You may not take a second look at a pile of bat poop gathered for 4,300 years, but a group of scientists has provided an intriguing insight into how bat diets and therefore weather conditions have changed over thousands of years. ‘years.
Taller than the average man (2 feet or 6 feet and a half), the pile of poop (also known as guano) records history in clear layers, like sediments under a lake.
By analyzing the layers back through time, scientists have been able to find out changes in the diets of bats that have been inhabiting this cave for millennia.
In turn, dietary changes provide suggestions on what the climate and environment might have been like during that time, with temperature and precipitation variations affecting animal life and the types of insects and plants available for bat eating.
“We study natural archives and reconstruct natural histories, mostly from lake sediments,” says limnologist Jules Blais of the University of Ottawa, Canada. “This is the first time scientists have interpreted past bat diets, to our knowledge.”
Thin blades of bat guano core. (Chris Grooms)
The researchers were especially interested in sterols, biochemical markers of the diet produced by plant and animal cells. These sterols cross the digestive tract and can be stored for thousands of years, as happened here.
An analysis was also made of the poop of bats currently living in the same place: the Home Away from Home Cave in Jamaica, which currently houses about 5,000 bats of five different species. This gave the team a baseline to work on.
Researchers found that there was an increase in plant sterols in the diet of bats about a thousand years ago, which corresponded to the warm medieval period (900-1,300 AD), when the Americas were believed to be particularly dry.
Another ear of plant cholesterol was found around 1,350 BC, at a time known as the Minoa warm period. Drier conditions often make life difficult for insects, and during these times bats ate fruit more often.
“We deduced from our results that past weather has had an effect on bats,” says biologist Lauren Gallant of the University of Ottawa. “Given current climate change, we expect to see changes in the way bats interact with the environment. This could have consequences for ecosystems.”
Another interesting discovery was the changes in the carbon composition of guano, which probably correlated with the arrival of sugar cane in Jamaica in the 15th century. Chemical signatures of human activities such as nuclear testing and the arrival of lead gas could also be observed.
Bats are more important to ecosystems than you might have noticed: they control insect populations, pollinate flowers, and disperse seeds. This rock method is an effective and non-invasive way to study your diets and check your well-being through a history that, with the right pile of guano, can extend back thousands of years.
It is also worth noting that the same techniques used here can be applied to other caves around the world, according to researchers, which can be especially useful in areas without lakes and underlying sediments, which reveal much of the same information about the weather weather.
“As work that shows what can be done with poop, this study opens a new path,” says geologist Michael Bird of James Cook University in Australia, who did not participate in the new study.
“They really expanded the set of tools that can be used in guano depots around the world.”
The research has been published in Journal of Geophysical Research: Biogeosciences.