There are numerous theories about the apocalypse, life after us, life after society. Many movies have been made, many books written, many zombie defense kits compiled… but what about after the humans are gone? Whether we go out from nuclear annihilation, global warming, mass epidemic of incurable infectious disease, or alien warfare, one thing is for sure; humans cannot exist forever.
But does our extinction really mean the end? Is there a species that will take our place? Does it exist now? Or is it yet to evolve into existence? We put the question to a biologist, an environmentalist, and a paleontologist. We learned why ‘species’ isn’t a good term after all, and that cockroaches, while survivalists, are not going to start rebuilding civilization after our extinction.
Professor of Environmental and Occupational Health at George Washington University, former executive director of the Harvard Center for Risk Analysis, former assistant administrator for the EPA’s Office of Research and Development, former President of the Society for Risk Analysis
Imagine what the planet would be like if an alien death ray or a global pandemic wiped out the human race. In the short term, all of the ways we manage nature, like farming, domesticating animals and collecting sewage would break down. Cattle and chickens (and even our dogs and cats) would probably not last very long without human intervention. A natural order of predators and prey would spread.
Over time, nature would reclaim the landscape. Think of the Mayan temples we find today as mounds of green in the jungle, the structures buried under soil, trees, and vines. Of course, some human structures would be visible for a very long time. Roman aqueducts and the Egyptian pyramids are signs to us today of civilization thousands of years ago. The longest-lived features might be giant and technological, like dams or power plants, or mundane and durable like metal coins or plastic lunch boxes.
Life on Earth would continue, creatures hard to imagine would evolve and maybe, just maybe, a new intelligent species would arise. They would just have to stay on the right side of the aliens.
Biologist, Research Fellow at the National Institutes of Health
I’d like to argue that humans, nor any other multicellular organism, do not reign supreme. In terms of the ability to inhabit any and every ecological niche, reproductive capacity, and seniority here on earth, bacteria are the champions. In fact, the only reason animals evolved the ability to reproduce sexually is to recombine our gene pool in such a way that we would be able to coexist with bacteria instead dying off from infections in any given generation. Bacteria inhabit every inch of the earth, including deep oceanic vents, the most frozen-over polar caps, and our bodies! We actually coexist with a huge diversity of bacteria on and in our bodies in a way that helps both organisms to survive. Not only are broad-spectrum antibiotics not the answer to a specific bacterial infection, they have negatively selected for the pathogenic strains of antibiotic resistant bacterial strains that will actually kill the humans on the planet if we don’t stop this form of self-destruction. So put down the hand sanitizer and concede to being a home to our prokaryotic friends.
However, if we are assuming that humans reign supreme on earth… if we were to cease to exist, I would argue that the next multicellular, eukaryotic group of organisms that would dominate would be the arthropods (animals with joined legs and exoskeletons), which include insects, crustaceans, arachnids, and myriapods. They are the most diverse and abundant phyla, or group of organisms, on earth. The reason that I am not narrowing it down further to a specific species is because this group, that have common characteristics of evolutionary resiliency and complex social behaviors, actually branch off into new species the process of adapting to the huge range of ecological niches present here on earth. “Reigning supreme” in nature comes down to survival. More specifically, will your genes live to see the next generation? Because of their ability to adapt to changing ecosystems, new ecological niches, and have the ability to reproduce both sexually and asexually, I would say that the arthropods are there to stay, forever. More interestingly, the social dynamics of seemingly simple “bugs” are actually quite intimidating. If you look at a single ant, it seems to travel in a “random” path. If you look at the entire ant colony, they actually coordinate these seemingly random movements in such a way that they can accomplish seemingly impossible tasks, like building, organizing, and bringing items back to their colonies. All of this on top of having an incredibly complex social hierarchy that is actually governed by their biology. We’re not as far off from One Hundred Years of Solitude as you’d think.
Ecology and Evolutionary Biology student at University of Michigan
The exciting part about evolution is that there are a whole new set of animals we have not been able to imagine in our wildest dreams that are waiting to evolve in the future. Animals are constantly evolving, but the speed of evolution depends on if the environment is changing or not.
Well, in some future, if the human species were to suddenly die out in some giant nuclear war that happened to only affect humans, that environment would change rapidly. The extinction of the human race would quickly create a brand new habitat for a lot of animals.
We know what happens when there is new land to be explored - this happens a lot with mass extinctions (such as the dinosaurs) or rapid environmental changes (like the Cambrian explosion). Oftentimes, there is a phenomenon called adaptive radiation. In layman’s terms, adaptive radiation could be compared to the fastest kid getting to the unsupervised cookie jar and stealing all the cookies. All of a sudden, an animal has a new environment that is PERFECT for this animal and its population explodes! It rapidly diversifies! IT’S EVERYWHERE!!!
And other animals during sudden changes all of a sudden die out. They can’t compete.
We can’t really predict which animals are going to succeed, but I could make a guess.
I am fairly sure the insects will make it. Insects are about 70% of the world’s diversity right now and they have been through a lot. Ants are not going anywhere anytime soon.
What people might not consider is that most animals on this planet right now are domesticated or farm animals. Your pets might do okay (the bigger ones especially… and cats. Cats are smart; your chihuahua is dead) and will probably outnumber the coyotes and fare well. Cows, chickens, and pigs will feed the predators. Which farm animal will compete is unknown (but my money’s on the pigs).
We have a huge dearth of any animal at the top of the food chain - both in the oceans and on land. My hope is that some really new awesome giant raccoon will take over as the top predator and RULE AMERICA.
Paleontologist at the American Museum of Natural History in New York City
Besides the usual suspects (cockroaches, rodents), I’m willing to bet that many bird groups will flourish in a post-human terrestrial world. Although it’s nearly impossible to say which particular species will be successful, birds are diverse (~10,000 species compared to ~5,500 mammal species), have a global distribution, and show a unique set of adaptations. Most obvious is their ability to fly that would allow them to disperse across a wide geographic range looking for resources. As with mammals, they are also homeothermic (“warm blooded”), able to adapt in a wide range of climates and habitats compared to ectothermic amphibians and reptiles. Also like mammals, birds have very large brains for their body size, and understanding how the enlarged brains evolved in birds is a focus of a research team here at the museum. The enlarged brain allows sophisticated behaviors such as tool use, complex social structures, song learning, and even acclimation to urban environments in some birds. Lastly, if a catastrophic event triggered the end of humanity, birds have a good track record in surviving extinction events, including the one 66 million years ago that killed off the “dinosaurs.” Why the quotation marks? That’s because all modern birds that you see today are a surviving lineage of dinosaurs (similar to how humans are a member of primates). If birds do take over a post-human world, then it would signify the second “Age of Dinosaurs.”
million years ago in northeastern China, lived the oldest known relative of modern birds, the archaeonithura meemannae.
million years ago lived the oldest and most primitive known bird archaeopteryx, but has no living descendants.
species of birds are known today