With more than 41,000 species currently under threat of extinction worldwide, it might not be long before endangered loggerhead turtles, red wolves and manatees disappear from the US for good. We have lost incredible creatures before, from the hordes of prehistoric megafauna (giant mammals) that met their maker some 10,000 years ago to more recent losses brought about by humans. Here, we take a look at the animals that once lived on the land and in the waters of the modern United States of America, now gone forever...

Long before Game of Thrones made dire wolves cool, these ancient canines – whose name means dreadful – prowled the plains of the Americas. Larger than today’s grey wolf and the largest ancestral canines that ever lived, they existed between 2.6 million and 11,700 years ago, before dying out at the end of the last Ice Age. Dire wolf skeletons have been found in Florida, the Mississippi River valley and La Brea Tar Pits in California, where thousands of them were discovered among the fossilised remains of sabre-toothed cats, showing the two formidable predators would have likely battled over territory and prey.

When we think of bears, speed isn’t usually the first thing that comes to mind. But the giant short-faced bear is said to be the fastest bear that ever roamed the Earth, capable of reaching 40 miles per hour (64km/h) despite weighing 1,500 pounds (680kg). It lived in Minnesota, Alaska and in the open country to the west of the Mississippi, hunting large herbivores such as bison, deer and ground sloths. When changes in habitat led to the population decline of its prey during the last Ice Age (between 110,000 and 12,000 years ago), the giant short-faced bear soon disappeared.

Dating back to the Pleistocene and early Holocene epochs (a time known as the Quaternary), fossils of these elephantine beasts have been found across America’s Midwest, New England and Alaska. Characterised as having long, furry coats and intimidating tusks, woolly mammoths were a victim of habitat loss and global warming in the aftermath of the last Ice Age. In 2017, new research revealed that the very last woollies could have died out as a result of complications from a DNA mutation. This could have caused olfactory issues and changes in the animals' urine, affecting their success in finding mates.

The Columbian mammoth, though not as big in terms of fame, actually grew to be much larger than the woolly mammoth. Standing at over 14 feet (4m) tall and around 20,000 pounds (9,072kg) in weight, with tusks that could extend up to 16 feet (5m) long, they were titanic creatures. Living in what is now Texas until the end of the Ice Age, they had much less hair than their woolly relatives due to the warmer climate. At the Waco Mammoth National Monument, palaeontologists have unearthed 24 Columbian mammoths since 1978.

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Evidence of this species of mammoth has only ever been found on the California Channel Islands, after a herd of Columbian mammoths swam across from the mainland to the islands (then mostly one island known as Santarosae) and evolved to a more diminutive size. Believed to have been around half the height and just a tenth of the weight of the Columbian mammoth, pygmy mammoths were a product of natural selection; as food became harder to source due to climatic changes on Santarosae, smaller mammoths had better survival odds. They were wiped out some 10,000 years ago in a wider extinction of megafauna.

This distant cousin of mammoths and modern elephants (a family known as proboscideans) went extinct with other ancient North American proboscideans around 11,000 years ago. Mastodon fossils have been found in areas formerly covered by cool woodlands, reaching from Alaska all the way to Mexico. A chunk of mastodon tusk unearthed at the Hagerman Fossil Beds National Monument in Idaho showed it to have growth rings inside, not unlike those of a tree trunk.

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Sometimes called the elk-moose, this enormous prehistoric deer weighed around 1,500 pounds (680kg) and stood at 12 feet (3.7m) tall. Its majestic palmate antlers were more complex than those of today’s moose, while it had a muzzle closer to a typical deer and a more elk-like frame. Remains of the stag-moose were first found at Big Bone Lick in Kentucky at the beginning of the 19th century, while other evidence has since been discovered in states such as New Jersey, Ohio, Indiana, Iowa and Wisconsin. Factors like hunting, habitat loss and competition are believed to have contributed to the animal’s demise.

It’s hard to imagine lions living in America as they do today in Africa’s grasslands and national parks. But until the end of the most recent Ice Age, they did exactly that – stalking the savannas of what is now the United States alongside other apex predators, such as the dire wolf and sabre-toothed cat. The American lion was around 25% larger than the modern African lion and would have hunted camels, bison, ground sloths and young mammoths before its extinction, which was brought about by early humans, climate change and the loss of its usual prey.

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The shrub-ox was one of the earliest bovids (hoofed mammals with simple horns) to arrive on the North American continent, crossing into the territory during the early Pleistocene. It would have been sized somewhere between today’s American bison and the muskox, weighing in at around 1,340 pounds (608kg). Traces of its presence have been found predominantly in the southwestern United States, where scientists have been able to deduce the animal’s diet of trees and shrubs from deposits of preserved dung. The shrub-ox was another victim of the Quaternary extinction.

