The woolly mammoth was not a separate kind of beast. It belonged to the elephant family and was more closely related to today’s Asian elephant than to the African elephant.1PubMed. Multiplex amplification of the mammoth mitochondrial genome and the evolution of Elephantidae The differences that mattered most were adjustments for life on freezing northern grasslands, reaching from its coat all the way down to its blood chemistry. Many of those cold-weather features were already in place long before the woolly mammoth appeared, so the animal was the end of a long run of mammoths adapting to the north.2PubMed Central. Million-year-old DNA sheds light on the genomic history of mammoths
How Mammoths and Elephants Are Related
Mammoths, African elephants and Asian elephants are three branches of one family, all descended from a shared ancestor in Africa. Of the living elephants, the Asian elephant shares the most recent common ancestor with the mammoth.3PubMed. Multiplex amplification of the mammoth mitochondrial genome and the evolution of Elephantidae That is why the Asian elephant is the usual stand-in when scientists try to picture how a living mammoth’s body worked.
Mammoths did not evolve from Asian elephants, and Asian elephants did not descend from mammoths. Both descend from a common ancestor that was neither.
The woolly mammoth also came late in a long line. Earlier mammoth species lived in Europe and Asia more than a million years ago, and the woolly mammoth descended from them.4PubMed Central. Million-year-old DNA sheds light on the genomic history of mammoths Woolly mammoths then survived until about 4,000 years ago on Wrangel Island, an Arctic island where a small population lasted long after those on the mainland were gone, after the Egyptian pyramids were built.
Mammoths are often confused with mastodons, because both get called “prehistoric elephants.” Mastodons are a separate, more distant group, not a type of mammoth. They had cone-shaped teeth suited to browsing leaves and twigs, while mammoths had flat, ridged teeth more like those of living elephants.
Coat, Ears, Tail and Feet
Woolly mammoths had long, thick hair in three layers, while living elephants have only sparse bristles.5Contemporary Problems of Ecology. Adaptation of the woolly mammoth Mammuthus primigenius (Blumenbach, 1799) to habitat conditions in the glacial period The coarsest outer hairs had many hollow-looking channels running along each strand, more than are seen in living mammals.6Quaternary Science Reviews. Megafaunal split ends: microscopical characterisation of structure and function in extinct woolly mammoth and woolly rhino The fine underhair close to the skin had no such channels.7Quaternary Science Reviews. Megafaunal split ends: microscopical characterisation of structure and function in extinct woolly mammoth and woolly rhino So the coat likely combined tough, insulating outer hairs with a soft, dense layer underneath.
Dense underhair traps still air near the skin, and the long outer hairs shed snow and wind so the warm layer stays in place. Living elephants face the opposite problem, shedding heat, so bare skin suits them.
Frozen carcasses show hair that can look reddish-brown, though the colour may have faded over time. Outer hairs could grow long enough to hang down like a skirt.
The rest of the body shrank or padded the parts that lose heat:
- Ears: small, where elephants have large ones that radiate heat.8Contemporary Problems of Ecology. Adaptation of the woolly mammoth Mammuthus primigenius (Blumenbach, 1799) to habitat conditions in the glacial period
- Tail: short, exposing less skin to the cold.9Contemporary Problems of Ecology. Adaptation of the woolly mammoth Mammuthus primigenius (Blumenbach, 1799) to habitat conditions in the glacial period
- Back: a fatty hump that stored energy.10Contemporary Problems of Ecology. Adaptation of the woolly mammoth Mammuthus primigenius (Blumenbach, 1799) to habitat conditions in the glacial period
- Trunk tip: a hood-like flap, likely shielding it from frost.11Contemporary Problems of Ecology. Adaptation of the woolly mammoth Mammuthus primigenius (Blumenbach, 1799) to habitat conditions in the glacial period
- Feet: wide soles, spreading weight on snow and frozen ground.12Contemporary Problems of Ecology. Adaptation of the woolly mammoth Mammuthus primigenius (Blumenbach, 1799) to habitat conditions in the glacial period
The hump was a reserve of fat the animal could draw on when food was scarce. Northern winters left little to eat, so a body that could bank energy in summer had an advantage.
