"We learned, to our surprise, that we have to house females near each other in order to trigger the reproductive cycle," he said. "We've had cases where two females were isolated, each with a mate, and neither of them cycled for years. Yet within a month of being housed in olfactory communication with other females, they both cycled and got pregnant." Glander speculates that females in the wild might use the scent of another female as a territorial or reassurance signal, but the phenomenon still remains mysterious.
To understand perhaps the biggest mystery -- how aye-ayes use their tapping to locate food -- Duke psychology professor Carl Erickson has spent the last seven years experimentally challenging the animals to perform feats of detection.
In his studies, he constructs puzzles consisting of mazes of insect-sized tunnels cut into the depths of pieces of lumber, then observes how the animals use their finger-tapping sonar to detect mealworms placed in the tunnels.
"Essentially, I've tried to understand what cues the aye-aye uses in finding prey beneath the wood surface," said Erickson. His first studies attempted to discover whether the animals' tapping was meant to disturb prey into tell-tale movement, or whether the animals were actually detecting subsurface hollows. He discovered that the animals were fascinated by the tunnels whether filled with mealworms or not, and whether they were hollow, stuffed with acoustical plastic foam, or even re-plugged with the same wood.
In an ultimate test, Erickson and then-undergraduate Luke Dollar decided
they would make detecting the subsurface features as hard as possible for the
aye-aye. First, they extracted plugs from wood blocks. Then, with two of the
plugs, they applied non-toxic school glue and let it dry before reinserting the
plugs. With two other plugs, they inserted the plugs coated with fresh glue.
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Contact: Dennis Meredith
Dennis@dukenews.duke.edu
(919) 681-8054
Duke University
8-Jul-1998