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Showing posts from 2013

Lizard tricks: overcoming conflicting requirements of speed versus climbing ability by altering biomechanics of the lizard stride

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So recently I managed to publish a paper in the Journal of Experimental Biology about my dissertation work looking at the locomotion in Australia's biggest and baddest lizards the monitor lizards. I called it 'Lizard Tricks', not only cause I think they are doing something neat, but because I think what we see in these lizards would be a nice little engineering principal we could use in the design of robots or something else equally awesome. Ignoring for now that it took me over 6 years to figure this all out, I'd like to try and explain how I finally got to this point, and where we are with our understanding of locomotion in these beasts. All good studies should always start as simply as possible, and this is certainly where we began. In our earliest studies we compared the morphology of different species with their retreat site (Thompson et al. 2008). What we saw is that burrowing species tended to be different, from those that retreat into tree hollows, as sho

Jumping beans in Slow motion

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Between 2010 and 2012 I worked at the Rowland institute at Harvard university. Most of my time was spent researching the muscular dynamics of frog muscle, by building robotic frogs, but every now and then we liked to goof off scientifically. That chance came the one day when the head of my workgroup, Chris Richards, brought in a mexican jumping bean. Being from Australia, I had not seen one of these before, and that is sad. Cause they are friken awesome! The bean itself is the seed of a shrub, the genus Sebastiania . Inside this bean is growing the larve of a little brown moth ( Cydia deshaisiana ). The moth makes a hollow inside the bean, as it eats the bean from within. But what makes it amazing is that it is able to thermoregulate by moving the bean from hotter places (such as in the sun) to cooler shadier places. It does this by 'jumping' - hence the name. The actual mechanism of how this tiny moth can get the whole bean to jump is unknown, and would probably require so

Can the water dragon (Intellagama lesueurii) run on water?

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Can the water dragon (Intellagama  lesueurii) run on water?  I have long been impressed with the ability of the South American Basilisk lizard to run on water. There are plenty of videos of it on youtube, for example a short one here.  Its pretty amazing. Looking at this video alone shows as two important aspects of its locomotion, 1) it is able to lift the whole body out of the water, and 2) it is able to do so for quite long stretches (around 10-15m). This ability has been documented quite well by a series of papers by the group at Harvard University, particularly  Tonia Hsieh .  They have done some great work, including describing how smaller lizards are better able to support body weight than larger  lizards  , modelling 3D  forces  and recording 3D kinematics of the lizards  stride . Below is a gif showing some of the detailed kinematics of the lizard stride which i stole from George Lauders lab webpage.  (NOTE: just click on the gifs if they are not running)