I don’t think “Lisa” from “All Famous FAQs” is an authoritative cite. The standard definition of “apex predator” is “a predator which is not prey for any other animal.” “Apex predator in its niche” isn’t really a meaningful phrase - AIUI, every animal occupies its own unique niche in the ecosystem.
Also, significantly, being an apex predator doesn’t really have anything to do with figuring out what animal is best placed to replace humans, should we go extinct. An animal that is already a highly successful predator has less evolutionary pressure to change. Our pre-human ancestors certainly weren’t apex predators - we didn’t get to the top of the food chain until we’d already evolved intelligence and advanced tool using. That is, not until we were already humans.
Rather than looking at “agility” or “stealth,” look for animals that are already working on things that set humans apart - large brain-to-body ratios, and tool use. House cats aren’t particularly advanced on either of those axis.
Having a niche that includes being picked off by coyotes is not my definition of an apex predator. An apex predator is the top predator in their whole habitat. There is no habitat except on islands, where a house cat isn’t preyed upon by larger predators.
Cats don’t actually have a niche, in the sense that they occupy a space which would otherwise be empty. They are an invasive species, in fact a scourge everywhere they live outside a cattery or house.
As far as destructive non-native mammal species goes, cats must be in the top five, with humans of course being always number one.
If cats are so formidable, why do they only spread where humans have spread them? Why hasn’t the African wildcat (what housecats were domesticated from) already conquered the world? Our domestication certainly hasn’t made them any better at hunting.
Yes, even the ferals are very successful in human-habited areas. But that’s only because we’ve actively killed off all of their competition (as opposed to our habit of incidentally killing off many other species). They already fare poorly against coyotes; think of how they’d do if the coyotes were left completely unchecked.
I would like to agree that avian dinosaurs (maybe pigeons, or corvids) would likely be able to outlast humans. I think we need to broaden our definition of technology to include non-industrial biological machines (trees, flowering plants, fungi, etc.). Humans like to harness energy by burning stuff. There might be other ways to harness energy, like engineering trees. And yeah there are insects which engineer their cities. And they’re hard to kill. We should keep an open mind…
Then I’ll change “their niche” to “insular ecosystem”, but my point is that for their size house cats are very efficient, successful predators and quite adaptable. They are present in large numbers, they don’t need humans to thrive and they can evolve to fill vacating niches if humans disappear. A number of big cat species are the apex predators of their environments, but I don’t believe they have sufficient numbers to recover, evolve and replace humans.
I see the same problem with intelligent, tool using species, like great apes. I don’t believe they have the numbers sufficient to recover and dominate.
Cats are also not the apex predator in their insular ecosystem, unless you’re specifically referring to the handful of cases where cats were introduced onto literal islands, and decimated the local population of birds and small rodents. Domestic cats aren’t even the apex predator in most human households, where they come in second to dogs.
And, much like “being a good predator,” “having a large population” is not really a factor in whether an animal could evolve to replace humans as the dominant technological species on the planet. Genetic information suggests that human populations may have dropped to as low as 2000 individuals at points in pre-history.
It doesn’t really matter. The ecological niche of a housecat is eating kibble or scrounging out of a dumpster. Once that niche no longer exists, they’ll have to venture out and compete in other niches for which they are not the optimal predator. When they go out stalking mice and songbirds, the hawks and owls that normally hunt those animals will gladly hunt a larger, more nutritious animal that doesn’t put up much more of a fight.
The answer to the question “which animal will rise after humans” is “all except human pets, pests, and parasites.”
If the question is “which animal will fill the role of general-intelligence, highly adaptable toolmakers”, the leading contender is quite obviously a member of the primate family. There’s no other animal positioned to be next in terms of intelligence and proximity to the that niche. But the big caveat is that there’s no big pressure to fill that niche. For example, dolphins are really smart, but they’re really good at being dolphins, so they’re not going to leave the ocean and start building mud huts before apes do.
Humanity only arose quite recently, and it was a great fluke, and it almost went extinct before it ever really got off the ground. We don’t have a special niche. It’s much more likely that the domain of humans will be divided up by other animals, and it’s possible that our type of intelligence may never be seen again, just like we’ll never see another brontosaurus again. Evolution has no purpose, no pinnacle, it just keeps going with whatever works.
The point being that evolution doesn’t have a speed; it occurs at the rate the environment (both physical and biological) changes, multiplied by some random factors.
No species is a sure thing to “fill the niche if humans disappear.” All contenders have some characteristics that make them more likely, and other characteristics that make them less likely to succeed. A lot will depend on the environmental conditions present when humans hypothetically disappear, and no doubt luck will play some role, too.
Raccoons, for example, have intelligence on par with cats and although they lack opposable thumbs like primates, they do have more dexterous hands than cats. But, cats outnumber raccoon >~20 to 1. Could raccoons gain the upper hand over cats? Maybe, but I don’t believe so.
Primates certainly have a greater brain-to-body ratio and intelligence than cats, but all of the great apes are endangered. Could, for example, chimpanzees expand and gain the upper hand over current broad-range species to attain world dominance? Maybe, but I don’t believe so. Remember, if the extinction of humans takes pressure off chimps, it also takes pressure off of their predators (e.g. leopards). Cats have a broad range of habitats (they’re present on all continents except Antarctica). Chimps would need a lot of luck to expand that far and wide.
The fact that the human population ~70k years ago dwindled to a few thousand before becoming the dominant species does not equate to chimps being able to do the same. For one thing, humans could have easily gone extinct at that time; their survival wasn’t a given and involved a degree of luck and conditions that may not exist today. For another thing, humans 70k years ago were more intelligent and more adept at tool-making than current great apes and therefore better able to defend themselves against predation.
