Cancer on the Brink of Ice Age Extinction: Why Did Mammoths and Cave Bears Become Ill?
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Day 6 (History of Cancer in 365 Days Series)
When discussing cancer history, we usually focus on one individual, one patient’s story. Sometimes, however, fossils reveal more than a personal tragedy: they tell us about a health crisis affecting an entire species.
Our final stop before written history and human civilization is the Ice Age (Pleistocene Epoch). Around 20,000 years ago, while glaciers covered the Northern Hemisphere, giants such as Woolly Mammoths and Cave Bears reigned.
But these giants did not spend their final days fighting only human spears, as films suggest; they also fought enemies “within”—serious tumors and genetic deterioration. Today, we examine evidence showing extinction as more than a moment of death: a genetic and environmental collapse.
The “Sick Giants” Hypothesis: What the Bones Say
When paleontologist Sergey Leshchinskiy of Russia’s Tomsk State University examined “mammoth graveyards” in Siberia, Europe and northern Russia, he found a shocking picture. Nearly half of the more than 23,000 bones examined (40-50%) showed signs of serious disease.
The bones of these giants, which should have been nature’s most powerful tanks, had deteriorated, deformed, become fragile and filled with tumors. Here are the critical diseases scientists identified:
1. A Tumor in the Bones: Osteoblastoma
The Spadzista site in Krakow, Poland, contains one of the world’s largest accumulations of mammoth bones. A mammoth vertebra (thoracic vertebra) recovered there contained a rare tumor called Osteoblastoma in the bone.
- What Is It? A benign tumor involving uncontrolled proliferation of bone-forming cells. But “benign” does not mean harmless.
- Its Effect: By pressing on the spinal cord, this tumor probably caused unbearable pain and restricted the animal’s movements. In the wild, inability to move is a death sentence.
2. The Signature of Genetic Collapse: A “Cervical Rib”
Perhaps a finding more frightening than tumors was hidden in mammoths’ necks. Almost all mammals, from giraffes to mice, have a fixed number of cervical vertebrae: 7. This is a tightly conserved rule of evolution. Yet mammoth fossils from the Netherlands and the North Sea showed an extra rib forming at the 7th cervical vertebra (Cervical Rib).
- Why Does It Matter? This anomaly is more than an extra piece of bone. It signals disruption of the genome’s “Hox genes,” which regulate the body plan. In modern medicine, this condition is often associated with stillbirths and childhood cancers.
- Meaning: As the mammoth population declined, survivors were forced to breed among themselves (Inbreeding). This genetic bottleneck increased susceptibility to cancer and developmental disorders.
3. Mineral Starvation (Osteodystrophy)
According to Leshchinskiy’s theory, changing climate acidified the soil and reduced minerals in plants. Mammoths could not obtain enough calcium and phosphorus to sustain their enormous skeletons. This “mineral starvation” caused bone softening (Osteomalacia) and fractures. Mammoths died out not only from hunger, but also because their bones could no longer support their bodies.
- Leshchinskiy SV. Paleoecological investigation of mammoth remains from the Krakow Spadzista Street (B) site. Quaternary International. 2012;276:155-169.
- Reumer JW, et al. Extraordinary incidence of cervical ribs indicates vulnerable condition in Late Pleistocene mammoths. PeerJ. 2014;2:e318.
- Leshchinskiy SV. Enzootic diseases and extinction of mammoths as a reflection of deep geochemical changes in ecosystems of Northern Eurasia. Archaeological and Anthropological Sciences. 2015.
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