Phylogeny of Courtship and Male-male Combat Behavior in Snakes: An Updated Analysis

Coiling During Male-Male Combat in Snakes: Differences Between Vipers and Other Groups, and Between Constrictors and Non-Constrictors

“…We were therefore careful to include a video in the study only if we could confirm (or correct) the species identification, and only if it recorded combat. Combat can be distinguished from courtship in afrophidian snakes in that it usually includes attempts by the combatants to push down each other's raised heads (in non-lampropeltine snakes) or to pin each other's heads to the ground (in lampropeltines) (Senter, 2022). In contrast, courtship usually lacks such elements and includes a different suite of behavioral elements that usually includes chin-rubs and jerking of the head or body, often with the male performing such behaviors while his head moves along the dorsum of the female toward her anterior (Senter, 2022).…”

“…Combat can be distinguished from courtship in afrophidian snakes in that it usually includes attempts by the combatants to push down each other's raised heads (in non-lampropeltine snakes) or to pin each other's heads to the ground (in lampropeltines) (Senter, 2022). In contrast, courtship usually lacks such elements and includes a different suite of behavioral elements that usually includes chin-rubs and jerking of the head or body, often with the male performing such behaviors while his head moves along the dorsum of the female toward her anterior (Senter, 2022). As shown in Table 1, the footage included in the study comprises 100 instances of MMC in snakes of 49 species in six families: 29 instances in the family Viperidae, one instance in the family Loxocemidae, 12 instances in the family Pythonidae, 18 instances in the family Elapidae, one instance in the family Pseudoxyrhophiidae, and 39 instances in the family Colubridae.…”

“…In snakes of the clade Afrophidia (the clade that is phylogenetically bracketed by the boa and python clade and the clade Caenophidia-see Vidal et al, 2007), males engage in a combat ritual that often involves combatants coiling around each other and raising their foreparts, with each combatant attempting to push the other's foreparts down (Carpenter, 1977;Senter et al, 2014;Abu Baker et al, 2021;Senter, 2022). Detailed descriptions of male-male combat (MMC) have been published for numerous snake species (reviewed in Carpenter, 1977;Shine, 1978Shine, , 1994Senter et al, 2014;Abu Baker et al, 2021;Senter, 2022), but the number of loops in the coil is usually not reported.…”

Pelvic spur use during courtship and mating in the red-tailed boa Boa constrictor

“…girdles and vestigial hind limbs that are seen externally as pelvic spurs, which are probably a plesiomorphic character in the Alethinophidia (Stickel & Stickel, 1946;Palci et al, 2020;Senter, 2022). These pelvic spurs are generally larger in males than in females (Hoge, 1947;Slip & Shine, 1988;Shine & Slip, 1990;Hoefer et al, 2021).…”

“…Moreover, pelvic spurs have musculature, innervation, and vascularisation and can move autonomously (Hoge, 1947;Bellairs, 1950;Carpenter et al, 1978;1979). The pelvic spurs of boids and pythonids are known to be used by males during combat, courtship, and mating (Carpenter et al, 1978;Barker et al, 1979;Slip & Shine, 1988;Walsh & Murphy, 2003) and such use has been suggested as an ancestral character (Senter et al, 2014;Senter, 2022).…”