Extinct American Lion (Panthera atrox) Fact Sheet: Behavior & Ecology

Since direct observation of a fossil animal's behavior isn't possible, paleontologists use comparison and contrast with living animals for guidance. Tracks can sometimes reveal further clues to behavior. At a fossil site, the mix of plant and animal species gives clues to the ecosystem of that time and place.

• Pleistocene lions assumed to be social because of skeletal differences between sexes (sexual dimorphism):
  • Males have large canines
  • Males have prominent midline crest on the skull
  • Modern lions with these traits have breeding system with much competition between males
• Pleistocene lions assumed to be solitary because of roughly equal numbers of male and female P. atroxat La Brea Tar Pits (Jefferson 1992)
  • Statistics (128 males vs 100 females) suggest either solitary hunting or hunting by pairs, not prides (Jefferson 2001)
• When lions were painted by paleolithic artists, they were sometimes depicted in groups, as with social females today.
• Genetic studies suggest modern lions arose from a single population of maned individuals that replaced older mane less Pleistocene populations (Yamaguchi et al 2004)
  • Mane-less lions, however, could have been social before manes evolved.

• These large cats were keystone species in their habitats, like lions today
• Competition with other large predators such as saber-toothed cats and giant bears more intense than between large carnivores today.
  • Frequency of fossils tooth breakage suggests this pattern (Van Valkenburgh & Hertel 1993)
• P. atrox extinction probably a due to combination of climate change and ecosystem disruption by paleolithic humans

Jefferson (1992, 2001)
Van Valkenburgh and Hertel (1993)
Yamaguchi et al. (2004)