Animal athletics: the benefits of being short
Could your dog win an Olympic race? Scientists at the University of California, Santa Cruz, USA, have been comparing limb shape with athletic performance in a range of animals to determine who makes the best athlete.
At the Society for Experimental Biology meeting on Tuesday 3 April, Dr Terrie Williams of the University of California will present her findings on the energetics of marine, semi-aquatic and terrestrial animal movement. By training Corgis and otters to run on treadmills Dr Williams has been studying how limb shape affects athletic performance and the energetics of running and swimming.
“The study is relevant to questions such as why triathlete competitions are more difficult to compete in than single events,” says Dr Williams. “Why is it so difficult to perform equally well in different sports? We can equate animal athletics with human triathletes who are trying to perform beyond the design of their body, given that humans are better adapted to running than swimming.”
In animals, morphological compromises such as shorter limbs appear necessary to adapt to different media, such as air and water. While a dog’s shape may be specialised to enable it to run efficiently on land, otters limbs are shorter to enhance swimming ability while retaining a reduced capacity to run. By comparing specialised vs non-specialised body shapes, Dr Williams has worked out how locomotion and shape affects performance and energetics.
“Corgis run remarkably fast for their short limbs, because they have a long reach and large angle of movement in the limbs,” says Dr Williams. “Their length of step is effectively the same as a larger animal of similar body mass. Otters, with a similar limb size, run at lower speeds but make better swimmers because of greater flexibility in their backs.”
So what are the benefits of being short? “It allows for streamlining as a swimmer,” says Dr Williams. “The enhanced aquatic movement in an otter is worth the sacrifice of poorer running ability.”◊ A public release from Society for Experimental Biology in April 2001, viewed from Biology-Online.org.
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