Defensive Mechanisms of Neotropical Salamanders with an Experimental Analysis of Immobility and the Effect of Temperature on Immobility

Publication Type:Journal Article
Year of Publication:1976
Authors:C. Dodd, Jr., K, Brodie, Jr., ED
Date Published:1976
ISBN Number:00180831
Keywords:Corvidae, Cyanocitta, Cyanocitta cristata, Garrulus, Garrulus glandarius
Abstract:Antipredator mechanisms of 19 species of Neotropical salamanders were studied. Defensive postures generally fell into eight categories: body arched, body elevated, body coiled, limbs extended, limbs clasped, tail arched, tail elevated, and tail undulated. Individual salamanders often used several of the above postures simultaneously. Flipping falls into three categories: coil-uncoil, running, and serpentine. Coil-uncoil flipping is most prominent in the Central American species of Chiropterotriton and the genus Oedipina while running flipping is most prominent in Mexican Chiropterotriton. Serpentine flipping was observed only in Oedipina uniformis. Although listed as coil-uncoil, the flipping of the genera Bolitoglossa and Pseudoeurycea remains to be analyzed. Between 65% and 100% of the individuals of each species became immobile when initially contacted in the field. Immobility was also timed in both field and laboratory when the salamander was dropped 10 cm, rolled onto its back, and from time of righting after being rolled until first movement. Bolitoglossa subpalmata, Chiropterotriton dimidiatus, and Chiropterotriton multidentatus were tested at 4°, 12°, and 20°C to study the effect of temperature on immobility. Adult and juvenile B. subpalmata remained immobile longer at lower temperatures than at higher temperatures while young remained immobile longest at 12°C. Both species of Chiropterotriton remained immobile longest at temperature extremes although only in C. multidentatus not in breeding condition was this relationship significant. At 4°C large B. subpalmata remained immobile longer than small animals. There was no such relationship at 12° or 20°C or for any temperature for C. multidentatus. Massed trials testing indicated neither an increase nor a decrease in duration of immobility for any size class of B. subpalmata, C. dimidiatus, or C. multidentatus at any temperature. Trials indicated that salamanders that remain immobile when faced by a predator survive more often than those that move. Predator reaction to B. subpalmata and C. multidentatus confirmed that salamanders do posture and/or flip to escape predation. Blue jays (Cyanocitta cristata) avoided B. subpalmata after contact, therefore, indicating noxious properties in this salamander. The importance of noxiousness, immobility, morphology, postures, behavioral ontogenetic changes, coloration, and environmental parameters to Neotropical salamanders is discussed.
Short Title:Herpetologica
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith