Blind as a Bat: Certainly Not

And also not bad or beastly   

In the early 1980s in Finland I met a bat researcher who explained to me a device called the bat detector which works by changing the high frequencies of a bat’s cry, inaudible to humans, into audible lower frequencies. That device allows the researcher to look for the bats that s/he then knows are around. Sadly, that very bat researcher died in 1985 after being bitten by a bat that had transmitted the rabies virus to him. This was such a rare and isolated case in Finland that it made headlines and led to a hiatus in Finnish bat research. Despite the fact that bats can indeed harbour loads of viruses and other pathogens (but don’t get sick themselves) and may be pestered by parasitic flies of the families Nycteribiidae and Streblidae (because of the bats’ habit to be colonial, which involves close contact between individuals), they are, generally, of absolutely no danger to humans. Their life is an alien life that can last 40 years, a life in the dark, a quiet and secret life (except that of the thousands of fruit bats in Australia roosting in trees of parks and gardens). However, bats are absolutely fascinating mammals and earlier I already pointed out some of their remarkable reproductive adaptations with suspended pregnancies and (in some species) milk-producing “father bats” helping “mother bats” in parenting.

There are at least 1200 species of bats, which means 20% of all mammals can fly. Their sizes range from that of a bumblebee to that of a small dog but none of them is blind; a fossil Burrowing Bat from New Zealand is estimated to have weighed 40 kg. Their food habits are amazingly varied: some tropical species are important pollinators and visit flowers, others munch leaves or attack fruits; many species feast on insect pests like moths and beetles that fly around at night and some (the fish-eating bats) have even become accomplished piscivores. The notorious vampire bat of Central and South America is the only mammal that depends on blood for its diet, but although that may not be very nice, their habit of sharing a blood meal through a kiss with a colony member that hadn’t been able to find a food source shows an altruistic side. It is well known that bats form friendships with other bats and that bat orphans will be adopted by not even genetically closely related individuals of a colony. Bats are not blind but locate obstacles and food in the dark by echolocation (which I mentioned in an earlier blog).

Scientifically referred to as Chiroptera (from Greek “cheir” = hand and “pteron” = wing), bat wings are the result of a thin membrane between four of their fingers and are thus analogous to bird wings. Being able to fly, bats colonized far away islands like New Zealand, Hawaii and Galapagos, but being nocturnal only a handful species could survive in northern Finland despite the abundance of mosquitoes and other insects in the summer (only daylight in summer nights). The cold and long winters are no problem: many species enter into a state of torpor and hibernate in caves or other sheltered places. To rest and roost, most bats hang upside down, which required special adaptations with regard to their hind extremities, joints, muscles, tendons and circulatory system (a human would die if in an upside-down position for too long). An exception, as Daniel Riskin & Paul Racey could show in 2010, are sucker-foot bats like the Madagascar Myzopoda aurita: it clings head-up to leaves using specialized pads on its wrists and ankles.

I’m not aware of bats other than the large fruit-eating species being consumed as food by humans, but falsely accused of being a symbol of evil in many western societies, people should focus on the charming side of bats and revere them as harbingers of Good Luck and Prosperity as in some parts of China where bats often adorn wedding cards. Actually, in Europe killing a bat can result in hefty fines – that’s a start.

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2021.
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