Monday, July 11, 2022

Mastodon Home Range

Environmental & Science Education, STEM, Global Change, Wildlife, Biodiversity, Biological Evolution


Did you ever wonder how mastodons spent their year or even whether scientists could ever find out?  Well scientists have at least learned how one American Mastodon (Mammut americanum), thanks to a tool developed by physical chemists. You might think of this as better science through chemistry: the use of chemical signatures.

There is an article in the New York Times (behind a subscription wall). My guess is that the reporting is in the Science Section for June 21. The science journal Nature has a short article accessible by members only.

The research was published in the Proceedings of the National Academy of Sciences (PNAS) and is completely accessible as a technical paper. It includes some maps that will help you locate the mating ground section of the home range and the core range what is now Indiana. The distance between the two was 150 Km (~93 miles). The adult was a breeding bull and died at 34 years of age from a wound, likely a skull puncture incurred in a battle for breeding rights.

Included below is the full significance section of the paper, a requirement of some journals that I like and some parts of the abstract that inform the significance section.

From the Significance Section

Fossil remains usually reveal little about lifetime landscape use beyond place of death, but ever-growing tusks of American mastodons (Mammut americanum) record this fundamental aspect of paleobiology. Using oxygen and strontium isotopes from a serially sampled male mastodon tusk, we reconstruct changing patterns of landscape use during his life. We find clear shifts in landscape use during adolescence and following maturation to adulthood, including increased monthly movements and development of a summer-only range and mating ground. The mastodon died in his inferred summer mating ground, far from landscapes used during other seasons. Mastodons had long gestation times, and late Pleistocene populations lived in harsh, rapidly changing environments. Seasonal landscape use and migration were likely critical for maximizing mastodon reproductive success.

Selections from the Abstract.

--The  two serially sampled intervals (5+ adolescent years and 3+ adult years) in a male mastodon tusk (were tested) for changes in landscape use associated with maturation and reproductive phenology.

--The mastodon’s early adolescent home range was geographically restricted, with no evidence of seasonal preferences. Following inferred separation from the matriarchal herd (starting age 12 y), the adolescent male’s mobility increased as landscape use expanded away from his natal home range (likely central Indiana). As an adult, the mastodon’s monthly movements increased further. Landscape use also became seasonally structured, with some areas, including northeast Indiana, used only during the inferred mastodon mating season (spring/summer). 
Here is a less technical entry on radiometric dating from the Simple English Wikipedia.

I hope you take a look at this paper. The maps are very useful.This research is fascinating and important ecologically and in the study of biological evolution.

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