What Could Earth After Humans Look Like if Octopuses Take Over?

The prospect of life carrying on across Earth without humans is hard to comprehend. Although our species has existed for only a comparatively brief stretch of the planet’s history, we have transformed it in innumerable ways, leaving a “human fingerprint” over every part of the land and oceans.

Even so, Earth’s past makes clear that no species endures indefinitely. Thinking about a future in which we are absent may be sobering, yet it also raises compelling questions about what could take our place.

For thousands of years, humans have sat at the heart of ecological transformation on Earth. Through our settlements and inventions, we have altered woodlands, seas and even the atmosphere.

However, many scientists argue that nature would adjust after we disappear. That prompts questions over which creature – or what form of life – might fill the position we leave behind.

Earth after humans

Professor Tim Coulson of the University of Oxford has devoted years to researching biology and evolution. In his view, humanity’s disappearance might create opportunities for unexpected species to assume Earth’s ecological functions.

His book, The Universal History of Us, follows the whole history of life before focusing on one remarkable forecast of what could happen next.

Evolution is among the book’s key subjects, and he defines it as the “gradual change in living organisms over time as they better adapt to their environments.”

He stresses that “most mutations are harmful, but a few provide a survival or reproductive advantage.” Since genes are inherited, mutations that offer these advantages spread through populations over successive generations.

Natural selection and change

Coulson regards mutations as the force that propels life onwards, despite their potential dangers. Nevertheless, he cautions readers that no species lasts permanently.

“Extinction is the fate of all species, including humans, although let’s hope our demise is far in the future.”

This may be an uncomfortable thought, but it also highlights that every organism, however successful it becomes, ultimately reaches its end.

Coulson’s perspective comes from years spent examining how species develop, endure and at times die out. “I started to wonder what species might take our place if humans, and our close great ape relatives, were to die out,” he says.

With humanity no longer present, Earth’s ecosystems might regain equilibrium, potentially giving new organisms an opportunity to occupy vacant ecological niches.

New forms of intelligence emerge

No one can say whether the next dominant life form would resemble humans. Coulson suggests that “new forms of intelligence and complexity could emerge in unexpected ways.”

A future species could therefore devise technologies and answers that are entirely different from anything we are currently able to imagine.

Primates are often considered the most probable successors, but Coulson is not convinced.

“Primates depend heavily on strong social networks,” he explains, along with the idea that “they engage in activities like hunting, grooming, and defense, which are essential for their survival. These constraints might help them struggle to adjust to a world undergoing dramatic ecological shifts.”

Potential successor to humans on Earth

Rather than our primate relatives, Coulson proposes a candidate many people may find surprising: the octopus. He draws attention to its intelligence and capacity to adapt.

“Their ability to solve complex problems, communicate with one another in flashes of color, and manipulate objects suggests that, given the right environmental conditions, they could evolve into a civilization-building species.”

He adds, “their advanced neural structure, decentralized nervous system, and remarkable problem-solving skills make several species of octopus well suited for an unpredictable world.”

Octopuses are already known for their ingenuity and slight mischievousness.

“Some individuals even escape from their tanks at night in some research centers, visiting those of their neighbors, believe it or not,” Coulson says. They have been observed using tools, opening jars and showing curiosity.

Life underwater

Should humans vanish, the oceans could become still more important to Earth’s future. While land animals have generally occupied the highest places in the food chain, Coulson identifies a major obstacle for octopuses.

“Octopuses are unlikely to adapt to life on land due to their lack of a skeleton, which makes swift and agile movement out of water challenging,” he explained.

“With evolutionary advances, it is possible, if not probable, that they might develop ways to breathe outside of water and eventually hunt terrestrial animals like deer, sheep, and other mammals – assuming they have survived the catastrophic event that drove humans extinct.”

It may sound far-fetched, but Coulson is illustrating how evolution can send life along routes that initially appear impossible.

What would octopus-Earth look like?

Octopuses could potentially create underwater dwellings, develop fresh ways of engaging with their environment and perhaps eventually extend their reach above the waves.

“Would octopuses build vast underwater cities and come onto land wearing breathing apparatus to shoot a deer? We’ve no way of knowing,” he says.

Nobody anticipated that early primates would gradually become two-legged humans equipped with sophisticated technology.

Coulson believes that “random mutations, unforeseen extinction events, and population bottlenecks can all significantly influence the trajectory of evolution.” In other words, the future remains open, influenced by innumerable factors that scientists cannot completely foresee.

Impossible to know, fun to think about

“The future of life on Earth is shaped by countless variables,” he points out. Evolution could follow unusual routes; some possibilities may never materialise, while others may unfold before our eyes in unexpected ways.

“But could octopuses replace humans – and potentially also primates – if they were to die out? Absolutely. They could become the brains of the sea.”

At present, it remains a fascinating thought experiment: aquatic invertebrates managing a planet formerly ruled by upright mammals.

Imagining Earth without humans

Coulson does not present this future as unavoidable. Rather, he offers it to show how nature could reorganise itself in humanity’s absence.

Earth’s history contains numerous cases of life surviving enormous disruption. Intelligence of some sort may emerge long after humans have disappeared.

His book highlights evolution’s ability to create forms and behaviours that appear unusual from a human viewpoint.

This speculation invites us to consider how fragile our own position on the planet may be. Humanity belongs to a story that started long ago, while life will continue to progress, step by step.

The complete interview appeared in The European.