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Night out with the bats

They are not blind. Don't brand them as bad omens. Vampire bats are not found in India. We bust these and other myths as BNHS mammalogist Dr Bandana Aul takes us on a delightful fact trail of these mammals, especially since now is the ideal time to spot a few in Mumbai

Believe it or not but Mumbai is actually a great place to spot bats! Before we get into how to spot these mammals, here's a backgrounder on this species.

Bats

Bats are found in tropical, temperate and desert areas throughout the world except in extreme desert and artic regions. Bats are the second most diverse mammalian order after rodents in India, with approximately 120 species. Here's a list:

1. Old World Fruit Bats (Megachiroptera):
These are the fruit eating species and seen around human settlements. The most common one is the Indian Flying Fox commonly seen on Ficus trees in large aggregations during the day. A roost close to the Hornbill House, in the premises of the CSMVS, can be seen easily during the day. These form the group of Mega-bats. They have large eyes, small ears, large bodies, and have a dog/ fox-like face and so are frequently referred to as Flying Foxes. They either eat fruit or drink nectar from flowers. They have been misunderstood to be farmer's pests; on the contrary, they are pollinators of economically important species in forests, including cash crops such as mango, cashew, balsa, agave, and bananas. They are roost-loyal, and rarely change roosts unless disturbed.

The largest resident bat in India is the Giant Indian Flying Fox (Pteropus giganteus)
The largest resident bat in India is the Giant Indian Flying Fox (Pteropus giganteus)

2. Mouse Tailed Bats (Rhinopoma):
These appear like the Sheath Tailed Bats but are different in having a free tail and hence, the name Mouse Tailed.

3. Sheath Tailed bats (Emballonuridae):
These are the high canopy fliers and roost in the tiniest of crevices. BNHS has spotted T Melanopogon in Kanheri Caves. It also roosts in abandoned buildings and forts.

Pteropus faunulus is endemic to Central Nicobar
Pteropus faunulus is endemic to Central Nicobar

4. False Vampire bats (Megadermatidae):
These are carnivourous bats and feed on frogs, snakes, lizards and bigger insects. They stay in groups of 10-15 and can roost in caves, and tree hollows. They have been recorded by the BNHS on Elephanta Island.

5. Horse Shoe bats (Rhinolophidae):
These are ordinarily forest dwelling species and have not been seen in areas where disturbance is more prominent. They have not been recorded in Mumbai presently.

Close-up of the Megaderma spasma, also known as the False Vampire Bat.
Close-up of the Megaderma spasma, also known as the False Vampire Bat. PICS COURTESY/ BANDANA AUL, BNHS

6. Leaf Nosed bats (Hipposideridae):
They are commonly seen near habitation and appear to adapt to surroundings, and can stay in abandoned buildings, caves and forts. They seem to adapt to the disturbance around them.

Dr Bandana Aul
Dr Bandana Aul

7. Evening Bats (Vespertoinidae):
These are large in numbers and are seen to be the first to come out for feeding in the evenings. They stay in buildings, abandoned areas and caves. Small in size, they are swift in flight.This list of species includes those recorded all over Maharashtra, and not only Mumbai. Five species were listed from Kanheri and Elephanta with records dating to the 1980s but lack of monitoring and follow-up studies have created a gap in species patterns. This coupled with developmental activities has changed the previous roosts and so they could not record any species from the Kanheri Caves. They recorded three species in Elephanta Caves with one of the species vacating the cave in the dry season. Overall, BNHS has been able to record the following species in Mumbai through field and direct observation:

>> Pteropus giganteus
>> Cyonterus sphinx
>> Rousettus leschenaulti
>> Taphozous melanopogon
>> Megaderma lyra
>> Hipposideros fulvus
>> Scotophilus heathii
>> Pipistrellus sp
>> Kerivola picta

The bat factfile

>> Bats belong to the order of Chiroptera, with 1,001 species. Bats are unique in being the only group of mammals that, like birds, have sustained flight.

Bats
A roost of bats

>> Maharashtra is home to the colourful Painted Bat (Kerivola picta). This species roosts in dried leaves of banana trees, which helps camouflage the roost.

>> The smaller, Micro-Bats are found across India. These have large ears, small eyes, small bodies, and use echolocation, or radar, to find food. Usually insectivorous or carnivorous, they don't weigh over 25g. Look for them flying around light poles at dusk. They live in tree hollows, caves, buildings, rock crevices, and under bridges.

>> There are also Orange Bats, Brown Bat and Yellow House Bat (Scotophilus heathii). You can spot a roost of the Yellow House Bat on Elephanta Island, in the first, main cave.

>> Bats have one baby a year; they are called pups. Tropical fruit bats deliver twice a year. Babies weigh about 25% of an adult at birth.

>> Bats live for 10-20 years. Some live up to 30 years.  

>>  Bats hang upside down most of the time. Blood doesn't rush to their head because they don't weigh enough for gravity to affect circulation. They only hang upright to defecate and when they are about to deliver.

Busting bat myths
Owing to their nocturnal habits, dark dwelling places and gaps in scientific knowledge, there are misconceptions and taboos attached to bats.

Myth 1 > All bats are vampires. Bat's bite will turn you into a vampire and can lead to rabies.
This is untrue. India has no vampire bats; only False Vampire Bat exists that feed on frogs, fish and lizards, and not on blood. Vampire bats are restricted to Central America. Bat bites may lead to rabies but this is not reported from India. Bats can be vectors for some diseases, but only if it is handled by humans is the likelihood of a transfer. Few bats contract rabies. Over 50 years, less than 40 people have gotten rabies from a wild bat.  Scientific studies have shown that less than 1% of wild bats test positive for rabies. This hasn't been researched in India.
NOTE: If a bat bites you, visit a physician

Myth 2> Bats are blind and attack human beings.
Bats are not blind. They have an extremely well-developed sense of smell, sound and vision and are able to avoid bumping into objects in their path. Insectivorous bats are directed by their ability to emit ultra-high frequencies and supersonic waves to locate their prey known as Echolocation, while Fruit Bats locate their food by vision and smell. They sleep all day, are nocturnal and can see in the dark. So, the phrase “as blind as a bat” is untrue.

Myth 3> Bats damage orchards.
A Fruit Bat is regarded as a pest of orchards as they are believed to cause damage to the crop by eating the fruits before harvest. This is untrue as they consume strong smelling overripe fruits and most of the fruit collection by the owners commences before the ripening to reduce damage during transportation.

Myth 4> Bat Droppings (Guano) are poisonous and smelly.
Sometimes, when bats roost in buildings it may cause a problem due to dropping deposits. Droppings are dry and consist of insect wings or body remains. These are dry; though bat urine may be slightly offensive in case of large numbers in the same place. Contrary to belief, when bats roost in large numbers, the droppings accumulate such that it can be used as a fertiliser. Bats roost in abandoned sites or where disturbance is minimal. In fact, in some countries, bat guano is used as a fertiliser as it is rich in nutrients. It is largely due to confined spaces, large roosts, humidity and lack of circulation that bat guano may cause offensive odours.

Myth 5> Bats are birds.
Bats give birth to young ones known as pups; their uniqueness being that they are the only mammals gifted with the art of flight. Bats range from the Giant Fruit Bats with wing spans approaching 6ft (approx 2m) to Insect Eating  Bat that measures 1 inch (3cm) long and the weight ranging from 2 pounds (1,000gm) to less than 1/15th of an ounce (2gm). India's largest resident bat is the seasonal migrant — the Giant Indian Flying Fox (Pteropus giganteus).

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