Extinct Columbian (Mammuthus columbi) and Channel Island (M. exilis) Mammoths Fact Sheet: Reproduction & Development

Isotope studies of elements present fossil bones and tusks in microscopic quantities give information about timing of reproductive stress, and timing of nursing. Clues to stages of development come from tooth replacement patterns and closure of sutures in skull and limb bones.

•   Age at weaning, estimated about 5-6 years for one Woolly Mammoth calf (Rountrey 2006)
  • Elephant tusks grow continually and absorb carbon and nitrogen isotopes from food.
  • Milk is rich in one heavy isotope of nitrogen and low in a heavy carbon isotope when compared with plant food.
    • Scientists can thus determine the approximate time when dietary switch occurs
  • The long nursing period may reflect the stress of harsh Arctic conditions. Columbian mammoths may have nursed for less time.
  • Similar to that of African elephant in high-stress environment
• Onset of a male's prime reproductive period may be recorded as a decline in the growth rate of a tusk around 10-13 years (Fisher 1996)
  • Living elephants are similar
  • This study done with mastodont tusk; mammoths would probably be similar
• Tusk growth rates of adult females may record periods of pregnancy and nursing. (Fisher 1996)

• Juvenile M. columbi preyed upon by the sabertooth cat, Homotherium (Kurtén & Anderson 1980)
  • 441 milk teeth of mammoth calves found in Freisenhahn Cave, Texas along with sabertooth cat remains
• Starvation, accidents, and human hunters were the main causes of death of adult mammoths (Martin 2005)
  • Old age individuals (between 55 and 70 years) would starve when their last set of teeth were worn down
  • Some 20 archaeological sites in North America have Clovis points associated with M. columbi bones.
• Human hunters and climate change are causes most often suggested for the extinction of most of the mammoths around 13,000 years ago. (Martin 2005)
• Recent studies say a comet's impact caused extinction of M. columbi and other large Ice Ages animals; this idea has now been challenged. (Kerr 2008)

Fisher (1996)
Kerr (2008)
Kurtén & Anderson (1980)
Martin (2005)
Rountrey (2006)