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One of our cooters ‘little girl’ learning how to walk in a sustained manner on a dog treadmill. Turtles are trained for 2-3 weeks prior to experimental strain recordings from their hindlimb muscles and bones. River cooters are very easy to train and generally have a friendly disposition. They make a great model for testing hypotheses about hindlimb function because they are limited to a walking gait, and walk slow and steady.

[video: 1080p, compressed from streaming]

Turtle Treadmill Training

Dr. Butcher teaches a Comparative Biomechanics course in the Spring that makes use of innovative and engaging laboratory exercise. One of which is based in training practices of the Ancient Greek Olympians. This exercise involves jumping with hand weights, originally called ‘halteres’, before the modern dumbbells. Ancient greeks observed that athletes could jump longer distances with weights in their hands than without, although they did not have an understanding of the mechanics involved. I developed this lab with my mentor, John Bertram (Univ. of Calgary), and use this exercise do teach students about Newtons Three Laws of Motions. The fundamental mechanics of jumping and how distance can be improved with weights is a simple, yet elegant demonstration of each Law. The videos are of one of my students, Joe Crook, exemplifying the effect of using halteres. For specific information on how to run the laboratory exercise and explanations of the 6 major mechanical principles involved see Butcher & Bertram 2004. PDF  

[videos: 1080p, compressed from streaming]

Jumping With Hand Weights

We use opossums to answer a number a scientific questions related to the biomechanics of limb systems and how loading is influenced by limb posture. Opossums display a crouched posture like many small mammals. For a number of years Rick Blob (Clemson) and I have been interested in the evolution of limb bone loading and design. We have done locomotor (treadmill) bone strain studies on species from a several taxa including: turtles, lizards and opossums. This is a video from one of our femur strain recording trials. Opossums can only walk and trot because of the retention of epipubic bones and the arrange of their abdominal muscles attaching to these bones. The video is exported as a large AVI file.

Opossums On Treadmills

We studied tail structure and function in Caluromys derbianus, a highly arboreal  opossum that never inhabits the forest floor, unlike several other species found in this region. This is a video of a field release of C. derbianus by our colleagues at the Tirimbina Biological Reserve. They are performing capture/recapture studies with these opossums as part several mammalian conservation projects in the neo-tropical rainforests of Costa Rica. The tail of C. derbinaus is nearly 2x the head-body length and they use it for balance during running and leaping (seen here). Additionally, they use the tail as a fifth appendage for other arboreal maneuvering, such as suspension. The video has been compressed from a larger AVI file.

Caluromys in the wild

We used armadillos to further answer questions about how limb bone loading is influenced by limb posture. Much like opossums, armadillos are primitive mammals  that display a crouched posture, and are a good model species to determine the evolutionary timing of changes in bone loading between sprawling reptiles and upright cursorial mammals. This is a video from one of our femur strain recording trials (individual A01) done in Rick Blob’s lab. Armadillos seem to prefer a walk-run gait on the treadmill. The video is exported as a large AVI file.

Armadillos On Treadmills