Research utilizing ancient DNA has shed light on the complex evolutionary ties and ecological responses of elephants and their relatives. In a recent study, scientists sequenced the mitochondrial genomes of various mastodons, including five specimens from Nova Scotia and the East Coast—one dating back approximately 500,000 years—as well as a unique specimen of Pacific Mastodon from Chulatin, Oregon, and a partial mitochondrial genome from North Ontario. Their findings indicate that Pacific mastodons belong to distinct and deep mitochondrial lineages, indicating this species’ range extended into western Canada and potentially even Mexico. Additionally, the authors discovered evidence of at least three separate expansions into the northeastern coastal region and identified two new groups of mastodons with clear, geographically coinciding specimens.
Adult Mastodon (Mammuthus sp.) consumes spruce branches, set against a backdrop that suggests periodic continental migrations related to climate change. During the Middle and Late Pleistocene, at least two types of mastodons roamed North America: the American mastodon, spanning from the East Coast to central regions, and the Pacific mastodon, found from central Alberta to central California. Image credit: Kathryn Kilukki.
Mastodons were originally classified into numerous separate species but were later consolidated into one, the American Mastodon (Mammut americanum).
Recent classifications have been updated to potentially recognize at least two distinct species: American mastodon and Pacific mastodon (Mammut pacificus), with ongoing debates regarding their division.
Genetic analyses confirmed that Pacific mastodons are ancient and belong to separate genetic lineages that extend further than previously thought.
Notably, Alberta emerged as a “hotspot” where Pacific and American mastodons may have gathered, expanding northward and hybridizing.
Samples collected from the East Coast and northern Ontario revealed two genetically distinct groups, referred to as mastodon clades, cohabiting the same geographic area.
Surprisingly, the eastern species exhibit significant diversity, reflecting at least three distinct waves of migration. This pattern is driven by repeated climatic warming events that opened new areas for glacial retreat and northward movement.
As temperatures decreased and glaciers expanded, mastodons were either forced southward or faced local extinction.
“The data reframes our understanding of the modern regions known as Alberta and the North, highlighting their role as migratory corridors for surrounding fauna,” the researchers noted.
Moreover, a unique and genetically distinct lineage of Mexican mastodon was identified, possibly representing a deeper evolutionary branch of the Pacific mastodon or even a brand-new third species.
During the Ice Age, the mastodon was among the largest terrestrial animals on the planet, traversing a range from Beringia (now Alaska and Yukon) through Nova Scotia and south to Central Mexico.
These creatures primarily foraged in wetlands, consuming shrubs and branches, and inhabited environments quite different from those of their well-known distant relatives, the woolly mammoths.
“This study marks significant milestones, including advancements in our understanding of the Pacific Mastodon,” stated Emil Kalpinski, a researcher at Harvard Medical School.
“It also raises numerous intriguing questions: How did these distant mastodon species interact within Alberta?”
“Did they compete for resources or, as our lab’s earlier research indicated for mammoths, engage in breeding?”
“These revelations, in conjunction with findings from our 2020 study, enrich our understanding of how mastodons migrated and diversified across North America, aiding contemporary conservation efforts in preparing for ongoing climate change and migratory species in the North,” the researchers concluded.
Their paper was published on September 12, 2025, in the journal Advances in Science.
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Emil Kalpinski et al. 2025. Repeated climate-driven dispersion and speciation in peripheral populations of Pleistocene mastodon. Advances in Science 11 (37); doi:10.1126/sciadv.adw2240
Source: www.sci.news
