Underappreciated reptiles can cope when the old rules change
By Susan Milius
CHOICES, CHOICESIn a lab test of mental flexibility, an Anolis lizard needs to select the round plastic lid of the correct color — which researchers may have switched — and then dislodge the lid to get a treat of freshly killed fly larva. Results from a new study suggest the lizards are smarter than most people think.Courtesy of Manuel Leal/Duke Univ.
Lizards everywhere may be scampering a little taller now that an Anolis species from tropical tree canopies has passed tests for behavioral flexibility.
“These guys are smarter than people say,” reports behavioral ecologist Manuel Leal of Duke University in Durham, N.C. Cognitive scientists have studied birds’ and mammals’ powers to solve unexpected problems and learn new rules, but research on lizard cognition has been limited.
Yet several Anolis evermanni lizards collected from Puerto Rico and brought into the lab coped with devices not seen in nature that were modeled on tests of avian brain power, Leal and Brian Powell, also of Duke, report in an upcoming issue of Biology Letters. In a series of tests, four out of six lizards figured out how to remove plastic lids firmly stuck on a food box and how to ignore lids with other colors introduced as possible distractors. Two lizards eventually were able to undo their previous training and choose the “wrong” color because researchers had reversed the rules.