Woolly Mammoth (Mammuthus primigenius)

Woolly mammoth, a species of mammoth that lived throughout the Pleistocene epoch—also known as the “ice age” (approximately 2.58 million to 11,700 years ago)—became extinct during the Holocene. Its closest living relative is the elephant (Elephas maximus). Knowledge of its physiology and behavior, as an extinct species, has been derived from frozen carcasses found in Siberia and Alaska, as well as from skeletal remains, teeth, gut contents, fecal samples, and prehistoric cave drawings (row stomach cave). Although it began to be recognized in Europe in the 17th century, it was already known in Asia long before, thanks to the discovery of mammoth remains. The species was identified as extinct by Georges Cuvier in 1796.

Physical Characteristics

Although mammoths are often thought of as enormous creatures, the woolly mammoth was roughly the same size as African elephants. Males reached shoulder heights of 2.7 to 3.4 meters and weighed approximately 6 tons. Females stood between 2.6 and 2.9 meters at the shoulder and averaged 4 tons in weight. Newborn calves are estimated to have weighed around 90 kilograms at birth. The woolly mammoth that lived during the last ice age adapted exceptionally well to its cold environment through its thick, woolly coat, which inspired its name. The outermost layer of its fur consisted of long guard hairs, reaching up to 30 centimeters in length on the upper body and up to 90 centimeters on the sides and underside. Although it had far more hair than modern elephants, the structure of its hairs was not significantly different from those of living elephants. The woolly mammoth’s skin contained numerous sebaceous glands that secreted oil onto its hairs, enhancing their insulating properties, water-repellent qualities, and overall gloss.

Diet and Habitat

The presence of food remains at various stages of digestion in the intestines of some woolly mammoth fossils has helped us understand its feeding habits. Its primary food sources were herbaceous plants such as grasses and sedges, along with flowering plants, shrubs, and mosses. It had a herbivorous diet. Like modern elephants, it likely required a broad variety of plant foods to sustain healthy development. An adult woolly mammoth weighing six tons would have needed to consume about 180 kilograms of food daily, which implies it may have spent up to 20 hours per day foraging.

In 2007, a one-month-old female woolly mammoth fossil found on the Yamal Peninsula in Russia provided researchers with valuable insights into the development and diet of juvenile mammoths. The calf, named “Lyuba,” was found to have milk residues in its stomach and feces from other mammoths in its intestines. This deliberate consumption of feces, known as coprophagy, is also observed in modern elephants and rabbits and serves to establish the necessary gut microbiota. It is especially important for herbivores to digest plant material effectively. Isotopic analysis of woolly mammoths from the Yukon region in northern Canada revealed that calves were nursed for at least three years, after which they were gradually weaned onto a herbivorous diet. This nursing period is significantly longer than that of modern elephants. It is believed that this extended lactation evolved as an adaptation to the extreme conditions of the polar regions, helping to protect calves from predators and ensure adequate nutrition during periods of food scarcity and prolonged darkness.

Lifespan and Development

Mammals’ lifespans are generally correlated with their body size. Therefore, the woolly mammoth’s lifespan is estimated to have been similar to that of modern elephants of comparable size—approximately 60 years. Unfused leg bones indicate that, like elephants, woolly mammoths continued to grow and develop after reaching adulthood. Males continued developing until about 40 years of age, while females did so until about 25 years.

The frozen calf known as “Dima” was determined to have been between 6 and 12 months old at death, with a body length of 90 centimeters. At this age, its second set of molars had begun to erupt from below, and its first set was estimated to have been completely worn down by around 18 months. The woolly mammoth underwent a total of six molar replacements during its lifetime. When the final set of molars became worn, the animal could no longer chew its food properly and died of starvation.

How Did the Species Go Extinct?

The majority of woolly mammoth populations disappeared along with much of the Pleistocene megafauna during the late Pleistocene and early Holocene. This extinction event is part of the Quaternary extinction, which began around 40,000 years ago and reached its peak between 14,000 and 11,500 years ago. Scientists hold two main hypotheses regarding the cause of the woolly mammoth’s extinction.

One hypothesis attributes the extinction to human hunting; the other to climate change at the end of the ice age. Regardless of the cause, large mammals with small populations and low reproductive rates are far more vulnerable to environmental pressures, which contributed to their extinction. It is likely that woolly mammoth populations did not vanish simultaneously but declined over thousands of years. Although most populations disappeared between 14,000 and 10,000 years ago, the last known group survived on St. Paul Island in Alaska until about 5,600 years ago. Another theory suggests that the final population persisted on Wrangel Island in the Arctic Ocean until about 4,000 years ago.