Reproductive, survival benefits of mothers, grandmothers in elephants

Research in Kenya sheds light on female elephant reproduction, aging

Date: January 19, 2016

Source: Springer

Only a few mammals and some birds are as long-lived as humans, and many of these species share interesting characteristics in how they age. A new paper in Springer's journal Behavioral Ecology and Sociobiology explores lifetime reproductive patterns in African elephants. Led by Phyllis Lee of the University of Stirling in the UK, the study analysed data from 834 female elephants in Amboseli National Park, Kenya. This population has been continuously monitored since 1972, and data collected on more than 3000 elephants since the study began. This paper analyses 42 years of data on females who survived to be at least nine years old.

For long-lived species such as humans, chimpanzees, whales and some birds, longer survival is associated with higher reproductive rates and a loss in fertility only at an extremely old age. Prolonged post-reproductive lifespans may mean potential advantages for both the surviving individuals and their offspring; post-reproductive longevity thus remains a question of major theoretical interest. Elephant life histories are slow; a 22 month gestation period is followed by 12 months lactational anestrus, and calves suckle until their next sibling is born. Most females in this study gave birth by the age of 14, and as for other species, early starters have higher rates of reproduction.

Continued …