Once thought to be legendary creatures, the woolly mammoth became extinct around 10,000 years ago, although a few isolated populations clung on for another few thousand years. The extinction of these lovable giants is a story that is understood better than that of many other now-extinct species.
Early humans and mammoths coexisted for a period of time, and humans used the bones and tusks of these animals to make tools and art. Similar in size to the African elephants that exist today -- 4-6 metric tons of animal – the wooly mammoths were well-adapted to roam the steppes of Eurasia and North America during the last ice age. Unlike modern elephants, the wooly mammoths had smaller ears and tail in order to minimize frostbite.
The end of the ice age period between 14,000 and 10,000 years ago blew a devastating blow to the woolly mammoth population. Scientists agree that environmental factors – that is, the changing climate – had shrunk the habitat of these animals. Hunting was another significant factor in their disappearance, although it’s unclear to what degree.
As increasing temperatures began to dry out lakes and water supplies, the mammoth population was left to die a gruesome death, that of thirst. Rising sea levels resulted in oceans subsuming some of the existing lakes, while sea water flowed into the remaining lakes. Crowding around the remaining water sources, the mighty animals contributed to sediment erosion by milling around the water sources, destroying vegetation, and diminishing the water supply even faster. A modern elephant needs 70-200 liters of water daily, and it is likely that mammoths required the same, which is why their demise came quickly.
A few isolated populations of mammoths survived the environmental changes and escaped the fate of being hunted for their ivory tusks. Most notable, mammoths on Wrangle Island off the coast of Siberia disappeared only 4,000 years ago. Their story is different.
Because their population was small and the reproduction rates low, scientists believe that inbreeding resulted in a lack of genetic diversity. DNA mutations affected fertility and survival, proving disastrous for these fur-covered giants. Some scientists have called this the “genomic meltdown.” For example, the mammoths lost their sense of smell, which made it all the more difficult to locate food.
While mammoth fossils have been preserved well and have allowed scientists to peak into the past, other animals that disappeared around the same time are more of a mystery. Still, scientists hypothesize that climate change was one of the more significant reasons for the extinction of the saber-toothed tiger, the Irish Elk, and the chalicotheres, an animal that looks like both a zebra and a gorilla but is most closely related to horses, tapirs and rhinos.
And it’s not just tens of thousands ago: because of climate change, deforestation and hunting, there are animals that have gone extinct in the 20th century. Among them the barbary lion, one of the biggest lions to have ever existed, which became extinct in the 1940s; one of the largest mammals in Mexico, the Mexican grizzly bear, which was exterminated by 1969; and the beautiful Fijian Levuana moth, with its gray-blue wings and golden belly, which became extinct in 1994.
The 21st century has already seen the loss of the Pinta Island tortoise in the Galapagos, Spain’s Pyrenean ibex, the Formosan clouded Leopard, endemic to Taiwan, China’s Yangtze river dolphin, Costa Rica’s golden toad, and the adorable furry Christmas Island pipistrelle bat in Australia.
What comes next is even worse. The International Union for Conservation of Nature (IUCN) estimates that up to 0.1% of all species are becoming extinct every year. It may seem like a small number, but since there are between 2-100 million wildlife species, with more discovered every year, this means an annual extinction of 200-100,000 species.
On that list currently are the Asiatic cheetahs, of which fewer than 100 remain in the wild; the mountain gorillas, which number 300, and Indian elephants. Even though they are not extinct yet, small populations risk genomic meltdowns, and the numbers must go up if we are to see these animals thrive again.
Humans need to take a step up to actively protect these animals, and we’ve seen that it is possible. Following global conservation and protection efforts, the IUCN now downgraded the risk for pandas, which number 2,000, from extinct to vulnerable. And by the way, after almost a decade of no mating, two pandas finally mated successfully in a Hong Kong zoo in April 2020, while the zoo was on lockdown due to coronavirus. Perhaps there’s something to be said for letting the animals do their thing, too.