Info Bites: 10 Casualties of the Holocene Extinction Event

In this week’s Info Bites, we’ll be taking a look at ten of the many casualties of the so-called Holocene extinction event, circa 11,700 BC to present, something that, sadly, we are partially responsible for.

The last 12,000 years make up the Holocene epoch, which began with the end of the last ice age. Although anatomically modern humans have been around for far longer than this, the Holocene, which continues to the present, saw the spread of human migration beginning with the Neolithic Revolution and the birth of human civilization. However, we are also living in the midst of the most devastating extinction event since that which killed off the dinosaurs 66 million years ago. Known as the Holocene extinction event, this is the sixth extinction event in Earth’s history, and this one can largely be attributed to humans. Following are 10 of its casualties:

#1. Dodo

George Edward

A dodo, accompanied by other Madagascan bird life, depicted in a painting dating from 1759.

The dodo only ever lived in a very small area, that being the island of Mauritius. The large flightless bird was approximately three feet tall and weighed up to 47 pounds. The dodo was widely documented by explorers and settlers during the 17th century, but it was declared extinct in 1662. The bird was unusual enough in appearance that it was even transported abroad to display in zoos in Europe, and many contemporary paintings exist to give people a good idea of what the animal looked like. Although there is no conclusive proof that humans caused the dodo’s extinction, it seems likely that their being flightless and few in numbers made them easy prey for sailors.

#2. Thylacine

Henry Constantine Richter et al.

A nineteenth century painting of the then extant thylacine.

More popularly known as the Tasmanian tiger, the thylacine was not actually a feline at all. Instead, it was a marsupial like koalas and kangaroos, albeit with an appearance more like that of a wolf crossed with a wild cat. The thylacine was last seen in the island of Tasmania south of Australia and, previously, areas of mainland Australia and Papua New Guinea. The death of the last Thylacine in Hobart Zoo in 1936 makes it by far the most recent extinction in this list and, tragically, its demise represented the very end of that family of animals – it has no extant relatives. Its extinction can be entirely attributed to relentless hunting and culling.

#3. Mastodon

Charles Robert Knight

A herd of mastodon. Despite their similar appearance, mastodons were somewhat smaller and preferred warmer climes.

Mastodons are commonly confused with mammoths but, although they belonged to the same order, they are quite different animals. Closely related to modern elephants and resembling them significantly, mastodons were also amongst largest and most successful mammalian species during the last ice age. They were found across Eurasia and North America until their extinction approximately 11,000 years ago. Although mastodons were undoubtedly hunted by ancient humans, particularly by the Paleo-Indians in what is now North America, climate change at the end of the last ice age is likely ultimately responsible for their demise.

#4. Mammoth

Charles Robert Knight

A herd of woolly mammoths with the Somme River, northern France, in the background. Note the more hunched back compared to their mastodon cousins.

Mammoths, with their long shaggy coats and huge, curved tusks, are undoubtedly the most famous of the animals of the last ice age. However, contrary to popular belief, they actually only died out around 4,000 years ago. Their closest living relative is the African elephant; with which they share over 99% of their genetic makeup. Some mammoths have been discovered in remarkably good condition, such as Lyuba, the woolly mammoth calf in Chicago’s Natural History Museum. It seems likely that mammoths died out due to a combination of overhunting and climate change. However, some species survived in Wrangel Island right up until 1650 BC.

#5. Smilodon

Charles Robert Knight

An early twentieth century depiction of a smilodon.

The smilodon is the most famous species of sabre-toothed cat, which was a contemporary of the mammoth and mastodon during the last ice age. However, while it is commonly known as the sabre-toothed tiger, it is not actually closely related to any modern feline. Of the three known species, smilodon populator was the largest, weighing up to 880 pounds. At the height of its dominance of the food chain, this ferocious apex predator lived throughout South and North America. Its extinction is largely thought to be an indirect result of climate change and competition with other species.

#6. Moa

Joseph Smit

Standing twice as high as a grown man, the south island giant moa depicted here was the largest of the nine species known.

The moa was a group of nine species of enormous flightless birds that were endemic to New Zealand until their extinction in the early fifteenth century. The biggest of the group was the South Island Giant Moa, standing almost 12 feet high and weighing a staggering 500 pounds. Not only did the incredible size of the moa make it the largest bird to exist during human history; it was also the only modern bird that didn’t have wings. So unique was the creature that it looked more like a feathered dinosaur than any other contemporary creature. Their extinction was a result of overhunting, which also saw the extinction of Haast’s eagle, the moa’s only predator.

#7. Auroch

Charles Hamilton Smith

A contemporary sketch of an auroch or perhaps a cattle/auroch crossbreed, dating from the sixteenth century.

The auroch is the wild ancestor to the domestic cow, and it was one of the most common megafauna across Asia, Europe and North Africa. The last place in the world where Aurochs remained was Jaktorów Forest in Poland, where they were finally declared extinct in 1627 due to unrestricted hunting and encroachment on their natural habitats. The auroch shares almost all its genetic material with modern cattle to such an extent that they could even interbreed. Today, efforts are ongoing to reintroduce the auroch through breeding and rewilding programmes.

#8. Quagga

Jacques-Laurent Agasse

A portrait of a then live specimen, painted in the early nineteenth century.

The quagga was a closely related to the plains zebra that survives to this day. However, while they share the same species and could easily interbreed, they sported quite a different appearance to that of the zebra. Although about the same size, the quagga only had stripes on the back of its neck and head and a brown or white coat on the rest of its body. Quaggas were also hunted to extinction by early Dutch settlers in South Africa, particularly during the 1850s, with the last known wild quagga sited in 1878. The last quagga of all died in 1883 in the Natura Artis Magistra Zoo in Amsterdam.

#9. Doedicurus

Robert Bruce Horsfall

A doedicurus (foreground) and the closely related glyptodont (background), drawn in 1913.

The doedicurus was a type of glyptodont, a subfamily of very large and heavily armoured armadillos. Surviving in South America until around 11,000 years ago, the doedicurus was one of the largest of all ancestors to the modern armadillo. It reached a height of five feet and a length of 13 and weighed up to 5,000 pounds. In addition to its enormous armoured carapace, it had a ferocious club for a tail to fend off any optimistic predator. It is also believed that the tail was used for combat between males competing over a mate. The reason for doedicurus’s extinction remains unclear, though it appears to be entirely natural causes.

#10. Eremotherium

Robert Bruce Horsfall

A megatherium, the slightly larger, elephant-sized cousin of the eremotherium.

A contemporary of doedicurus, and herbivorous ground sloth eremotherium also lived in the Americas until its extinction as a genus around 11,000 years ago. Eremotherium was one of the largest ground sloths ever to exist, reaching lengths of 20 feet and weighing up to three tonnes. Its closest extant relatives are other members of the pilosa order, which includes all anteaters and sloths. A closely related species, as well as a contemporary of the eremotherium, was the megatherium, a ground sloth the size of an elephant. Both species died out between 10 and 11 thousand years ago, likely due to rising human populations in the region.

Thankfully, due to major international wildlife conservation efforts of recent years, the ongoing Holocene extinction event might finally be taking a turn for the better. Nonetheless, the International Union of Conservation of Nature currently still lists around 4600 species of animals and plants as critically endangered, including the mountain gorilla, Javan rhino and Sumatran tiger just to name a few. There is no doubt a great deal more work to do to ensure that many more of the world’s best-loved and most iconic animals aren’t rendered extinct in the coming years.