What were rats like during the Ice Age? - briefly
During the Pleistocene, rats were small, robust murids with dense fur, feeding on seeds, insects, and carrion, and they occupied tundra and boreal forest habitats. Fossil records indicate their anatomy was largely similar to that of present‑day rats, showing only minor adaptations to colder climates.
What were rats like during the Ice Age? - in detail
During the Pleistocene, several rat species inhabited cold‑steppe and tundra environments across Eurasia and North America. The most common representatives were members of the genus Rattus and the closely related genus Cricetomys, together with extinct forms such as Rattus exulans subspecies and the giant Rattus longicaudatus.
Morphologically, these rodents displayed robust bodies, dense fur, and shortened extremities that reduced heat loss. Skeletal remains indicate a slightly larger skull and stronger jaw muscles compared with modern Rattus norvegicus, suggesting a diet that included tougher plant material and larger invertebrates. Dental wear patterns reveal frequent consumption of fibrous grasses, seeds, and occasional carrion.
Adaptations to glacial conditions included:
- Seasonal fur thickening, inferred from isotopic analysis of hair keratin.
- Burrowing behavior that provided insulation from subzero winds.
- Seasonal migration to milder microhabitats, such as river valleys and coastal zones.
Fossil sites in Siberia, the Altai Mountains, and the Bering Land Bridge contain abundant rat teeth and vertebrae, confirming a wide geographical range. Radiocarbon dating places most specimens between 115,000 and 11,700 years ago, overlapping the last glacial maximum.
Ecologically, these rodents occupied a niche as opportunistic omnivores, competing with lemmings, voles, and early hares. Their presence in cave deposits alongside megafauna indicates scavenging on carcasses left by predators. Predation pressure from wolves, bears, and birds of prey likely favored rapid breeding cycles; growth rings in tooth enamel suggest a gestation period of roughly 20 days, similar to contemporary species.
Comparisons with present‑day rats highlight evolutionary continuity: modern Rattus retains the general body plan, but has reduced fur density and a narrower dietary spectrum, reflecting the warmer climates of the Holocene. The Pleistocene forms, however, illustrate a lineage capable of surviving extreme cold through physiological and behavioral modifications that are absent in most current urban rat populations.