Batman: H. C. Heg On Bats

In summer as children, we were allowed to stay out until dusk. In our northern part of the Central Time Zone, even on its eastern edge, dusk came late. I remember most the mosquitoes, fireflies, and bats. Some nights I would watch the bats as darkness fell. First there would be only one, then two, and by the time it became truly dark, there would be half a dozen or more swooping above us at what seemed a discreet distance. But who knew if they were even aware of us?

I would try to follow one with my eyes to judge its circuit. That was nearly impossible though because they were so quick, and their flight would take them through trees where I would lose sight of my mark for a second; then I couldn’t tell if it was my bat or another one I was watching. I imagined that the bats operated in little groups that patrolled a defined area with maybe six bats per cell. I imagined these cells occurring contiguously all over the county and then all over the state and ultimately all over the country; I figured there would be hundreds and thousands and millions of bats. Thinking about that, I got the same feeling as when I stared at the stars and tried to infer infinity.

In those days, bats were regarded as vermin that lived in attics, carried rabies, and were slightly creepy and, at best, of little or no use. Now as then, there are fears and misconceptions about bats.

Some of these are silly. That bats are attracted to human hair is one of those; or that they’ll get stuck in hair while hunting insects. Try throwing a stick into the air where bats are hunting overhead; they’ll immediately scatter, just as minnow do when a pebble is dropped into a pond. All the swooping and acrobatics that bats exhibit involve locating and catching insects in the dark on the wing; bats certainly can distinguish humans—and their sticks—from prey.

Some are accepted as figures of speech: “blind as a bat”. But bats are not blind. Some fruit bats have excellent night vision, which they use to find the flowers and fruits they pollinate and eat. In the dark, though, bats also “see” by echolocation. Bats emit a series of short, high-pitched sounds that bounce off objects and surfaces, creating an echo that the bat perceives. It’s an acutely sensitive system that allows bats to discriminate the size, shape, direction, distance, and motion of an object (insect, human, or otherwise) and that may have applications for blind people.

Some are a mixture of fancy and fact. Bats don’t attack people, but they can carry disease. They are highly mobile creatures that range far and wide in small groups and roost in large communal colonies, which make them good hosts for pathogens and excellent potential transmitters of disease.  However, the threat to humans in North America is minimal.

Rabies is the predominant disease concern. Rabies has been recognized for at least 4000 years and is typically transmitted in saliva from the bite of an infected animal. It’s a viral disease of warm-blooded animals (including humans) that affects the central nervous system. It’s most often seen in dogs, cats, raccoons, skunks, foxes, bats, and coyotes. The World Health Organization estimates that 55,000 people die from rabies each year, mostly from contact with rabid dogs, but in North America, pet and livestock vaccination programs have all but eliminated human rabies. An average of two people per year died from rabies transmitted by bats in North America between 1995 through 2009.

Among other things we know about bats is that they may look like winged rats, but they’re not rodents. They are far more closely related to humans than they are to rodents. Worldwide, there are as many as 1100 species of bats. Most (70%) eat insects; most of the rest eat fruit. There are three species of “vampire” (carnivorous)  bats that live in Central and South America (their teeth are not like hypodermic needles, though; they lap rather than suck blood).

Bats come in a variety of sizes. The smallest is the Kitti’s Hog-Nosed bat (Craseonycteris thonglongyai), also known as the bumblebee bat. It’s endangered, insectivorous, and lives in Southeast Asia. It’s about 1.25 inches long and is the world’s smallest mammal. The largest bat is the rare and endangered Giant Golden-Crowned Flying-Fox (Acerodon jubatus), a fruit bat that weighs nearly 3 pounds and has a wing span of almost 5 feet. It lives in the Philippines.

Bats are the single true flying mammal, and some are prodigious flyers. The hoary bat (Lasiurus cinereus) commonly occurs throughout North and South America. Like some other bats, it is migratory and will migrate from Canada to the southern USA; it is known also to have flown from North America to Hawaii (about 3000 miles). It is Hawaii’s only indigenous land mammal and is endangered there. It is predatory and prefers moths.

Migratory bats are the exception in the temperate North America. Most of our bats hibernate in caves (or mines) during winter; they roost in trees or buildings during summer.

Bats are not vermin. They play a significant ecological role. In desert and tropical climates, bats are important pollinators. Many tropical plants (mangoes, bananas, and guavas) are dependent on bats for pollination; some are entirely dependent on bats for pollination and seed distribution. In tropical rainforests, almost all seeds scattered in cleared areas are dropped by bats. In North America, bats are the primary predator of night-flying insects. A single bat can eat as many as 1000 mosquitoes in an hour. Bats also feed on beetles, leafhoppers, and moths, many of which feed on—and destroy—important food crops.

An abundance of bats seems to be an indicator of a well functioning ecosystem, and there is evidence that where bat populations have been disrupted, insect pest populations have risen. Worldwide, bats are endangered. Of the 45 species that inhabit the USA, six are endangered.

