Giant elephants were more diverse than we had appreciated, it turns out.
A new study published Friday in Science Advances based on ancient mitochondrial DNA from seven mastodons at the far edges of their known ranges reveals three main things:
One is that there wasn’t just one Ice Age mastodon species in North America – there were two: the familiar Mammut americanum and, as of 2019, Mammut pacificus! This diversity had long been suspected paleontologically, but now it’s confirmed genetically. Or maybe there were three. Mastodon of Mexico, who exactly were you?
Haaretz Weekly
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Haaretz Weekly
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Two is that the two mastodon species, americanus and pacificus, had overlapping ranges and likely interbred, according to Emil Karpinski, Sina Baleka, Andrew Boehm, Tim Fedak, Chris Widga and Hendrik Poinar from McMaster University and Harvard.
Three is that mastodons migrated with the movement of glaciers in America. When the ice retreated, they went north. When the ice advanced, northern mastodons died out or went south – their range extended as far as Honduras.
What actually is the difference between mastodons and mammoths? Why are mastodons called Mammut in Latin? And why actually would giant pachyderms roam with the ice?
Elephants harrumph, monkeys triumph
Mastodons had flatter heads than the dome-skulled mammoths, and were smaller and stockier. Mammoths had bulbous heads, were taller and relatively more gracile. Mammoths were grazers and mastodons ate leaves and twigs of shrubs and swampland vegetation, as their teeth clearly show. So, they could exploit different environments.
As for the nomenclature, no, it isn’t that early paleontologists were hopelessly confused.
“The root of Mammut is the same as Mammal, and means ‘breast-tooth,’ researcher Chris Widga helpfully explained in an email to Haaretz. “It refers to the shape of the cusps on the crown. Yes, it is oddly similar to the origins of Mammoth (or Mammut in German).”
In any case, both are now gone, and more recently than you’d think.
Mastodons clung on until about 10,000 years ago and the last mammoth passed away on Wrangel Island in Siberia just as ancient Egypt was rising. Today, elephants still hang on in parts of Africa and Asia – and they’re shrimps compared with some of their extinct cousins, the mammoths.
Proboscideans were a raving success as clades go, originating from small pig-like animals in Africa. “The earliest proboscidean is Eritherium, which lived about 60 million years ago in what is now Morocco,” Widga says. Eritherium was only about 20 centimeters tall and looked like the love child of a pig and a hippo but had the hallmark dentition of the clade.
Next up was Moeritherium in North and West Africa, which had an early trunk and rose to 70 centimeters in height. They were getting bigger. And diversifying. Paleontologists have identified at least three Moeritherium species.
The first proboscideans to leave Africa were the Deinotheres, about 20 million years ago. They had no upper tusks but did have chin tusks curving down towards the ground. And by 25 million years ago, the mastodon and mammoth lineages had already split – back in Africa – and would eventually migrate, too.
We don’t yet know who the common ancestor of mammoths and mastodons was (just like we don’t know which hominin lineage produced Homo sapiens.) “The common ancestor changes between different analyses, but it was probably something like Phiomia, a small (~130 cm at shoulder) elephant-like animal,” Widga notes.
Mastodons arose in Africa but didn’t reach their final forms until migrating through Eurasia to the Americas via the Bering land bridge about 16 or 17 million years ago. Thus, americanum and pacificus are found only in North and Central America.
Mammoths also continued to evolve in Africa and spread to Eurasia about 3 million years ago. They too crossed Beringia to the Americas about 1.5 million years ago.
“Three groups of proboscideans made it to North America: Gomphotheres, Mastodons and Mammoths,” summarizes Widga.
But Emil Karpinski, Widga et al. did not focus on gomphotheres or mammoths – just mastodons. The point is that all sorts of elephant types arose in Africa and spread to Eurasia, time and again – much like early humans. The main difference? One involved pachyderms, the other, clever monkeys – and they did it first.
Hola, quién eres?
The study analyzed mitochondrial DNA from seven mastodons: six Mammut americanum from Nova Scotia and the U.S. East Coast, and one Mammut pacificus from Tualatin, Oregon.
As for the Mexican mastodon, his mitochondria were not part of this study. He might be a very alternative americanum, a pacificus or maybe an unknown species. According to Karpinski, he’s highly diverged. More testing of similar specimens is needed but at present, the indication is that there may have been more mastodon species than we realized.
We’re sending rockets to outer space (never mind that a lot seem to blow up). We can see individual atoms! So why is it still unclear whether there were one, two or three mastodon species in North America?
Because distinguishing between distinct species is not as trivial as one might think. Giraffes – which are huge, unmissable in the landscape, regardless of how well they camouflage in forested environments only had their true diversity recognized in a study published in August 2025, when scientists determined there are four giraffe species in Africa, not three.
So spare a thought for paleontologists categorizing extinct animals based only on fossil bones, especially when colleagues can’t even agree on which animal they came from. But in recent years, techniques to extract and analyze ancient DNA have changed the game – not only in studying human and giraffe evolution, but also on the great elephant migrations across the Americas.
Elephant for dinner
So mastodons spread all over North America, glaciation permitting, from Alaska and Canada as far south as Honduras. Their specific range at any given time depended on the climate. In any case, they had at least some geographical overlap, and may also have interbred, just as Homo sapiens did with Neanderthals and Denisovans. And apparently other hominins as well – it’s all about opportunity, isn’t it?
Speaking of, a relatively new theory of human evolution from Ran Barkai and his team from the Department of Archaeology and Ancient Near Eastern Cultures at Tel Aviv University ties human evolution to the elephant. Long and bloody story short: about 2 million years ago, our ancestors became intensely carnivorous and targeted the biggest animals, which had the thickest layers of fat. Humans can’t have more than 35% to 50% of their nutrition based on protein alone without getting nitrogen poisoning. So we evolved to crave fat (admit it – nobody dreams of roasting carrots over the open fire.)
As hominins exited Africa, they hunted megafauna – especially elephants – everywhere they went – across Africa, the Levant, Eurasia and eventually, the Americas.
In previous work the team detected evidence for at least two phases of migration into the extreme north (Beringia), Alaska and Canada, when glaciers were melting. Now, according to Karpinski, the mitochondrial DNA of the six americanus they tested indicate three or possibly four migrations on the east coast.
Bottom line: Elephants affected our evolution and we affected their extirpation, but the degree to which we affected the final mastodon extinction remains unknown. Still, there are clues.
“Gomphotheres and Mastodons both arrived around the same time, 17 million years ago. Mammoths arrived much later, about 1.5 million years ago,” Widga sums up. “Both mastodons and mammoths were very common at the end of the Pleistocene and overlap with humans. Gomphotheres were also still around at that time, but seem to be much rarer in North America… Although there are only a handful of sites, human tools have been found with all three groups.”
Oh dear. That whiff of human culpability again.
But let’s be fair: mastodons were already branching out long before Homo sapiens showed up, as Karpinski points out. Most species were extinct before we even began to evolve.