Feeding behavior varies based upon prey defenses in the ground snake (Squamata: Serpentes: Sonora episcopa)

Abstract

Predators with diverse diets can use generalized feeding behavior to consume different prey types or can alter behavior based upon the functional demands of each prey type. Prey choice and feeding behavior are especially important for limbless, gape-limited predators, such as snakes, because the head must capture, subdue, and ingest prey. Although previous studies have described how snakes feed on dangerous prey, these studies have not compared how behaviors might vary with different prey types. We analyzed the feeding behavior of ground snakes (Sonora episcopa) that were fed scorpions, spiders, and centipedes. Ground snakes successfully consumed each prey type using different behaviors for each prey. To capture prey, snakes used the unusual behavior of pinning prey with the ventral surface of the head with a closed mouth strike before biting. Snakes grasped and envenomated scorpions in all trials, and this behavior lasted significantly longer for scorpions than for spiders. During envenomation, snakes used their body to pin the telson of the scorpion to reduce the likelihood of being stung. Rather than using body restraint to subdue spiders, the snakes often dragged spiders across the substrate with the mandible. Scorpions repeatedly pinched and stung snakes during feeding and snakes used body restraint to subdue this prey significantly more often than spiders. Our study revealed that ground snakes alter feeding behavior based upon prey defenses and use novel prey capture and handling behaviors to subdue prey, suggesting there is yet unappreciated diversity of feeding behavior in snakes allowing them to exploit dangerous arthropod prey.