[Annelida] Rhythmically turtled earthworms
(by g.read from niwa.co.nz)
Tue Oct 23 00:51:07 EST 2007
FYI. Not new but certainly curious.
"The Wood Turtle has been observed in both captive and wild situations
to use an unusual technique known as earthworm stomping to drive
earthworms out of the ground, which are then consumed by the hungry
turtle. The turtle accomplishes this by stomping on the ground with a
foreleg or the underside of the plastron in a rhythmic and repeated
pattern. The intensity of this stomping can grow to the point where the
thumping is audible from several meters away. Typically a turtle begins
this behavior by stomping and digging several times with a single
foreleg, alternating to the other foreleg, occasionally raising its body
and then driving its plastron against the ground. It then stops, moves
forward slightly, and begins the behavior again. This activity will
continue until an earthworm surfaces and is devoured. Stomping sessions
can last for considerable periods of time: studies from Pennsylvania
have reported sessions lasting more than 15 minutes, and incredibly in
one recorded instance the session lasted for more than 4 hours
(Kaufmann, 1989). The activity is quite profitable for the turtle; with
worm capture rates averaging 2.4 worms per hour (Kaufmann, 1989).
Earthworm stomping turtles are thought to be exploiting a natural
tendency by earthworms to come up to the surface when they sense
rhythmic vibrations in the ground, such as those generated during rain
Kaufmann, J.H. 1986. Stomping for earthworms by Wood Turtles, Clemmys
insculpta: a newly discovered foraging technique. Copeia 1986(4): 1001-1004.
Kaufmann, J.H. 1989. The wood turtle stomp. Natural History 8: 8-10.
Geoff Read <g.read from niwa.co.nz>
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