Named after Vero Beach in Florida where remains of the species were first discovered, this prehistoric tapir would have borne a considerable resemblance to today's tapirs, possessing a tiny trunk and characterful underbite. Until its disappearance at the turn of the Holocene (along with other megafauna), it lived in temperate and subtropical forests across much of southeastern America, from Florida, Georgia and the Carolinas to as far west as Texas and as far north as Pennsylvania. Pictured here are the jawbones of a vero tapir, on display at the Tellus Science Museum in Cartersville, Georgia.

Believed to be an ancestor of the living American bison, this primeval beast could have grown to be 25% larger than any bison roaming the United States today, tipping the scales at around 3,500 pounds (1,588kg). Aside from mass, dominant height and more elongated horns set the ancient bison apart from extant bison, but otherwise they were fairly similar – living in herds in open habitats, like grasslands. Fossils have been found in places such as Nevada’s Tule Springs Fossil Beds, with the oldest known ancient bison remains in North America dating back as many as 240,000 years.

In ancient times, these super-sized, buck-toothed rodents roamed from Florida to Alaska. The giant beaver could weigh up to 276 pounds (125kg) and grow to over seven feet (2m) from nose to tail (which was skinny like a rat’s – not paddle-like as per today). It dwarfed modern beavers considerably and closer matched the bulk of a black bear, while its signature incisor teeth were much larger too. But the giant beaver was subsequently outlived by the modern beaver, disappearing along with other megafauna around 10,000 years ago.

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The camelops was the last-surviving species of large North American camel prior to its extinction at the end of the most recent Ice Age. Having evolved from the protylopus genus of camel, which was rabbit-sized, the camelops – sometimes Western camel or American camel – migrated across the land bridge of Beringia (now the Bering Strait) before its disappearance in North America, ensuring its legacy lived on. Camelops fossils have been unearthed in Waco, Texas, alongside the remains of Columbian mammoths, with the animal known to have inhabited lands west of the Mississippi River from Alaska to Mexico.

Few prehistoric creatures terrify and fascinate like the sabre-toothed cat. Shorter but nearly twice as heavy as a modern lion, its muscular build and scythe-like canines helped effectively ambush and violently kill prey. From southern Canada through the United States and down to Peru, the formidable predator hunted camels, bison, ground sloths, even juvenile mammoths and mastodons. Sabre-toothed cat footprints have been preserved at White Sands National Park in New Mexico, while skeletons entombed in California’s La Brea Tar Pits (a source of crude oil used by Native Americans) suggest many animals perished here after becoming mired in the viscous substance.

A kind of prehistoric pig, not too dissimilar to a living wild boar or warthog, the long-nosed peccary inhabited the forests and parklands of the American Midwest, as well as Florida and Appalachia. The main difference between peccaries and modern pigs is that their tusks grew downwards, as opposed to upwards. While the long-nosed peccary succumbed to the last Ice Age, its relative the collared peccary remains in the US today, ranging from Arizona to Texas.

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The Northern glyptodont was one of a number of glyptodon species that walked the planet during the Ice Age. It was a large herbivore with an armoured scaly shell, like the extant armadillo but substantially bigger, that grazed the open pastures of North America. Thanks to their natural chain mail, glyptodonts didn’t make easy prey, despite living in a time of accomplished killers like the sabre-toothed cat and dire wolf. But this shield could not protect them from the perfect storm of human interference, habitat loss and climate change that came with the Quaternary, and they were ultimately lost to history.

Far from the megafauna that dominated during the Ice Age, the dwarf pronghorn was a little slip of an antelope-like creature that weighed only 22 pounds (10kg) and stood at less than two feet (60cm) tall. Unsurprisingly, despite being spritely, it was popular prey for many animals. Dwarf pronghorn have been uncovered among the remains of several other Pleistocene mammals in La Brea Tar Pits, with their fossils also found in Nebraska, Kansas, New Mexico and on the Texas coast.

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Also known as Harlan’s muskox or the helmeted muskox, the woodland muskox was seemingly more agile than the tundra muskox that exists today, with longer legs and a lighter coat. It shared the same ecosystem – and existential collapse – as the stag-moose and giant beaver, ranging from southern Canada and Alaska to Arkansas and the Midwest to New Jersey. While the woodland muskox disappeared with the terminal Pleistocene, the genetically different modern muskox is one of the oldest mammals to still roam the Earth.