And, of course, there are other species to consider with relatively high intelligence and/or tool usage (e.g. octopuses, orca, porpoises, sea otters, crows, etc.), but they have their own obstacles and limitations to contend with in order to replace humans as the dominant species.
My position is simply that cats may not be the best at any single qualification, but they have a formidable combination of qualifications that make them prime contenders for world domination in the event of human extinction (i.e. broad range, relatively high intelligence, adaptability, speed, agility, effective hunting skills, and solid and growing current population).
The family of felines has a proven track record of evolving significantly to fill a variety of niches (including alpha predator in various habitats). Sure, to become effective tool makers they would need to evolve more dexterous hands, but the current front paws of house-cats already show signs of proto-advanced dexterity (more so than dogs, for example). It’s just a hop, skip and a jump for them to evolve opposable thumbs.
I believe house-cats would also need to evolve into a physically larger sub-species in order to dominate. But, again, the feline family has a track record of producing large dominant species, so this should not pose a problem.
The future world language won’t be English, or Latin, or Spanish, or Klingon—it’ll be Meowish. I’ll bet a bowl of Kit & Kaboodle and a gram of Catnip on it.
Cats don’t need humans to survive and thrive (480-million stray cats do quite well fending for themselves). Unlike domesticated dogs, house-cats are only semi-domesticated. They’ve retained all of their hunting skills and don’t need Little Friskies® to live well.
This assumption is largely contingent on factors outside the discussion. It depends on what kind of extinction we’re talking about. Meteor? Nuclear war? Climate collapse? Who knows.
It should be noted that the biggest proximal threat to humans is civilizational collapse. Most of us depend on a fragile web of global trade that will fail very, very early in the process of climate collapse or global war or whatever. So it’s very possible we could have a mass depopulation of humanity accompanied by the flourishing of species that don’t need to sell stuff to Europe to buy stuff from China.
They don’t fend for themselves, though. They’re not making a living off hunting, they’re scrounging out of garbage cans. When the humans are gone, their food source is gone. Notice how you seldom see stray cats in the forest? There’s a reason for that.
We could have said exactly the same thing in the era of the first proto-humans. They were confined to small parts of Africa. Down to a population of 1,000 at one point. Cats were everywhere. Humans evolved into intelligent, tool-using generalists that dominated nearly everywhere. Cats did not. There’s no reason to expect that equation to go differently the second time around.
The reason, I believe is because they don’t want or need to live in the forest, when it’s easier for them to scrounge garbage cans. I’m confident if the need arose, cats would successfully expand into whatever habitat they needed to, live off the smaller wildlife and to a large degree, avoid predators.
My current cats are strictly indoor cats, but growing up I’ve had quite a few indoor/outdoor cats. They didn’t need to hunt for food (we kept them well fed), but they all hunted successfully in the forest across the street from us (and they avoided various predators). Our only cat that died during the hunt was run over by a car when he ran across the road with a baby rabbit in his mouth. Why do cats hunt when they don’t need to? Because they love it. Hunting is in their blood. Even indoor cats hone their hunting skills daily in the games they play.
Is a big factor in evolution a simple mathematical issue? In other words the more cells and gene combinations we carry the more opportunity for mutations. I can easily imagine humans branching off into a few different breeds at least and eventually new species. Under the right circumstances the selection process in humans could become supercharged.
The question isn’t whether cats are good hunters. It’s whether they can enter a niche where the job of small-game hunter is already taken and highly competitive.
Obviously wildcats exist, great cats exist. They are apex predators in their niche, but numerically they aren’t close to dominant. Why would stray housecats perform better than that? They’re specifically bred to have less of the behavioral traits that help them thrive in the wild.
The point of bringing up the human bottleneck was to point out that current population numbers aren’t a predictor of future evolutionary success. Population numbers can change wildly in a much smaller time frame than it takes evolution to induce significant biological changes. The fact that there are a lot of house cats right now, and not a lot of higher primates, is a function of an environment that has been altered in nearly every way by human civilization. Remove human civilization - change the environment - and those population numbers are going to change wildly. Would this necessarily mean that chimps are going to come out on top? No, of course not. It just means you can’t make useful prediction about evolutionary success by looking at contemporary population numbers.
I’m not sure this is even true? It’s difficult to say, because I don’t think you really understand what an evolutionary niche is, but how different are the various cat species from each other? The differences between a tiger and a house cat seem pretty minimal, outside of sheer mass. They’re all solitary predators (lions excepted) and obligate carnivores. They seem to have a rather low level of adaptability in that regard.
Again, they’re very successful in an environment that has been radically altered by humans on nearly every level, including massively reducing the numbers of most of the species that would predate house cats. They’re only on every continent because humans brought them there. Remove humans from the equation, and the environment in which they’re currently flourishing is going to change radically, in a very short period of time.
Eh, I think we are going to be hard to actually wipe out, so anything that gets us(including ourselves) is going to take a pretty significant chunk of the biosphere with it.
Mass depopulation isn’t extinction. As long as enough survive to start breeding again, we’ll come right on back.
All life is destructive to its environment. The most basic function of life is to increase the entropy of its surroundings in order to decrease the entropy of its interior. As life becomes more complex, it gains more and more ability to increase its own order, and even to expand its ordered environment, but always at the cost of greater and greater damage to the external environment.
Any species that evolves to “flourish” will be wasteful, and will have trade. They may not have places called Europe and China, but there is no reason why they wouldn’t end up with a similar economic structure where trade is beneficial to all parties involved (and detrimental to many parties not involved).
It’s not human nature that causes out of control unsustainable growth, it’s the nature of life itself, and any species that replaces us will tend to follow the same path.
But they don’t fend for themselves. They still depend on humans to keep wolves, bobcats, bears, and cougars away. Would they still survive without that help? Some of them, probably, but far from 480 million of them.
