Can bats run? Part II of 'The bats that vamp... VAMPIRES'

Last year when I went to Belize to do field work we caught many vampire bats (Desmodus rotundus) which happen to be more cute and fascinating then they are scary.  I've written about these lovely bats before. 

As I prepare for another trip to Belize with the same great group of bat biologists I thought this might be a good time to write a bit about bats that don't just fly... but also WALK and even RUN*!  (*Technically we might define their gait as bounding not running but in any case (see below) they move quite quickly on the ground).

I don't study vampire bats so while I write here might sound like I am trying to convience readers that they are the coolest bats around (sure they might be...) there are many other fascinating bats.  The problem is that people tend to not LIKE vampires very much.  In many cases this is because some people are afraid of them for one reason or another probably mostly due to their diets.  However, perhaps by taking a closer look- people might learn to like them a bit more.

(Ho / AFP/Getty Images)

In that spirit- Bounding Vampires...

Bats are highly evolved to fly.  So much so that their body shapes including legs and feet have changed to accommodate flying and as a result they are generally bad at walking!  A bat that is on the ground will very often crawl up whatever it can find to gain some height before attempting to fly.  However, some bats need to crawl around because of what they eat.  Two particular species that are good at crawling around are the common vampire: Desmodus rotundus and the New Zealand short-tailed bat Mystacina tuberculata.  Desmodus as true vampire bat eats blood of animals which involves crawling around them to find a good spot to feast.  The New Zealand short-tailed bat on the otherhand is a leaf-litter forager but also lives in a place with no real native mammalian predators.

Wanting to understand more about how these bats are able to move on the ground as efficiently as they do Riskin et al. undertook a study on the biomechanics of both species.
(Riskin et al. 2006, Journal of Experimental Biology, 209, 1725-1736).

Stride cycles of Desmodus on a treadmill.  Figure 1 from Riskin et al. 2006.

This work resulted in the video you saw of vampires running on a treadmill (above) and a better understanding of bat kinematics during walking.  They were thus able to determine that the gait of the short-tailed bat is more of a 'walk' and that of the vampire is more like a 'bounding gait' as seen in other small mammals.

Below is another Figure from Riskin et al. 2006.  This illustrates stride frequency (how fast a foot is hitting the ground) plotted against how fast the bat is moving.  This figure compares the kinematics of the two species and also places them withing the different gait definitions.

Another great paper I'd also recommend is this one (citation below, clip to the right).

(Riskin & Hermanson 2005 Nature, 434. 292)

 To keep reading it go here.


















I hope that these cool behaviors/modes of locomotion illustrate how amazing these bats are and how much they can teach us about the evolution of locomotion.  Vampire bats have suffered a great deal of mistreatment and violence due to what people 'think' they know about them.  I hope that we can learn to live with these amazing bats, learn from them and marvel at how Natural Selection has led to what we see today in these beautiful,fascinating, intelligent and locomotion-wonders.

One way that bats are depicted... Focusing on the scary and 'horrible' impression that many people have...

Another way that bats are depicted.  Also- sorry that this is showing fruit bats... I would love to have put a picture of some book for kids illustrating how vampire bats are 'strange and wonderful' but they generally don't make the cover and if they do... well the images are almost always illustrating them as scary.  Below is one exception.