Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world
Species: Malayan flying lemur (Galeopterus variegatus)
Habitat: Rainforests and plantations of South-East Asia
Take one look at a flying lemur, or colugo, sitting in a tree and it brings to mind a scrawny kid forced to wear his big brother's hand-me-downs. Flaps of skin hang around its ankles and get in the way as it clambers awkwardly around the forest.
Once the colugo leaps into the air, though, everything changes. Its baggy folds transform into enormous wings as the animal sails gracefully through the canopy.
With their bark-patterned fur and nocturnal habits, spotting these animals, which are about the size of large squirrels, is tough. This didn't deter Yamato Tsuji of Kyoto University, Japan, and his colleagues, who spent four years in the jungles of Indonesia studying them.
Colugos spend their days curled up in cracks and crevices in the rainforest trees, only emerging to snack on young leaves at night. They are particular about which tree species they sleep in, Tsuji and his team found, and above all favour tall, isolated trees standing high above the canopy.
Here they can hide from predators, such as civets and pythons. But if spotted, the lack of surrounding vegetation makes for a quick and easy getaway. It also gives them a nice launch pad for their dusk departure to feeding trees lower down in the canopy.
These animals are not technically flying, of course, but neither are they lemurs, though they are related. They belong to a family called the Cynocephalidae. The Philippine and Malayan flying lemurs are the only two species in this very exclusive club.
They lack the opposable thumbs of their primate cousins, which partly explains their ungainly, frog-like climbing technique, says Tsuji.
But what they lack in ability on the branches they more than make up for in the air. Colugos are the largest of the gliding mammals, and with an arm span of 70 centimetres, this makes for impressive "wings". Stretching from fingertip to tail tip they are big as physically possible. Even their fingers are webbed to maximise the glider's surface area. This feat of natural engineering allows flying lemurs glide over 130 metres while losing only around 10 metres in height - on a par with flying squirrels and other gliding mammals. During the day, the flaps double up as a cosy shelter for baby colugos as they cling to their mother's belly.
When it comes to landing, colugos have class. Since gliding is little more than falling with style, you might think it would end in a dramatic landing. Not a bit of it. Colugos can adjust their aerodynamics to slow themselves down significantly. Just before landing they angle their body upwards to reduce speed, landing softly on all fours with pinpoint accuracy.
These easy gliders suffer from habitat loss and hunting, but luckily, at the moment their numbers seem to be holding up reasonably well.
Journal reference: Mammal Study, DOI: 10.3106/041.040.0107
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