Closely related to modern zebras, the native ancient horse was one of the last-surviving prehistoric equids that galloped across North America from around two million years to 10,000 years ago. After the horses went extinct on the continent, ancestors of those that crossed the Beringia into what became Europe made an unexpected comeback around the 16th century with Spanish conquistadors, who used them as their steeds. Palaeontologists have found ancient horse remains across California and Texas, as well as Central and South America.

This Ice Age scavenger – another casualty of the Quaternary extinction event – behaved similarly to today’s condors and vultures, soaring over great distances in search of small animals to swoop upon and iron-rich carcasses to tear apart with its knife-sharp beak. The fossil record tells us the teratorn lived and hunted in what are today's states of California, Oregon, Nevada, Arizona and Florida. With a wingspan of 11 to 12 feet (around 3m), the prehistoric bird of prey was about a third larger than living condors.

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A more petite, shorter-haired cousin of the modern species, Harrington’s mountain goat was known to inhabit the southwestern United States before dying out at the end of the last Ice Age. Clues deduced from its preserved dung found in caves around the Grand Canyon suggest the animal relied on grasses and trees for food, the availability of which could have been affected by the Quaternary’s changing climate. This, exacerbated by population loss as a result of human hunting, is what scientists believe caused the goat to go extinct.

Ground sloths originated in South America around 35 million years ago, but started making their way north around eight million years ago. Living in the western US until the climax of the most recent Ice Age, they could grow up to 10 times the size of the sloths we know today, reaching up to four tonnes in weight – the same as a male elephant. When standing on its hind legs to forage in trees, this gargantuan herbivore was 12 feet (3.5m) tall. One species of ground sloth, the Megalonyx jeffersonii, is named after the third US president Thomas Jefferson, who is credited with its discovery.

Until relatively recently, this subspecies of elk roamed northeast America, where the mating calls of its bulls would reverberate through the hills and valleys of New England and beyond. With dark manes and cream-coloured fur, the eastern elk was also called ‘wapiti’, meaning white rump in the language of the Indigenous Shawnee peoples. As more European settlers arrived in the US during the 19th century, overhunting became an issue for the eastern elk. The last of its kind was shot in Pennsylvania in 1877, with the United States Fish and Wildlife Service officially declaring it extinct three years later.

Like the eastern elk, the sea mink was hunted to extinction in the late 1800s. Highly sought-after for its pelt, due to being larger than the American mink, the sea mink lived around the east coast of America and maritime Canada. Little palaeontological evidence remains of this elusive creature – its only known traces are bone fragments found among other debris in Native American shell middens, while the majority of details pieced together about its external appearance come from speculation and the word of fur traders and Indigenous Americans.

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Again, not much is known for certain about the Labrador duck, which had disappeared entirely without fanfare from America’s Atlantic coast by the turn of the 20th century. The zoologist and conservationist John C. Phillips theorised in 1926 that humans settling around its coastal habitat could have interfered with the duck’s supply of shellfish to a catastrophic extent, but it’s impossible to know for sure whether that led to its extinction. Very few specimens of Labrador duck exist today to reveal the truth; it was just as rare and mysterious in life as in death.

This lost subspecies of grey wolf lived in southern Alaska until 1925 and was the largest wolf in North America before humans drove it to extinction. The Klondike Gold Rush in 1895 signalled an influx of miners to the region, who brought with them a bloodlust motivated by the value of wolfskins and a fear of rabies. Within three decades, the Kenai Peninsula wolf had been eradicated. It joins the Texas wolf, the Florida black wolf, the Cascade Mountains wolf and more on the list of wolves recently classified as extinct in the United States.

The loss of Steller’s sea cow has the dubious accolade of being history’s first extinction of a marine mammal engineered by human hands. Sea cows were huge creatures – bigger than many modern whales – that swam in the subarctic waters of the northern Pacific. Within 27 years of them being discovered by science in 1741, Steller’s sea cows had been killed outright to serve as meat for seal hunters on long journeys and material for the international fur trade. The sea cow’s closest living relatives are manatees and dugongs, whose futures are also threatened by human activity.

While grey whales still exist today, their Atlantic population succumbed to the commercial whaling industry in the 18th century and they were declared extinct. But, in a bittersweet twist of fate, could climate change mean grey whales might return to the Atlantic? A confirmed sighting of a Pacific grey whale in the Atlantic in 2013 suggests that, as the climate crisis continues to warm the world’s oceans and blur the boundaries between them, it’s plausible that the Atlantic could soon be repopulated with grey whales once again.

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