Woolly mammoths were roughly the size of an African elephant, not giants beyond it. Their sloping back and high domed head gave them a different silhouette.
Cold-Ready Blood and Genes
Red blood cells carry hemoglobin, a protein that picks up oxygen in the lungs and drops it off in tissues around the body. Normally it holds onto oxygen more tightly as it gets colder.13PubMed. Substitutions in woolly mammoth hemoglobin confer biochemical properties adaptive for cold tolerance The drop-off is what suffers: in the cold, hemoglobin clings to its oxygen instead of handing it over. Legs and trunk are far from the heart and lose heat to the air, so cold body parts like these would struggle to get oxygen delivered.
Mammoth hemoglobin had changes that let it release oxygen in the cold while wasting less body heat.14PubMed. Substitutions in woolly mammoth hemoglobin confer biochemical properties adaptive for cold tolerance Lab comparisons show it reacts to body chemicals differently from Asian elephant hemoglobin, even though the two are otherwise similar.15PubMed Central. A Biochemical-Biophysical Study of Hemoglobins from Woolly Mammoth, Asian Elephant, and Humans Scientists read the hemoglobin gene from preserved mammoth DNA, make the protein in the lab and measure how it holds oxygen.
Genes changed only in mammoths are linked to hair and skin, fat storage, sensing temperature, and body clocks.16PubMed. Elephantid Genomes Reveal the Molecular Bases of Woolly Mammoth Adaptations to the Arctic The mammoth’s genes also showed reduced sensitivity to cold and a special way of handling fat.17Contemporary Problems of Ecology. Adaptation of the woolly mammoth Mammuthus primigenius (Blumenbach, 1799) to habitat conditions in the glacial period Many of these changes, including ones for the immune system, were already present when the woolly mammoth first appeared.18PubMed. Genomics of adaptive evolution in the woolly mammoth
Cold sensing works differently from insulation. Living animals feel cold through nerve sensors that trigger discomfort. A less sensitive sensor would let a mammoth stand in freezing air without distress, changing what the body feels rather than how warm it stays.
Body-clock genes matter in the far north, where summers have near-constant daylight and winters near-constant dark. Living elephants are tuned to tropical days of steady length.
Teeth, Tusks and Diet
Over time, mammoth molars developed thinner enamel arranged in more numerous ridges.19PubMed. Paleotribological models using preserved fossil tissue properties reveal functional significance of Eurasian mammoth dental evolution This didn’t make the teeth wear down any slower overall, because more ridges with thinner enamel kept the total chewing surface of enamel about the same.20PubMed. Paleotribological models using preserved fossil tissue properties reveal functional significance of Eurasian mammoth dental evolution Instead, the worn tooth formed a flat, file-like surface with many sharp edges that shredded fibrous grass.21PubMed. Paleotribological models using preserved fossil tissue properties reveal functional significance of Eurasian mammoth dental evolution That let mammoths live on the tough, low-nutrition grasses of the cold steppe.
Tusks differed too. Woolly mammoth tusks curved strongly upward and inward, often in a spiral, while African elephant tusks are straighter and point forward. The curve may have helped sweep snow off grass. Mammoths of both sexes had tusks, unlike female Asian elephants, which often have small ones or none.
Both mammoth and elephant ivory show a cross-hatched pattern visible to the eye, made by tiny channels in the tusk.22PubMed Central. Mammoth ivory was the most suitable osseous raw material for the production of Late Pleistocene big game projectile points The angles of the crossing lines are above 90 degrees in African elephant ivory and slightly below 90 in woolly mammoth ivory.23PubMed Central. Mammoth ivory was the most suitable osseous raw material for the production of Late Pleistocene big game projectile points Experts can use those angles as one test, alongside other evidence, to tell fossil mammoth ivory from modern elephant ivory.
The ivory also behaves differently under force. African elephant ivory is less stiff but tougher to break, and harder than mammoth ivory in one direction of force.24PubMed Central. Mammoth ivory was the most suitable osseous raw material for the production of Late Pleistocene big game projectile points Thawing permafrost now exposes mammoth ivory that is traded legally in some places, which is why telling it apart from elephant ivory matters.
