Imagine you are at a research camp in the Tanzanian grasslands and you need to relieve yourself. You walk to the nearby pit toilet: a concrete slab with a tiny portal that opens into an eight-foot pit heaped with human waste. You drop your pants, squat and carry out your business. Suddenly you realize you are not alone. Maybe it is a slight gust of air, or something even more corporeal.
“I’ve had the soft, leathery caress of a bat’s wing against my buttocks while having a poo,” said Leejiah Dorward, a postdoctoral researcher at Bangor University in Wales.
In Tanzania, the spaces under certain pit latrines have become cozy havens for roosting bats, according to a paper published by Dr. Dorward and colleagues in September in the African Journal of Ecology. The researchers found the pits’ rotting depths warm the air, and the concrete slab overhead keeps predators out. Even the occasional falling feces or overhead spray does not drive the bats away, though they may startle the animals into flight.
“Suddenly you would feel one charge upwards and launch itself between your legs,” said Amy Dickman, a senior research fellow at Oxford University and director of the Ruaha Carnivore Project in Tanzania. “Then you have this furry mammal just flying into your behind.” Though Dr. Dickman was not involved with the research, her toilet was one of seven examined by Dr. Dorward.
Dr. Dorward first encountered the bats in 2015 at Dr. Dickman’s research camp near Ruaha National Park (where he first felt the velvety kiss of furred wings on his derrière), but toilet bats may be familiar bathroom buddies to anyone who has used pit latrines in certain parts of Africa.
Sospeter Kibiwot, a bat ecologist at the University of Eldoret in Kenya, first saw a toilet bat when he was in elementary school, an encounter that both spooked him and inspired him to learn more about bats. “Since my childhood, I have spotted more than 10 pit-latrine roosts,” Mr. Kibiwot wrote in an email. “Not all such latrines are roosts but just a few.”
Members of the conservation organization Global South Bats have seen bats roosting in latrines in Zambia and Madagascar and in sewage systems in Mauritius, according to Angelica Menchaca, the group’s general director.
Realizing the phenomenon seemed absent from scientific literature, Dr. Dorward began to survey the pit toilets around camp for potential occupants in 2017. His first surveilling method was to photograph the bats. His…