In North America, one of the main threats to bats is habitat loss resulting from urbanization, surface mining, municipal lake and reservoir construction (which flood roosting caves), and casual cave exploration (spelunking). Pesticides and wind farms positioned in their migratory pathways also strain bat populations. Another threat that seems to have the potential of decimating bat populations is White-Nose Syndrome. Apparently diseased bats with white muzzles were observed in a cave near Albany, NY, in 2006; dead bats were observed also. This syndrome seems to affect hibernating bats, and since it was first identified, sick, dying, and dead bats have been found in and around caves from New Hampshire to Tennessee. As many as 1 million bats have died. Federal and state laboratories are actively studying the syndrome. A newly discovered fungus (Geomyces destructans) that grows under cold conditions and infects bat skin may be associated, but the cause of the bat deaths is unknown. For more information see http://www.fws.gov/WhiteNoseSyndrome/index.html; verified 1 Aug. 2010.

Bat houses are a way of compensating for bat habitat loss. There are 10 North American species that nest in bat houses. So if you’re interested in supporting bat populations, there are lots of resources for bat houses on the internet, from commercially constructed ones to simple plans and information. A bat colony in your backyard will have the added benefits of reducing the number of insects in your yard and discouraging bats from roosting in your attic, where they don’t really want to live anyway.

This entry was posted on Tuesday, August 3rd, 2010 at 1:45 pm and is filed under Original Posts. You can follow any responses to this entry through the RSS 2.0 feed.
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31 Responses to “Batman: H. C. Heg On Bats”

  1. cheryl said:

    Thank you for educating us on the benefits of bats.
    A clarification on taxonomy: Both bats and rats are in the Class Mammalia; they diverge at the Order (rats are Rodentia and bats are Chiroptera).

    • H.C. Heg said:

      Thanks for the gentle correction, Cheryl. You’re of course quite right; I’m not sure what I was thinking. My apologies.

  2. sherlock david j said:

    Bats can become entangled in human hair as happened to a friend in North Wales UK when a bat became trapped and disorientated in her bedroom in the early morning and she and her partner had to extricate the panic stricken bat from their bed/duvet under which they’d been hiding-hoping thus it would go away as light seeped into the room-it seems to bear out the myth in that anyone who panics can it seems-in an enclosed space also panic the bat!

    • H.C. Heg said:

      Great story, David. It’s just this sort of event, as traumatic as it must have been, that as the carl jung would say “constellate” and thus makes more real our fears and imaginations.

  3. paseo said:

    Very interesting but I would have liked a mention of white nose syndrome which is decimating bat populations in northern New England. We have seen practically no bats in my area of rural Vermont this year. It’s really tragic.

    • H.C. Heg said:

      Good point. There’s not too much known about this syndrome except that it seems have to potential to devistate bat populations, as you say. And it’s not isolated in nothern new england. I’ve modified the article slightly and added a US Fish and Wildlife service website.

      Thanks for your comments.

  4. BONI HUBBARD said:

    I think we were raised in the same part of the upper mid-west!
    Street lamps don’t come on until 10:00 or later in the summertime!

    • H.C. Heg said:

      Dear Boni,

      It sure makes for great evenings and summers. Being elsewhere, I dearly miss it.

  5. zoe said:

    when I was young, oh so many years ago! we used to take my grandfathers flashlight (more like a lantern) and beam the light straight up into the sky and we could watch hundreds of bats flying amongst the tall poplar trees. we live in my grandparents house now, there are still some tall poplars, and we hear the bats squeaking in the night, but the numbers of them are greatly diminished from what I remember.

    • H.C. Heg said:

      Thanks for writing, Zoe. It sounds lovely.

  6. Lynn Araujo said:

    I enjoyed this essay on bats but I expected to read more about the decimation of the bat population from the white nose fungus. As a result of this disease the bat population in the northeast is being wiped out. I also used to enjoy watching bats at dusk as a child and then as a parent. Unfortunately here in CT there are few or no bats. I look for them in the summer sky but I have not seen a single bat in a few years. (And thus dramatically increased mosquitos) I wonder if building a bat house will bring them back – or if it is too late.
    Thank you for writing about this intriguing little creature.

    • H.C. Heg said:

      Thanks, Lynn. I’ve modified the article a little bit to include a some information on the white-nose syndrome and a Fish and Wildlife service website describing the syndrome and what’s known.

  7. Marilyn said:

    As a million people have probably already corrected you, rodents are mammals, too. They bear live young and suckle them.

    You’ve lost a lot of credibility on this one. From now on, I can not trust anything you write.

    • H.C. Heg said:

      Quite a few, yes. Thanks for writing, Marilyn. It was a dumb mistake; I’ll miss you as a reader.

