Sunday Mammalfest, Episode 5

What’s cooler than being cool? Ice cold.

And what’s cooler than being a bat? Being a megabat.

What are megabats? They are one of the two big divisions of bats, and also called ‘fruit bats’ or ‘flying foxes’. They are generally, though not always, larger than the microbats, who are however more numerous and widespread – microbats are found all over the world, while megabats are confined to the tropical jungle areas of Africa and Asia.

Other differences include their diets and sensory systems. With the exception of the Egyptian fruit bat, megabats do not have ‘echolocation’ (also known as ‘bat sonar’), instead relying more on their sense of smell. This is because they eat either fruit or nectar, and these are not nimble prey that dart around. Most microbats, by contrast, eat insects (or sometimes YOUR BLOOD), which do, and for this echolocation is very useful.

Another interesting thing about megabats is that they include the only double-breastfeeding animal species: in the Dayak fruit bat of Malaysia, both mothers and fathers naturally breastfeed their young. Now, this is possible for most mammals, including humans, but doesn’t happen naturally.

Nobody’s quite sure why this trait has appeared here. One possibility is that it’s evolutionarily useful to take the pressure of the mother; but then why would every other mammal species not have it? Another possibility is that their diet includes a lot of ‘phyto-oestrogens’, plant chemicals that mimic the effects of female hormones.

Another debate is about the relationship of megabats to microbats in general. The orthodox view is that they are two distinct lines of descent, starting from a single common ancestor (i.e. one order, with two sub-orders). Some people, however, think either that the division between the two lines isn’t so clear, with some microbat groups on the side of the megabats.

More interestingly (that’s debatable) some people have proposed that there is not a single common ancestor for all bats – that they in fact form two distinct orders, with the megabats being descended from primate-like ancestors (like lemurs or something) and the microbats being descended from mouse-like ancestors (like shrews or hedgehogs). So megabats would then not really be bats, as much as flying monkeys.

There’s a bit of evidence supporting this theory, but it seems that when more sophisticated genetic tests were carried out, the orthodoxy emerged victorious.

In conclusion, megabats are big, eat fruit and nectar, and sometimes lactate twice as much as you’d think.

5 Responses to “Sunday Mammalfest, Episode 5”

  1. DOMINO Says:

    So cute. So leathery.

  2. links for 2009-06-07 « Rumblegumption Says:

    […] Sunday Mammalfest, Episode 5 « Directionless Bones […]

  3. FilthyGrandeur Says:

    bats are so freakin awesome.

  4. Becky Talyn Says:

    I would love to get permission to use your bat picture. Is it a Dayak Fruit bat? I’ve been looking for a picture of them for a while that I can get permission to use. I teach biology classes, especially about reproduction, sexuality, and sometimes women’s/gender studies. If you could put me in touch with the photographer, I would be so appreciative!
    Becky

  5. Alderson Warm-Fork Says:

    Becky, I’m afraid I just picked these up off google. One of them is marked with ‘naturfoto.cz’ and the name Jan Sevcik, but that’s about all I know.


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