We witness the power of flight often enough. Butterflies foraging for nectar, sparrows darting through the sky, mosquitoes buzzing around our ears and ankles, looking for a quick bite. There are thousands of creatures that can fly — and they all belong to just three groups of the vast animal kingdom: insects, birds, and bats.
In fact, bats are the only mammals on the planet that are capable of “true flight”. Aerial species, such as the Indian giant flying squirrel, glide rather than fly and need high perches to take off. Bats in comparison, use muscle power to propel themselves upwards, like birds. This evolutionary trait “pushed them to the edge of mammalness,” says American bat biologist Rick Adams, in “Betting on Bats for Genetic Treasures”.
But why, of all the mammals on Earth, did only bats evolve to fly?
Cover photo: Dhritiman Mukherjee
Bat experts (called chiropterologists) assert this is because of the crucial roles that bats play in an ecosystem. Like birds, bats drink nectar, eat fruit, and snack on bugs, and like their feathered counterparts, they pollinate flowers, disperse seeds, and check insect populations in the process. Except they do it at night, by the light of the moon. In regions where bat populations are threatened, a number of nocturnal species have also dwindled. Without their beloved bats, many plants — especially native species — are vulnerable. Without native species, herbivores lose vital sources of food. In this sense, bats are keepers of balance, as crucial to the night as bees are to the day.
After dark, they rely on their eyesight and powers of echolocation to find their way. Bats are fascinating commuters. They emit sounds through their mouth and nose, and use the echo that bounces back to create a mental image of the world around them. They can “determine if an object is moving — and if so, how fast,” explains a piece in the Telegraph called Bats – Nature’s most misunderstood animal. “It is bats’ echolocation that makes them masters of the dark: swooping and wheeling with absolute precision, they can snap up moths and insects on the wing.” Far from blind, bats perceive far more detail than the human eye.
But not all species have these abilities, explains ecologist and PhD student Rohit Chakravarty, who is currently studying bats in Uttarakhand. “In India, only insectivorous bats use sound to navigate, fruit bats rely on sight and smell,” he says. Unfortunately, most of India’s bat species — save for two — receive no legal protection. On the contrary, our fruit bats are classified as vermin under India’s Wildlife Protection Act, and can be culled without consequence. The insectivorous species are vulnerable to hunting and habitat loss. It seems ironic, that while conservationists are working tirelessly to create sanctuaries for bats in India, on the other side of the world, genetic scientists are trying to sequence the genome of every living bat species on the planet.
Why? Because of their age.
As a generic thumb rule, the smaller the size of a mammal, the shorter its life span. Rats for instance, live for about one year in the wild; elephants can survive for 60 to 70 years. In this sense, bats are an anomaly. Despite their diminutive size, they live up to 30 years of age — and we have no idea why. It’s one of the many things we are yet to learn about these keepers of the night, the only mammal on Planet Earth that made the leap to flight.
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