Breaking A Sweat

Long-lived mammals might find it especially tough to deal with climate change because their populations grow slowly and they can’t easily move to a new habitat. But little research has been done on how global warming will affect these animals. Now, a study of more than 1,000 elephants has shown that hot weather can substantially lower their survival rate.

The authors analyzed data collected from 1965 to 2000 on 1,024 Asian elephants in Myanmar. These semi-captive animals help the timber industry by pushing and dragging logs. Each Myanmar timber elephant can train and work for about five decades, and detailed records of each animal are kept.

Monthly temperatures averaged 25 degrees Celsius during the study period and reached as high as 34 degrees, the team reports. Hotter weather was linked to lower survival; for example, 5.7 percent of calves died during periods with the highest temperatures, while only 2.3 percent died when the temperature was around 23 degrees.

Heat stroke and infectious diseases tended to account for a higher percentage of deaths during the hot months. “Overall, switching from good to bad climatic conditions within an average year approximately doubled the odds for mortality,” the team writes. Roberta Kwok | 9 January 2013

Source: Mumby, H.S. et al. 2013. Climatic variation and age-specific survival in Asian elephants from Myanmar. Ecology doi: 10.1890/12-0834.1.

Image © SOMMAI |