Fwd: [ABS] "Are bats walking or running?": article in Journal of Experimental Biology - check it out

["Mimi Pohl" <>]

Apologies for cross postings but this article about microbat energetics is fascinating! 

Cheers

Mimi

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Subject: [ABS] "Are bats walking or running?": article in Journal of Experimental Biology - check it out
To: "" <m("listserv.csu.edu.au","abs");">>

ARE BATS WALKING OR RUNNING?

Daniel Riskin is a self-confessed bat nut. He's mesmerised by these
remarkable mammals. But it's not just their ability to fly that intrigues
Riskin, `there's so much more to these animals' he says. Out of the more
than 1 100 known species, only a handful have opted for a terrestrial life
style, one being the common vampire bat. Riskin explains that these 30 g
vampires are incredibly manoeuvrable, capable of leaping several meters
from a standing start, but are they as agile on the ground? Riskin, Gerald
Carter and John Hermanson headed to the island of Trinidad to test the
vampires on terra firma (p. 1725).

Creeping along the ground, these tiny vampires feed on cattle after dark,
so Riskin and his colleagues staked out ranches, successfully capturing 5
of the mammals ready for their track tests. Returning to the lab, Riskin
introduced the bats to the treadmill and was amazed at how quickly they
took to crawling on it. Having filmed the animals as they walked, the team
found that the tiny creatures walked the same way as any other quadrupedal
creature.

Once the bats were confident on the treadmill, the team turned the speed up
and were amazed when the vampires burst into a strange bounding run with a
top speed of over 1.1 m s–1. They pushed off from the ground with their
mighty forelimbs bringing the hindlimbs foreword while in the air.
Returning to the ground on their hindlimbs, the bats reached forward with
their forelimbs ready to give the ground another shove. `It looks like a
running push up' says Riskin.

The vampires had come up with an unusual approach to terrestrial
locomotion, but were they unique? Riskin thought they might be until Bill
Schutt suggested he take a look at the endangered New Zealand short tailed
bat. Having evolved for millions of years free from predators, these tiny
bats are equally at home on the ground and in the air. But how would their
walk compare with the vampires'?

Teaming up with Stuart Parsons, Riskin and Schutt headed to a remote corner
of New Zealand's South Island to put the bats through their paces. But the
New Zealanders weren't as cooperative as the vampire bats. Although they
were much friendlier, it took them significantly longer to get to grips
with the moving treadmill. Once they had coaxed the New Zealand bats to
start moving, the team could see that their walk was very similar to the
vampire bat's, but even at their top speed, they never appeared to break
into a run.

Knowing that walkers recover most of the energy from a pendulum-like
stride, while the energetics of running are more like a bounce, the team
decided to measure the forces exerted by the bats' feet as they moved
across a force plate to see whether the tiny bats really were walking.
Amazingly, the energetics were more like those of a bouncing run, even at
the lowest speeds. The bats looked as if they were walking, but with a
runner's energetics.

Riskin admits that he is surprised that the bats have solved the same
problem in such different ways and adds that he hopes to continue working
with these intriguing creatures. `There's a whole lot more out there to do'
he says.

References


Riskin, D. K., Parsons, S., Schutt, Jr, W. A., Jr, Carter, G. G. and
Hermanson, J. W. (2006). Terrestrial locomotion of the New Zealand
short-tailed bat Mystacina tuberculata and the common vampire bat Desmodus
rotundus. J. Exp. Biol. 209,1725 -1736.[Abstract/Free Full Text]


Related articles in JEB:

Terrestrial locomotion of the New Zealand short-tailed bat Mystacina
tuberculata and the common vampire bat Desmodus rotundus
Daniel K. Riskin, Stuart Parsons, William A. Schutt, Jr, Gerald G. Carter,
and John W. Hermanson
JEB 2006 209: 1725-1736. [Abstract] [Full Text]

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