evolve digestive, regenerative & circulatory systems to get such materials where they need to go?) Maybe they have large flaps of skin (like elephant ears) that act as heat sinks.

Maybe they're very limited in climates where they're active, or in what they eat.

The harder you want the science to be, the more concerned you'll need to be about tradeoffs between weight, strength, agility, injury rates, thermal regulation, etc.

Answer 5

One way to get around some of the contradictory/ unlikely physical characteristics of the elves, as reported by other answers, is to switch which species has a different size than in reality. Instead of the elves being larger than humans they are "human-sized" and the "humans" are shorter and a little more stout.