Tiny GPS backpacks shed light on nightlife of desert bats
If you've been wondering how to track your bats, wonder no longer. A team of researchers led by the University of Helsinki has used new miniaturized GPS tags to keep tabs on desert bats as they fly about in Sibiloi National Park, Northern Kenya. By plotting the movement of the night fliers, the study is designed to provide new insights into how they adapt to drier times of the year.
Wildlife tracking technology has proven an effective tool for naturalists for over half a century, but, until recently, a limiting factor has been the size of the equipment. It's one thing to tag something like a whale or an elephant, but something small like a bat is another thing entirely. This presents more than just a technical challenge because the only effective way of studying the behavior of something like a bat that flits about in the darkness like a shuttlecock on acid is by attaching some sort of tracking device to it.
For the University of Helsinki study, the researchers chose yellow-wing bats living on the shores of Lake Turkana, the world's largest desert lake, in Kenya. A species of false vampire bat found throughout sub-Saharan Africa south to northern Zambia, the yellow-wing is something of a chiropteran heavyweight, coming in at up to 36 g (1.27 oz) and has the ability to alter its wing geometry, allowing it to carry relatively heavy loads.
With this in mind, the Helsinki team captured 15 bats in the rainy season and 14 in the dry season using mist nets. After being examined, the 1.45-g (0.05-oz) tags were attached to the bats in the form of tiny backpacks that were glued to the animal's back using cyanoacrylate-based glue.
The bats were then released and allowed to flit about for a week as they hunted for their prey of soft- and hard-bodied insects and the tag traced their movements for up to an hour every night. They were then tracked down by means of a VHF transmitter in the tag, netted again, and the tag removed for data retrieval.
The team found that the yellow-wing bats, which are a home-loving species, traveled farther and longer at night during the dry seasons than they did during the rainy one – probably as a way to compensate for having less food available.
According to the team, this study not only sheds new light on the behavior of desert bats, but it also shows how animals can adapt to changing climates.
"The responses exhibited by bats offer important insights into the responses of other taxonomic groups," says Irene Conenna, a PhD candidate at the Faculty of Biological and Environmental Sciences. "These new miniaturized satellite-based tags now allow us to better understand how increased aridity affects bats foraging efficiency, leading us one step forward to understanding limits in aridity tolerance and impacts of climate change."
The research was published in Movement Ecology.
Source: University of Helsinki