Wild Things:
Life as We Know It
Dog faces, the history of laughter, snakes, and bird warning calls
- By Joseph Caputo, T.A. Frail, Megan Gambino, Ashley Luthern and Abigail Tucker
- Smithsonian magazine, August 2009
(David Hu / Georgia Tech)
Exactly how does a snake slither across the ground? Scientists long assumed that the reptile pushed against rocks and branches to move forward. But that theory lacks legs, according to a new study. After watching snakes wriggle up rough fabric surfaces or (less successfully) smooth surfaces, scientists from New York University and elsewhere say the secret is in the scales. The belly scales are oriented so that they snag on irregularities. By pushing parts of their belly down to take advantage of this friction, the snakes have enough leverage to speed ahead.
Additional Sources
"The mechanics of slithering locomotion," David L. Hu et al., PNAS, June 8, 2009.
"New nitrogen uptake strategy: specialized snow roots," Vladimir G. Onipchenko et al., Ecology Letters, June 4, 2009.
"Disambiguating the 'guilty look': Salient prompts to a familiar dog behaviour," Alexandra Horowitz, Behavioural Processes, July 2009.
"Mobbing calls signal predator category in a kin group-living bird species," Michael Griesser, Proceedings of the Royal Society B, May 27, 2009.
"Reconstructing the Evolution of Laughter in Great Apes and Humans," Marina Davila Ross et al., Current Biology, June 4, 2009.
Comments (3)
If snakes move over the ground, branches, etc. by pushing off of irregularities, how, pray tell, do they swim? Which they do quite readily?
Posted by Denise Mathews on August 29,2009 | 03:02 PM
I owned a German Shepherd for 13 years, and I swear she would look guilty and upset (even if I hadn't scolded her) and low and behind.. later I would find out she had gotten into a garbage can, or chewed up the newspaper, and even pooped in the closet! I believe she was smart enough to know the consequences of what she was doing at the time... and knew that I would be mad when I found out. : ) It was so cute when she looked "guilty" though.
Posted by Erica on August 21,2009 | 10:57 PM
I love snakes. And I find their anatomy fascinating. The whole belly scales catching on the objects and then used their stomach muscles to push off from it is quite amazing. Especially when they move so quickly (like a Black Racer)!
Posted by Erica on August 21,2009 | 10:53 PM