Extinct Dire Wolf (Canus dirus) Fact Sheet: Diseases & Pathology

Abnormalities in fossils bones may show evidence of arthritis, cancer, nutritional stress, fractures and more.

• In a study of the general health of several Pleistocene animals (as revealed by x-rays of their bones), dire wolves' health appeared no different than that of modern healthy populations of carnivores.
  • Bone x-rays can show lines where normal growth is halted and later resumed (called Harris lines)
  • Frequency of Harris lines very low, similar to health wolves on Isle Royale
• Dental enamel of fossil dire wolves from La Brea tar seeps show almost no defects; a healthy population is indicated even shortly before their extinction.
• Tooth breakage commonly seen in fossils from La Brea (Binder et al 2007)
  • Broken teeth a feature of living carnivores that often crack large bones.
  • Tooth breakage data in fossils must be combined with accurate estimates of an animal's age (so that estimates of breakage are independent of an animal's age)
• Dire wolf fossils from La Brea at 15,000 years ago show more tooth breakage than ones from 12,000 years ago. (Binder et al 2002)
  • Perhaps this reflects more complete consumption of carcasses at 15,000 years ago and more competition with other predators than at 12,000 years ago when predator densities may have been lower.

Duckler & Van Valkenburgh (1998)
Binder et al. (2002)