Division by subtraction: Extinction of large mammal species likely drove survivors apart

SEPTEMBER 19, 2019

by University of Nebraska-Lincoln

When a series of large mammal species began going extinct roughly 12,000 years ago, many surviving species began going their separate ways, says new research led by Macquarie University and the University of Nebraska-Lincoln.

Published Sept. 20 in the journal Science, the study analyzed distributions of mammal fossils across North America following the last ice age, after the retreat of massive glaciers that had encroached south to the modern-day United States. The aftermath saw the disappearance of many famously large mammal species: mammoths, mastodons, saber-toothed cats, dire wolves and ground sloths, among others.

Surviving mammal species often responded by distancing themselves from their neighbors, the study found, potentially reducing how often they interacted as predators and prey, territorial competitors or scavengers.

The ecological repercussions of the extinctions are likely still echoing today and could preview the effects of future extinctions, said study co-author Kate Lyons.

"For 300 million years, the (cohabitation) pattern of plants and animals looked one way—and then it changed in the last 10,000 years," said Lyons, assistant professor of biological sciences at Nebraska. "This paper addresses how that happened in mammal communities.

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