  8. Margo Steinman said:

    This is an excellent article that corrects many of the false information about bats. But one of your statements is not true: “…but they are not rodents, they’re mammals.” Rodents are mammals; they have hair at some stage of their life cycle, mammary glands, and nurse their offspring. All mammals are live bearers except the Duck-Billed Platypus and Spiney Anteater, which lay eggs.

    Margo Steinman

    • H.C. Heg said:

      Thanks for the clarification, Margo. It’s to be hoped that humility and/or other admirable qualities are gained from stupid and embarrassing mistakes and make one a better person.

  9. Judy S said:

    I always was fascinated by watching the swallows disappear at dusk only to be seamlessly replaced by bats. This year we had very few bats in our small barn and bathouse, most likely due to the white nose syndrome. I truly hope they can recover!

    • H.C. Heg said:

      Dear Judy,

      Thanks for writing. I hope so too.

  10. Tom L.L. said:

    I am little concerned about your ramblings about bats. You said in your post, “Among other things we know about bats is that they may look like winged rats, but they’re not rodents; they’re mammals. They are far more closely related to humans than they are to rodents. They bear live offspring and suckle them.” This suggests that rodents are not mammals, which they are, in fact, 40% of all mammals on the earth are rodents, who also “bear live offspring and suckle them.”

    Although the hoary bat has a distance to imgrate, one of the hummingbird species that flies through the US to Canada from Central America and back again each year flies further, which is why I keep my hummingbird feeders out as late as November or December if we don’t get a lot of freezinf temperatures, in case a Rufous hummingbird got a late start and needs a food stop on its way south to Mexico.

    The CDC says that most bats do not have rabies. It has been found that Bats that have been tested only about 6% had rabies.

    If you have the right placement for them a Bat Box is a great addition to your back yard, because having bats are an asset to mosquito control. But the right placement to the Bat Box is essential. You may have never seen a bat in your neighborhood, but put up a Bat House and you will be surprised how quickly a colony is setup. My first rememberance of a bats was when I was at a friends house for a late night party as a child and discovered bats skimming the swimming pool for a drink.

    I lived in India for three years and one of the people I would be invited to visit off and on had a tree where the fox bats frequented. The looked huge when seen up in the tree and what was interesting when they took off in a group it was almost a flashback to the Wizard of Oz and the flying monkeys. It was quite a sight.

    Bye for now.
    Tom L.L.

    • H.C. Heg said:

      Thanks for your comments, Tom. I’d love to see the fox bats. As for rodents not being mammals, as penance I plan to have a pictue of a mother rat suckling her litter tatooed on the palm of my right hand.

  11. Michael said:

    I put up a bathouse on the west side of a large oak tree about 15 feet up 3 years ago and never had one visitor. Very disappointing. I live in zip 21620 northeat Maryland, Kent County on a large inlet to the Chesapeake Bay.

    • H.C. Heg said:

      Dear Michael,

      That sounds about right, but my understanding is that houses on poles become occupied more quickly than those on trees or buildings. You could perhaps move the house to a pole. Also, they should face SE to take advantage of morning sun and should be painted black to absorb sun. You could also check with a county ag agent in your area to see if he or she has any other recommendations.

  12. wendy said:

    Hello. Rodents are mammals

    • H.C. Heg said:

      Agreed. Apologies.

  13. Debby Brady said:

    Your article was wonderful, informative and supportive of a magnificant little creature. I’ve been an avid supporter of bats for many years. Thanks for publishing this article.

    • H.C. Heg said:

      Thank you for your kind comments, Brady.

  14. Steve McNew said:

    Please consider too the impact of White Nose Syndrome on bat populations, if illness in bats may be of interest. It is seriously reducing populations, particularly in the northeast, and is not yet well understood – spelunkers, that is casual cave tourists, are more a problem than real cavers, often National Speleological Society members, who take great care not to disturb any cave fauna. Thanks, Steve

    • H.C. Heg said:

      Dear Steve,

      I’ve modified the article a little with some information about white-nose syndrome and added a fish and wildlife service website with more extensive white-nose syndrome infomation. I’ve also added “casual” before “caver exploration” so as not to tar all cavers as spelunkers (now that is know the implication of the word).

      Thanks for writing.

  15. Fran H. said:

    How could leave out the fact that we’ve lost over 95% of bats in New England. The disease is decimating the entire eastern seaboard population of bats and you just neglected to mention it? Why? This essay should start with information about this holocaust.

  16. Karen Tweedy said:

    Excellent bat-cap, which inspires me to act on my long-planned installation of at least one bat house in my back yard. That might save me some of the money spent on cortisone cream for the mosquito bites!

  17. Suzanne Terryberry said:

    Very interesting information about Bats. I learned a lot. Thank you. We were in Katmandu, Napal, many years ago and were astonished to see trees on the main street, heavy-laden with huge Fruit Bats. As I recall they made a great deal of noise a we passed underneath in our little bicycle taxi. I want to put up a Bat-house in my Toronto garden. Any advice?

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