The BBC website covers the publication of a study in the Proceedings of the National Academy of Sciences of USA. The study is called 'History of Animals using Isotope Records (HAIR): A 6-year dietary history of one family of African elephants' and it focused on studying the tail hairs of a single family of African elephants over a period of six years.
The BBC website reports:
The study shows how the elephants lost out to cattle grazing on grasses.
It also shows the rate of conception rising as food and water resources become more abundant each year.
The abstract of the study on the Proceedings of the National Academy of Sciences website explains
The dietary and movement history of individual animals can be studied using stable isotope records in animal tissues, providing insight into long-term ecological dynamics and a species niche.
We provide a 6-year history of elephant diet by examining tail hair collected from 4 elephants in the same social family unit in northern Kenya. Sequential measurements of carbon, nitrogen, and hydrogen isotope rations in hair provide a weekly record of diet and water resources. Carbon isotope ratios were well correlated with satellite-based measurements of the normalized difference vegetation index (NDVI) of the region occupied by the elephants as recorded by the global positioning system (GPS) movement record.
The ability to extract time-specific longitudinal records on animal diets, and therefore the ecological history of an organism and its environment, provides an avenue for understanding the impact of climate dynamics and land-use change on animal foraging behavior and habitat relations.
The BBC spoke to Thure Cerling, the University of Utah professor who leads the research
"When the rainy season comes you get this big sprouting of grasses, but they can't access it until it is 30 to 50 centimetres high," Professor Cerling said. "It's got to grow tall enough before they can actually yank it off with their trunks.
"We have this one incident where they apparently missed an entire good season of grass resource; the GPS data shows that they were outside [Samburu National Reserve] in a community area where it appears that they had to compete with cattle.
"They got out-competed in that situation."
This study builds upon a paper published in 2006 by the same team of scientists:
Stable isotopes in elephant hair document migration patterns and diet changes.
Read
the full article on the BBC website.
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