Not every mammoth ate the same way. The gut bacteria of one frozen mammoth closely matched those of the African forest elephant, so that animal likely lived in a marshy, wooded area rather than open grassland.25PubMed Central. Meta-proteomic analysis of the Shandrin mammoth by EVA technology and high-resolution mass spectrometry: what is its gut microbiota telling us?
Behaviour and Life Cycle
Musth is a yearly period when adult male elephants surge in testosterone, become aggressive and compete for mates.26Nature. Testosterone histories from tusks reveal woolly mammoth musth episodes Tusks grow in layers, a little like tree rings, and each layer forms at a different age. Chemical traces in a layer reflect the hormones in the body when it formed, so the layers keep a record of hormone levels over the animal’s life.27Nature. Testosterone histories from tusks reveal woolly mammoth musth episodes Reading them in order reveals the years when testosterone surged. Testosterone peaks in a male mammoth’s tusk show that mammoths experienced musth too.28Nature. Testosterone histories from tusks reveal woolly mammoth musth episodes
Much else is borrowed from elephants. Low-pitched rumbling calls, brain features and breeding are mostly inferred from living elephants rather than measured in mammoths.29Trends in Ecology & Evolution. Understanding proboscidean evolution: a formidable task Elephants communicate with very low sounds that travel kilometres. Mammoths likely did too, but sounds don’t fossilise, so this remains a reasonable guess.
The same goes for herds. Living elephants form female-led family groups while adult males roam. Mammoth fossils of groups of females and young fit that pattern, and the musth evidence supports the idea that males competed as elephants do.
Why Mammoths Died Out and Elephants Didn’t
Mammoth numbers fell as the Ice Age ended and their cold grasslands shrank.30PubMed. Process-explicit models reveal pathway to extinction for woolly mammoth using pattern-oriented validation Climate alone can’t explain the timing, though. Humans likely sped up the decline by many thousands of years.31PubMed. Process-explicit models reveal pathway to extinction for woolly mammoth using pattern-oriented validation Human pressure on mammoths began long before the last Ice Age ended, and small groups hung on in Arctic refuges until a few thousand years ago.32PubMed. Process-explicit models reveal pathway to extinction for woolly mammoth using pattern-oriented validation
The mammoth steppe was a vast cold, dry grassland across northern Asia, Europe and North America. Today much of it is wet tundra or forest, which removed the main food source mammoths depended on. Hunting added pressure on top of shrinking habitat, and slow-breeding animals recover poorly from extra losses.
Elephants live in warm regions that didn’t vanish when the Ice Age ended, so their habitat wasn’t squeezed the way the mammoth steppe was. They now face their own threats from poaching and habitat loss.
Mammoths also shaped their landscape. Large grazers kept the far north as grassland rather than moss and shrub tundra.33PubMed Central. Pleistocene Arctic megafaunal ecological engineering as a natural climate solution? For that reason, some scientists propose bringing back big grazers to keep grassland that could slow permafrost thaw and lock up carbon.34PubMed Central. Pleistocene Arctic megafaunal ecological engineering as a natural climate solution?
Could Scientists Bring Back a Mammoth
Researchers have edited up to seven genes at once in mice to mimic mammoth hair and fat traits, and the mice grew curly, textured, golden-brown coats.35bioRxiv. Multiplex-edited mice recapitulate woolly mammoth hair phenotypes The work shows individual traits can be copied, not that a whole mammoth can be recreated.
Because the Asian elephant is the mammoth’s nearest relative, any mammoth-like animal would be an edited Asian elephant.36PubMed. Multiplex amplification of the mammoth mitochondrial genome and the evolution of Elephantidae The result would be a cold-adapted elephant carrying some mammoth genes rather than a true mammoth.
The hurdles are large. Elephant pregnancies last about 22 months, which slows any project, and Asian elephants are endangered, raising concerns about using them. Hair alone isn’t enough, since blood, fat and cold sensing would also need changing. Raising a social animal without a herd raises welfare questions too.
Some hope cold-hardy elephants could graze the Arctic and help keep grassland. Others see the work as a way to develop tools for protecting endangered elephants. Critics argue the money is better spent saving living elephants.