Human-Caused Ecological Devastation Theme Analysis

In speculating about humanity’s ancient past, Sapiens author Yuval Noah Harari argues that humans are the Earth’s deadliest species. Harari thinks humanity’s ancestors, Homo sapiens, evolved advanced cognitive skills so suddenly that they jumped to the top of the food chain before the rest of the ecosystem had to time to recalibrate to the new threat. Harari contends that Homo sapiens killed off at least six other human species (including Neanderthals), drove more animal species to extinction than any other creature on Earth, and, in modern times, continues to inflict mass cruelty on other animals through the farming industry. Harari concludes that whenever humans spread into a new territory, death and cruelty follow for other animals. Harari suggests that if humans don’t curb our cruel and dominating tendencies, we might one day be the only animals left. Harari concludes with a warning for humanity to curb our reckless domination of other species and think more carefully about the devastating effect we have on Earth’s ecosystem.

According to Harari, Homo sapiens have been responsible for the extinction of nearly all large mammals on Earth for over 70,000 years, showing that we’ve been the world’s deadliest species. When Homo sapiens evolved new cognitive capabilities around 70,000 years ago (the Cognitive Revolution) and began spreading around the globe, they drove at least six other human species (including Neanderthals) to extinction. Harari contends that our ancestors displaced and killed off even the mammals that were most like us, showing that our human species is deadly and combative.

Harari argues that there’s a pattern in history: every time Homo sapiens shows up in new territory, large mammals go extinct, suggesting that we are responsible for the most extinctions than any other creature on Earth. Harari thinks the Cognitive Revolution happened so suddenly that other animals didn’t have time to develop the instinct to avoid Homo sapiens. Many large mammals in isolated ecosystems—like Australia’s—didn’t fear animals that were smaller than them, because they hadn’t had exposure to small, deadly animals before, leaving them unprepared for the havoc that Homo sapiens would wreak on their species when they first arrived in Australia 45,000 years ago. Homo sapiens ended up killing off 23 out of 24 of Australia’s large marsupial mammals within a few thousand years, suggesting our ancestors were nature’s deadliest threat in that ecosystem. Australia’s mass extinctions weren’t an isolated incident: mass extinction of large mammals also followed in other ecosystems when Homo sapiens spread to those areas, including the Americas (14,000 years ago), the Caribbean (7,000 years ago), and Madagascar (1,500 years ago). To Harari, the evidence shows that ancient Homo sapiens were “ecological serial killers,” as they swiftly became the deadliest animals in every environment they inhabited.

Harari thinks that modern humans are even more deadly and cruel to other species than our ancient ancestors were, citing continued extinctions in the wild and cruelty in the farming industry. He warns against continuing on this path, suggesting that humankind could soon be the only animals left. Harari argues that humans continue to cause extinctions as they spread further into the Earth’s ecosystems. He thinks the “large animals of the oceans” are next, because “many of them are on the brink of extinction now as a result of industrial pollution and human overuse of oceanic resources.” Harari predicts that at the current pace of oceanic pollution, “whales, sharks, tuna and dolphins will follow the diprotodons, ground sloths and mammoths to oblivion.” Harari thus stresses that in pursuing our own interests, humans are having a devastating and irreversible impact on the planet. Harari thinks it’s a mistake to assume that other species (notably agricultural animals including cows, pigs, and chickens) are thriving in numbers as a result of human industry. He contends that although their populations have never been so large, their lives have also never been so short or miserable. For example, chickens can live for up to 15 years roaming in the wild, but most chickens today are only alive for a few weeks in cages before they’re killed for meat. Harari argues that modern humans are not only deadly, but also pathologically cruel to other animal species on Earth, making us even worse than our archaic ancestors. Harari concludes that humanity’s track record with other animal species is deplorable, and he predicts that eventually, there’ll be no large animals left except “humans themselves, and the farmyard animals that serve as [our] slaves.” Harari thus warns humanity about the dangers of our unchecked domination of other species, arguing we’ll regret our actions when we’re the only large animals left on Earth.