Browsing by Author "FOX, SF"

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    EXPERIMENTAL-EVIDENCE THAT HIGH POPULATION FREQUENCIES OF LIZARD TAIL AUTOTOMY INDICATE INEFFICIENT PREDATION
    (1988) MEDEL, RG; JIMENEZ, JE; FOX, SF; JAKSIC, FM
    Frequency of autotomized tails in lizard populations has been taken as an indicator of predation pressure upon those populations. However, recent correlational evidence points to autotomy as reflecting lizards'' escape efficiencies and/or predators'' attack inefficiencies. We report experimental evidence on the relative inefficiencies of three predator species (a teiid, a snake, and a falcon) as autotomy-producing agents, and on the relative escape efficiencies of three congeneric lizard species under laboratory conditions. The falcon was the least inefficient lizard predator (100% of successful attacks) whereas the teiid and snake were more inefficient (10-20% of the lizards escaped by autotomizing their tail). Lizards that successfully escaped predation by the widely-foraging teiid had relatively longer tails than unsuccessful ones. No difference in this feature was detected between successful and unsuccessful lizards attacked by the sit-and-wait snake. All three lizard species were equally efficient at escaping the three predators through tail autotomy. Our observed differences of comparative inefficiencies of lizard predators give experimental support to assertions that tail-loss frequencies do not adequately serve as indices of presumed predatation pressure. High rates of tail-loss among lizard populaions could instead reflect attempts at predation by inefficient predators.