Animals die all the time. Sometimes so much so that entire species go extinct – a terrible loss for biodiversity and our world’s ecologic systems. A National Geographic article last year prefaced a discussion about species going extinct by pointing out that “more than 99 percent of all organisms that have ever lived on Earth are extinct.”
Over the millennia that humans have roamed the Earth and impacted our planet, our species has greatly contributed to the process of extinction. In recent years, fears have emerged that industrialization is relegating unique lifeforms to the dustbins of evolutionary history faster than at any time in the past – something like 100 to 1,000 times the so-called “background rates” of natural extinction.
One can quibble over the precise rate at which human activities are causing the extinction of other species. The International Union for Conservation of Nature (IUCN) maintains a list, the Red List of Threatened Species, which assesses and monitors the development of species, and classifies the threat to each of animal according to a six-category scale. Out of the 120,000 species assessed, some 30,000 are deemed “threatened.”
For perspective, estimates suggest that there are some 9 million species on the planet. Most of those species are not even named, let alone threatened with extinction. The IUCN explicitly admits the difficulty of trying to determine how many species are actually going extinct:
“Since extinction risk has been evaluated for less than 5% of the world's described species (see Table 1), IUCN cannot provide a precise estimate for how many of the planet's species are threatened.”
Many species that were wrongly believed to be rapidly sliding towards extinction have seen major improvements to their numbers. For example, the Bengal Tiger is deemed Endangered, with a reported 2,000-3,000 individuals in the wild. However, the government of India, the country with the majority of the world’s tigers, reported in 2018 that there were 2,967 wild tigers in India alone. That was a 33 percent increase over 2014 numbers.
In late 2018, the IUCN reported that the threat to Fin Whales, the second-largest mammal on the planet, and the Mountain Gorilla, that iconic symbol for human predation, had subsided somewhat, and both species were downgraded to a lower risk category. The same is true for the Snow Leopard of central Asia, which was recently downgraded to Vulnerable, and the African Elephant.
It’s difficult to map all the world’s species – or even most of them. For instance, the Census of Marine Life, a ten-year effort to map and record the many lifeforms of the sea, found thousands and thousands of new marine species that we either thought were extinct or didn’t know existed in the first place.
Because of their size and observability, mammals and birds are easier to count than crustaceans at the bottom of the ocean or beetles in the Amazon. Judging by the rate of extinction of mammals, the forewarned avalanche of extinctions is still a few centuries off, even if the most extreme estimates of current pace of extinction are accurate.
Besides, in the last 500 years only some 80 mammals are recorded as having gone extinct. In his book, More From Less, Andrew McAfee, a board member of HumanProgress.org, discusses how relatively rare recorded extinctions are – with some 530 across all species in the last five centuries. More importantly, he notes, the rate of extinction “appear[s] to have slowed down in recent decades; for example, no marine creatures have been recorded as extinct in the last fifty years.”
Matt Ridley, another board member and frequent contributor to this site, argues that despite the human population doubling in the last half-century, “the extinction rate of wild species, especially in the most industrialized countries,” seems to have fallen rather than increased. While absence of evidence isn’t the same as evidence of absence, and there might be millions of unrecorded species in the world’s oceans and tropical forests, the most aggressive claims rest on shaky foundations.
McAfee reports that humanity is now actively helping biodiversity in at least three major ways. First, with the power of genetics and cloning, we might soon be able to bring back animals that have unfortunately gone extinct. Second, by use of technology and concerted human efforts, we might eradicate invasive predators from islands where they are threatening local wildlife. The New Zealand’s “Predator Free 2050” project and the extermination of invasive rats and mice on the South Georgia islands in the southern Atlantic are good examples of such efforts. Third, by cross-breeding and selecting plants and species for desirable traits, humans have effectively created new species. The nature writer Stewart Brand concludes that, contrary to popular opinion, “we are re-enriching some ecosystems we once depleted and slowing the depletion of others.”
Another stunning discovery are the so-called Lazarus species or animals that were considered extinct, but which have made re-appearances. In 2010, the Australian scientists Diana Fisher and Simon Blomberg reported that more than one-third “of mammal species that have been classified as extinct or possibly extinct, or flagged as missing, have been rediscovered.” Between 1981 and 2001, scientists rediscovered 89 different plant species once believed to have been extinct in Australia alone.
The Tamaraw, for instance, a buffalo-like animal native to the Philippines, was believed to have been extinct since 1992 – until biologists spotted a group of them in a wildlife sanctuary in Occidental Mindoro last year. Tortoises, notorious for their long lifespans, have also had their fair share of returns from the dead. The Fernandina giant tortoise, long believed extinct, made a re-appearance last year on the Galapagos Islands. The IUCN re-classified the tortoise from extinct to critically endangered, and the female tortoise was taken to a breeding center, while the search for more individuals of her kind continues.
In many other domains, extinct species keep turning up: from seabirds and flightless birds in New Zealand that haven’t been spotted for centuries, to the world’s largest bees in Indonesia, to Colombian toads and caimans not seen for decades. Extinct species, it seems, make for great rediscoveries.
Slowly, humans are making amends for our past excesses. What’s clear is that nature’s resilience is stronger than we thought. Many species can adapt to changed circumstances, migrate to different habitats, and more importantly, live and operate where they aren't directly observed by scientists and wildlife biologists.
Conservation efforts that breed endangered species in captivity before re-introducing them in the wild are clear indications of human ability and desire to repopulate the earth with species threatened with extinction. With technological advances, (re-)discoveries of species, and continued economic growth that returns more land to nature, the onset of further wildlife extinctions seems far-fetched.