Rattler! Did you know that the western diamondback rattlesnake Crotalus atrox can rattle its tail continuously for hours at frequencies approaching 90 Hz (90 times per sec)? This is twice as fast as a hummingbird’s wings.
● Nailing the Noise: The tail-end of the rattlesnake has a series of hollow “buttons” linked together, each made of keratin (found in our nails) and modified from the snake’s scales. At birth, there is only one pre-button, but each time a snake sheds its skin, another button emerges at the end. It’s a myth that one can tell the age of a rattlesnake from the number of buttons, because a snake may molt variably in a year and the buttons do break off with use.
● Sound production in animals, is energetically expensive. But the rattler is an evolutionary marvel, optimized for minimal cost and maximal efficiency (for the aficionados, only 0.015 micromoles ATP consumed per gram muscle per twitch). Surprisingly, energy use is independent of temperature and rate of rattling. There are six sets of tailshaker muscles, arranged at 45 degree angles to the axis of the tail. All six are active during rattling, with muscles on one side contracting while those on the other side relax. This out of phase contraction generates an oscillating motion seen in the gif image.
● Once you’ve heard a live rattler, you’ll never forget it, says Gnotic Pasta, who has plenty of snake stories to share. Do you have any cool facts or anecdotes about rattlers? Also check out Buddhini Samarasinghe scary post on Bite Reflex of a Snake here: http://goo.gl/Lz7oBN
▶ BBC Video (3:50 min) on high speed filming of the rattle (look behind the rattle for the forked tongue darting out!): Slow motion rattlesnake – Slo Mo #3 – Earth Unplugged
▶ Great basin rattlesnake Crotalus viridis lutosus filmed by our intrepid G plusser Gnotic Pasta : http://vimeo.com/64675533
▶ REF (old, but free): Structural correlates of speed and endurance in skeletal muscle: the rattlesnake tailshaker muscle. Schaeffer et al. http://jeb.biologists.org/content/199/2/351.long
H/T to Amy Robinson Sterling for sharing the gif that inspired this post (http://goo.gl/pzi4Yv).