Ancient DNA Analysis Changes Everything

A groundbreaking DNA analysis of ancient mastodons has unveiled a stunning truth: these Ice Age behemoths migrated across North America in response to climate change, showcasing a surprisingly complex evolutionary lineage.

A New Perspective on Evolution

Published in *Science Advances*, a collaborative study by researchers from McMaster University and Harvard University reshapes our understanding of mastodon history. By analyzing fossilized teeth, tusks, and bones that date back hundreds of thousands of years, experts reconstructed mitochondrial genomes from these ancient giants, revealing a level of genetic diversity previously thought impossible.

From Many to One: The Mastodon Story

Initial classifications divided mastodons into various species before consolidating them under the name *Mammut americanum*. Recent findings suggest that there may actually be at least two distinct species: the American mastodon and the newly identified Pacific mastodon (*M. pacificus*). This debate continues, sparking intrigue within the scientific community.

Alberta: The Mastodon Meeting Ground

Remarkably, Alberta appears to have been a congregation point for both Pacific and American mastodons, leading scientists to consider it a hotspot for potential interbreeding. The genetic analysis highlights two unique clades in Eastern specimens, each representing distinct populations separated by time—underscoring the regions' historical significance.

Climate Cycles Drive Migration Patterns

The research indicates that the East Coast mastodons had a bountiful diversity, arriving in waves at least three times, guided by fluctuating climates. As temperatures warmed, glaciers melted, allowing these creatures to expand their territories northward. Conversely, during colder periods, many were driven south or faced extinction.

Mexico's Genetic Mystery

Intriguingly, researchers identified a unique lineage of mastodons in Mexico, hinting at the possibility of it being an entirely new species or a deeper branch of the Pacific mastodon.

Living Among Giants

At their peak, mastodons were among the largest land animals on Earth, ranging from Beringia (now Alaska and Yukon) to Nova Scotia and as far south as Central Mexico. Unlike their woolly mammoth cousins that preferred open grasslands and tundra, mastodons thrived in swampy environments, browsing on shrubs and low-hanging branches.

A Study That Raises New Questions

This study not only sheds light on mastodon evolution but also opens the door for new research inquiries. As Emil Karpinski, lead author and former graduate student at McMaster's Ancient DNA Center, notes, "How did these disparate species interact in Alberta? Did they compete or interbreed?" The exploration of these questions promises to deepen our understanding of these majestic creatures and their responses to a changing world.