Urban Wildlife Series: Indian Flying Fox (Pteropus medius)

To understand how big an Indian flying fox (Pteropus medius) can be, you have to see one in person. Upon seeing one up close you half expect it to swoop down, punch you in the face (because you didn’t bother to put that toffee wrapper in the bin) and growl “I’m Batman” before vanishing into the darkness. Apart from their size, they’re notorious for their mind-bogglingly large colonies on isolated, large trees in rural or urban areas, preferably near a good source of water. Why near water you might ask? Well it’s because they lose a substantial amount of water compared to their size, because of the large surface area their wings occupy. Hence, they have a large requirement for water compared to other animals of similar size and weight. 

They do tend to keep a low profile and try to keep it down a notch, but if it gets too hot (like it always does at noon in Sri Lanka) or if they have too many mouths for per fruit, they express their discomfort quite raucously (somewhat similar to a Colombo school Big Match at maximum capacity. Loud right?) and flap their wings around to regulate the excess heat. The wings of a fruit bat are highly vascularized. which means that there’s a large network blood vessels within them. So when they flap their wings the outside air cools the blood flowing through the vessels, thereby cooling their bodies effectively (DIY aircon anyone?). Living near large bodies of water also allows them to take advantage of the cool air circulating over the water, and also allows them to rehydrate easily. But when the air temperature dips and it gets comparatively cooler, they wrap their leathery wings around themselves and relax.

These bats are mainly frugivorous and nectarivorous, which means that their diet mainly consists of ripening or overripe fruits (mango, cashew plums, plantains, guava, figs and papaw) and the nectar of flowers, respectively. This is another explanation as to why they choose to roost near rural and urban areas. It is because of the ease of access to rural and urban gardens which are more often than not, full of fruit trees, unlike dense forests (inside of which bat colonies are never found). 

Bats are for the large part, nocturnal creatures and are known for their echolocation abilities which enable them to navigate around obstacles and catch prey in extremely low visibility conditions. Flying foxes on the other hand, use their keen sense of smell and large sensitive eyes to locate their favorite fruit trees. Their immense love for all things fruit has labeled them as vermin by fruit farmers, due to the sheer amount of cash crop that they consume (much like when Obelix [Jim Pappa] goes to that one restaurant and just polishes off all the dishes, causing the chef a hysterical nervous breakdown). As a result, many farmers are known to destroy any flying fox roosts that are near important crop lands. 

But the thing that most people don’t know, is that flying foxes are extremely important for the pollination and seed propagation of a large number of plant species. Thus outweighing their destructive feeding habits. Plus they tend to target overripe fruit which doesn’t have a long shelf life anyway. There are however ways of mitigating the damage caused by flying foxes to crops. Erecting netting around the crops, picking them on time, or planting Jam Fruit Trees (Muntingia sp.) around the crops would be the best sustainable method of deterrence. Why? Because they love jam fruit, and so do the pale-billed flowerpecker (Dicaeum erythrorhynchos), a bird no larger than a human palm, capable of zipping around branches like a kid on a sugar rush, while gorging down jam fruits. 

Flying foxes are highly social creatures, as evident by their large colonies. Their social structure is a male dominated hierarchy and is structured like any corporate office where higher ranked males occupy the highest branches (Penthouse for the CEO) and lower branches for the low ranks (cubicles for the executives). Males are responsible for preventing outsiders from entering their roost. Like that Nelly Furtado song, Indian flying foxes are a promiscuous bunch. That is, they are polygynandrous, aka, mate with multiple partners. Come breeding season, male testes get bigger (supply and demand) and copulation occurs after a male corners a female after a lengthy chase. Mating season is from July to October with one to two pups per litter born six months after. Pups are born feet first, enabling them to grab onto its mother as soon as it is born. Pups are looked after by the females, as males are known to shoot and scoot, and are not involved in the rearing of the cubs.

Flying foxes, though adorable and ecologically important, are vectors for several viruses that can infect humans. The main ways to curb the transmission of zoonotic diseases is to take some pretty basic preventive measures. These could be as simple as safeguarding water sources used by humans from bat poop, not consuming fruits that have been partially consumed by a flying fox or any other animal, and so on. 

The most important thing is to not eat them, no matter how exotic or adventurous it sounds. They are not a food item! Though they may be a staple diet in many indigenous cultures, if you take the time to read about them (the people not the bats!), you learn that they are riddled with horrible diseases generation after generation, because of the diseases transmitted to them through the consumption of flying foxes and other bat species. This is one of the main reasons why bushmeat consumption and the exotic wildlife trade must be strictly mitigated.

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