The Hairy Elephant
Documenting the history of woolly mammoths in the United States
Introduction
For an animal that existed for 700 thousand years, 12 thousand years since their disappearance in what is now the US is both a short and long time.
If those times were distances, the existence of that animal would span from New York City to Scranton, PA.
And the time since their disappearance from the present-day United States would only span from one end of Central Park in New York City to the other.
The woolly mammoth (Mammuthus primigenius) is arguably the Ice Age animal. Woolly mammoths are top stars in Ice Age movies, and although they're associated with a time of widespread glaciers, tundra, snow, cold, and… ice, they actually lived in places with a fair amount of vegetation.
Woolly environments
A modern example of how woolly mammoth habitat in the present-day US might have appeared.
At the peak of their geographic distribution, woolly mammoths could be found from Spain to Maine. You can zoom in on this map to explore that range further.
At this time in the present-day contiguous United States, woolly spanned west to northern Washington and Montana, south to Kentucky, and east to Maine.
During the peak of the most recent Ice Age, about 20,000 years ago, parts of present-day North America were covered by an ice sheet larger than the one that currently covers Antarctica. No woolly mammoths lived on top of that ice.
And although part of the woolly mammoth's North American range is classified as a former "polar desert," the gray area on this map...
Some of their range was in a "temperate steppe" biome (shown here in orange)—similar to the prairies and grasslands of the central US today.
And a larger part of their range was in a "taiga" coniferous forest (shown here in green), similar to the ones of northern Minnesota and Maine today.
The presence of woolly mammoths in these varied habitats showed that they were not isolated to barren tundras, but rather, lived in a diversity of environments comparable to those today.
What were they like?
Woolly mammoth ivory carving, discovered by French paleontologist Édouard Lartet in 1864.
What was their diet like?
In their Ice Age environments, it is estimated that adult woolly mammoths ate 400 lb. of vegetation per day and might have spent 20 hours per day feeding . These numbers match those of living elephants, like the elephants in this video.
Woolly mammoths along with all other elephants had a very particular way of eating, which can be seen from their teeth.
Instead of a simple "chomping" motion, these animals use a "molar mill" to chew. This is a pattern where the elephant or mammoth bites down, slides its jaw forward, opens its mouth, moves its jaw back, and repeats.
Both woolly mammoths and living elephants have mostly flat teeth with "rumble strip" ridges, which helped them to grind up plants to eat. This photo of a mammoth's lower jaw shows two of these molars.
How did they keep warm?
Woolly mammoths had many adaptations that helped them survive in cold, Ice Age habitats.
The woolly mammoth's fur had two layers : one of long, coarser hairs on top and the other of short, finer hairs on the bottom. The coarser outer hairs were one hundredth to one-fiftieth of an inch (0.25 to 0.5 mm) in diameter, which is about three to six times thicker than human hair. The finer hairs closer to the skin were about one to three inches (2.5 to 8 cm) long but are much more densely packed than the outer hairs.
The skin of woolly mammoths was about as thick as that of living elephants (0.5 to 1 in; 1.25 to 2.5 cm), however, it was underlain by a thick, 3 to 4 in (8 to 10 cm) layer of insulating fat.
Woolly mammoths also had smaller ears and shorter tails than living elephants, which reduced heat loss. In contrast, African savanna elephants (Loxodonta africana) actively wave their large ears to dissipate heat.
Lastly, woolly mammoths had a unique feature on their trunks : a set of small "flaps" on the sides that might have been used to make a trunk tip "mitten", as seen in this figure.
Like living elephants, woolly mammoths probably handled their food with their trunks. Trunks can be very powerful for grabbing whole branches and logs, but their trunk tips can be very dexterous. Woolly mammoths had two "fingers" on their trunks, which were probably used to pick individual leaves and small amounts of grasses. This woolly mammoth painting from Rouffignac Cave in France accurately shows these two "fingers," which can also be seen on woolly mammoths uncovered from permafrost in the Arctic.
How do we know that they were woolly?
Many animals are fossilized in settings that do not preserve their hair. However, woolly mammoths are well known to be woolly because of the abundant samples uncovered from permafrost sites in the Arctic. From these amazingly well-preserved individuals, we have learned that woolly mammoths had a range of hair colors, including a common brown, as well as black, blonde, red, and orange. The permafrost-preserved juvenile woolly mammoth in this photo still has patches of strawberry-blonde fur.
In comparison, this photo of the Yukagir mammoth found in Russia shows its blackish-brown fur.
Do we have evidence of their interactions with each other?
