Hailey Faurot

The characteristics that contributed to megafauna extinction in the Quaternary Period (over the last 2.6 million years)

jenebauerLeave a comment

Phylogenetic Evidence Supports the Effect of Traits on Late-Quaternary Megafauna Extinction in the Context of Human Activity

By: Rhys Taylor Lemoine, Robert Buitenwerf, Sören Faurby, and Jens-Christian Svenning

Summarized by: Hailey Faurot is a senior Environmental Science Ecosystems major at Binghamton University minoring in History. She plans to pursue a career in environmental education and/or wildlife conservation. In her free time, she likes to birdwatch, dance, play music, and spend time with family and friends. 

What data were used? Scientists collected data concerning the extinction status of 548 mammal species, 196 still extant (alive today in the wild), which was compared with the evolution of the absence or preservation of 17 traits that were selected from preexisting datasets. These traits included Paleotropical occurrence, phylogenetic link to the paleotropics (the historically warmer regions of the planet), insularity, body mass, limb morphology (walking style– on their toes (like a dog), their entire foot (like elephants), etc., arboreality (to what degree did they live in trees), molar morphology (tooth variations), guild, fermentation (how did their digestive system work), home range (size of their geographic range), dispersal distance (how far they spread out), native range (size of the area they were originally from), temperature range (what temperatures did they tolerate), precipitation range, activity cycle (nocturnal, etc.), encephalization quotient (how large their brain was compared to their body), and generation time (how long it takes them to produce offspring). These traits fell into the categories of functional, biogeographical, and phylogenetic. 

Results: The researchers found that three of the 17 traits were the most significantly impactful in the risk of extinction. These traits, outlined below, led to greater extinction largely because of their relationship to human hunting techniques and preferential hunting by humans towards animals with these traits. 

  1. The researchers found that modern species that were more closely related to paleotropical species were at a lesser risk of modern extinction 
  2. Plantigrade species, animals who walk on a flat foot, such as bears and elephants were more at risk of extinction 
  3. Island endemic species (those specific to an island location and not found elsewhere) were more likely to go extinct 
  4. Larger bodied species were at a higher risk of modern extinction compared to the other species in the study 
Figure 1 contains four graphs labeled A, B, C, and D. Graph A uses a bar chart with an x-axis labeled to represent the bars “continental” and “insular”, and a y-axis of 0-1 representing a proportion of all species surveyed to show the relationship between Insularity and Extinction, depicting insular species being a greater proportion of extinct species and placing a silhouette of deer above each bar. Graph B depicts nonplantigrade species as being extinct in greater proportion than plantigrade and has a silhouette of a wolf above the “non-plantigrade” bar and a silhouette of a bear above the “plantigrade” bar. Graph C depicts the relationship between phylogenetic distance to paleotropical relative and extinction and depicts an armadillo on the left side of the graph and an elephant on the right side, showing that the majority of extinct mammals have low phylogenetic distance to their paleotropical relative and the majority of extant mammals have high phylogenetic distance to their paleotropical relative. Graph D depicts the relationship between body mass and extinction, the number of extinct and extant species increases with body mass.
Figure 1. Graph A in the above figure depicted the proportion of extinct and extant species of each group of mammals, comparing those that live on mainland continents (continental) and island-dwelling species (insular). Graph B depicts the proportion of extinction of limb morphology, comparing not plantigrade vs plantigrade (flat footed) of each animal. Figure C represents the proportions of extinct mammals and extant mammals that have high and low phylogenetic distance to their paleotropical relative. An example of a modern day mammal and its paleotropical relative would be the modern three-toed sloth and the extinct giant ground sloth. Figure D represents the proportions of extinct and extant mammals by body mass. The axes have been rescaled mathematically for easier visualization.

Why is this study important? This study is important because it helps us understand the traits that extinct species possessed that may have contributed to their extinction or to their survival at the hands of human hunters and other environmental factors throughout the Quaternary Period. Larger-bodied species were disproportionately at greater extinction rates because early humans could hunt them with tools and were likely motivated to do so because of the large amount of meat that could be sourced from these animals. Island endemic species were more prone to extinction by human and other factors because of their limited range size. Lastly, plantigrade species (those that walked on the entire soles of their feet) were able to be exploited by humans because of their slower movement. 

Broader Implications beyond this study: This study’s results have broader implications beyond the field of paleontology, including effects on ecology and wildlife management. If we can specifically pinpoint phylogenetic traits that caused life to go extinct in the past, we can more appropriately manage wildlife in the present, specifically against threats such as poaching and illegal harvesting by humans. 

Citation:  Lemoine, Rhys Taylor, Robert Buitenwerf, Sören Faurby, and Jens-Christian Svenning. 2025. “Phylogenetic Evidence Supports the Effect of Traits on Late-Quaternary Megafauna Extinction in the Context of Human Activity.” Global Ecology and Biogeography 34(7): e70078. doi:10.1111/geb.70078.