A behavioral analysis of male-male combat in free-ranging Eastern Massasauga rattlesnakes (Sistrurus catenatus)
Perelman, Zander E.
zanderp2@illinois.edu
Department of Biological Sciences
Sam Houston State University
Huntsville, Texas USA
Illinois Natural History Survey
University of Illinois Urbana-Champaign
Champaign, Illinois USA
Lutterschmidt, William I.
Department of Biological Sciences
Sam Houston State University
Huntsville, Texas USA
Reinert, Howard K.
Department of Biology
The College of New Jersey
Ewing, New Jersey USA
Although male-male combat has been documented for numerous snake species, combat events and behaviors are not often quantified or analyzed beyond simple descriptions. Combat events between snakes within the genus Sistrurus are rarely observed, and only one previous report has offered detailed descriptions and analyses of behaviors. Observation of snake combat behavior is an opportunistic event, and consequently, detailed behavioral descriptions and analyses as performed here are particularly rare under natural field conditions. We discuss a combat event between two free-ranging male Eastern Massasauga (Sistrurus catenatus) in western Pennsylvania. A video recording of the event was used to describe and quantify the behaviors. Observations of male-male combat were possible because of the close monitoring of a radio-tracked female Eastern Massasauga (MS-01). While tracking MS-01, we first encountered male MS-04 close to her (0.5 m) on 30 July 2021. Male MS-04 accompanied MS-01 until he engaged in combat with another male (MS-05) on 1 August 2021. On 2 August, MS-05 ousted MS-04 and successfully copulated with MS-01. Observing the full progression of behaviors allowed us to describe the combat event accurately and subsequently analyze and compare the combat behaviors displayed by MS-04 and MS-05 with respect to the outcome of the combat; MS-05 winning and copulating with MS-01. Such social behaviors have clear implications for reproductive success at individual and species levels. Detailed analyses of combat behavior may prove useful in an evolutionary context by allowing for potential phylogenetic comparisons regarding reproductive success and fitness.