Woolly mammoths were probably very sociable animals too. This panel from Rouffignac Cave (same cave as before) shows two mammoths face-to-face, which might have depicted an altercation or a reunion.
The elephants in this video are a mother, son, and daughter who are reuniting. Elephants will embrace each other in these reunions by "hugging" with their trunks. This may be similar to what the painting in the previous slide was depicting.
What about woolly mammoths and humans in the US?
An artist's interpretation of a woolly mammoth hunt.
Ideas about the Ice Age and human evolution are wrought with images of humans hunting woolly mammoths.
Given humans arrived in what is now the United States at least 20 thousand years ago and woolly mammoths disappeared from the US 12 thousand years ago , 8 thousand years of overlap is plenty of time for hunting.
This figure shows how long large, Ice Age animals and humans overlapped in the US, along with an estimate of where ice sheets were. Note that near present-day Ohio, the overlap is estimated to be 3,000-4,000 years.
Amazingly, this overlap was recent enough that an oral history from the Naskapi Cree of present-day northern Quebec and Labrador called " The Slaying of the Bear " might have been about a woolly mammoth. The original story is known to be very old, and refers to a "huge monster" that made "round, deep tracks in the snow" and had a "long nose..."
And at this site in southeastern Wisconsin, the nearly complete skeletons of two woolly mammoths have been found with stone tools and marks on the bones indicative of butchering. It is unclear whether these mammoths were actively hunted or scavenged though.
How did they become extinct?
Workers at California State University, Fullerton, mount a mammoth skeleton.
In short, the answer is unclear. What is clear is a progression of woolly mammoth range contraction from 40 thousand years ago to their recent extinction four thousand years ago.
To start, this map shows how widespread woolly mammoths were across the northern hemisphere—from Spain to Maine. You can pan and zoom in on this map to explore more closely.
Second, this map shows how reduced their range was from 14 to 10 thousand years ago. Woolly mammoth bones in the United States are not this young, so it is probable that they were no longer there by this time.
By six thousand years ago, woolly mammoths could only be found on a small stretch of the northeastern Russian coast and nearby Wrangel Island .
And six to four thousand years ago, the first writing systems were being developed, Egyptian pyramids were being built, and the last known woolly mammoths passed away on Wrangel Island.
What about climate change after the Ice Age?
In the United States, woolly mammoths disappeared right after a cold snap during a general trend of post-Ice-Age warming. This cold snap is the " Younger Dryas " in this graph of global air temperatures over the past 20 thousand years.
Gradual population decline?
One idea is that woolly mammoths in the United States gradually died out. However, the number of woolly mammoth fossil sites with bones of more than one individual present increased closer to their extinction, suggesting that their populations were growing.
Food web collapse?
An interesting note about where woolly mammoths lived in the United States is that there are not that many carnivore fossils found , despite plenty of herbivore fossils.
Modern large mammalian herbivore populations in Africa tend to be food-limited when fewer carnivores are around, so this might mean that woolly mammoth populations were likewise more strapped for vegetation to eat.
If this were true, this might have made for a less stable food web and "boom-bust" cycles in woolly mammoth populations, like deer have experienced in the absence of North American wolves. The increased number of multi-individual fossil sites might have been a boom, and then their following disappearance might have been their last bust.
Mammoth tipping?
If woolly mammoth populations in the US did get pushed over a "tipping point: how did that happen?
The extinction source is not known to be a singular smoking gun, and might have been a complicated combination of many factors that lined up at just the right wrong time. Although tantalizing, the plausible complexity surrounding this extinction makes it all the more relatable to the complex threats facing living elephants today.
Connections to living elephants
An elephant showing off their long trunk.
To start, Asian elephants, (Elephas maximus) are endangered by overharvesting (especially poaching for ivory) and habitat loss, as well as human-elephant conflict. This conflict is partially caused by climate change as climate change is causing desirable elephant food and habitat loss, leading to more run-ins between Asian elephants and humans.
The African forest elephants (Loxodonta cyclotis) of the Congo are critically endangered by poaching for ivory, habitat loss with expanding agriculture and infrastructure development, and increasingly common droughts.
Lastly, the charismatic African savanna elephants (Loxodonta africana) of eastern and southern Africa are endangered by poaching for ivory, habitat loss through agricultural and infrastructure developments, and again, increasingly common droughts as part of climate change.
What can I do to help conserve modern elephants?
To start, the Worldwide Fund for Nature (WWF) offers internships in conservation:
And the Wildlife Conservation Network (WCN) features many ways to get involved with them to help conserve elephants:
