It’s difficult to imagine a cuter bat than the Spix’s disk-winged bat (Thyroptera tricolor). A member of the thyropteridae family, this particular insect-feeding bat looks more like a round fuzz ball than an actual bat. The bat lives in South America, where it consumes approximately 0.8 grams of insects every single night.
Physically, the most interesting thing about the Spix’s disk-winged bat is the small disks located on both their hind feet and thumbs. It’s these discs that allows the species to easily crawl all over the leaves they love roosting in.
The Spix’s disc-winged has a few lifestyle choices that set it apart from other kinds of bats. Instead of roosting in caves or hollowed out trees, they prefer to set up house in leaves which start out tightly furled and uncurl as the day goes on. The nature of the leaves forces the bats to find a new leaf to roost in every single day.
Another interesting thing about the Spix’s disc-winged is that it likes to live in groups that consist of four to six bats. They form a close family unit and will stay together for several years. Something that’s rarely seen in other bat species.
Research indicates that while the bats are quite close and are very talkative, they have a difficult time determining when they’re communicating with a long-term roost mate or a complete stranger. It turns out that the rolled up leaf design is a key aspect of helping them determine who they’re talking to and letting their friends know about the newest digs.
Proving the rolled leaves aid in bat communication required a team of scientists to record an array of bat calls. About eighty of the calls were the single note calls the species uses while they’re trying to connect with their roost mates. Another sixty-five calls were recorded. These calls represent the response to the where are you cry. The response includes more than twenty different sounds.
The research team placed a recorded both in and outside a leaf and used a microphone with an attached recorder to capture the response.
The results disproved their theory that the leaves served as a megaphone, making it easy for flying bats to identify their roost mates. It turned out that the recording that was played within the leaf was only a decibel higher than the one that was played outside the leaf.
However, just because the hypothesis was disproven, it doesn’t mean the experiment didn’t reveal some interesting information. Where the leaf made a big difference was how well the bats who were already tucked inside their new roost received the location call from their missing roost mate. The sound the leaf funneled into it was a full ten decibels louder.
The results also presented the team with a reason why the bats struggled to recognize the call of their friends. The response call is flattened and distorted by the leaf. In order to make up for this problem, the bats send a representative to hang out outside the leaf and establish that the owner of the response call is a bat they know.