Extinct Saber-toothed Cat (Smilodon fatalis) Fact Sheet: Physical Characteristics

Careful study of fossil bone or tooth anatomy yields much exact information about placement and strength of muscles, tendons, ligaments, nerves, and blood vessels. In rare cases, skin and hair impressions or actual skin or hair is preserved. Body weight is more difficult to gauge because fat leaves no impression on the skeleton.

General Description

• Similar in size to modern African Lion, but more robust with slightly shorter limbs.
• Nearly 18 cm long (7 inch) canine teeth (Homotherium's canines were around 10 cm or 4 in long.

Teeth

• Canine teeth blade-like, curved slightly back towards throat
  • Flattened and curved rather than more rounded like modern cats
  • Serrated on both edges
• Incisor (front) teeth are conical & set in curved row (rather than flatter, in a straight row as in modern cats)
• As in all cats, no molar teeth for chewing
• Jaw gape is enormous - approaching 130 degrees (compared to around 65 degrees for modern large cats)
  • Gape necessary for food items to get past the long canine teeth
• Canines of saber toothed cats more resistant to bending and breaking than round canines (Christiansen 2007)
• Bite force strong enough to put strain on skull where jaw muscles attached (Duckler 1997)
• Computer models suggest bite only one-third as powerful as that of modern lions (McHenry 2007)
• Bite may not have been used to hold prey immobile; prey restrained with paws prior to inflicting the killing bite (McHenry 2007)
• Teeth may be used to roughly gauge age as shown in a study of a population from Rancho La Brea (Meachen-Samuels & Binder 2009)
  • Dentin fills in pulp cavity as animal ages
  • Young middle and old age assessments possible
  • If approximate age is known, when this info combined with measures of jaw length, possible to separate a group of fossils into male vs female (otherwise large old females and males, for example, can be confused with younger, smaller males - size alone can't be used)

Pelage

• Not known; camouflage coloring (spots, stripes, marbling) might have helped this robust predator stalk prey. (Jefferson 2001)

• Very little or none; few differences between sexes in teeth, skull, and skeleton. (Van Valkenburgh & Sacco 2002)
• Sexual dimorphism not present (Meachen-Samuels and Binder 2009)
  • Males not distinguishable from females based on size
  • Male aggression assumed to be less pronounced than in more dimorphic extinct American Lions (P. atrox)
  
  

• Strong retractable claws
• Front and back limbs about the same length
• Short tail, unlike modern large cats
• Not much "chin" on lower jaw to brace the long upper canine teeth
• Other saber tooth cats like Homotherium have "chin"
• Flexible hyoid bone supporting the tongue similar to modern lion's may have allowed Smilodon to roar
• Brain of Smilodonhad furrows like all modern cats, indicating similar hearing, eyesight and limb coordination (Turner 1997)
• Brain anatomy revealed in natural and lab-made casts that fill the brain cavity of a fossil skull

Christiansen (2007)
Christiansen & Harris (2005)
Jefferson (2001)
Shaw & Cox (2006)
Turner (1997)
Van Valkenburgh & Sacco (2002)