Meeting Abstract
In animals, meal size is determined by numerous endocrinological and neurological factors, and in juveniles of species with post-natal parental care, meal size is in part regulated by the parental guidance or direct provisioning. However, in animals that have very limited or complete lack of post-natal parental provisioning, it is assumed that meal size is determined primarily by intrinsic factors and experience. For gape limited predators, such as snakes, this approach may lead to costly mistakes in attempting to capture, ingest, and digest large prey. In this study, we explored whether and how juvenile snakes determine prey size. We observed feeding records from juvenile Texas rat snakes (Pantherophis [Elaphe] obsoletus lindheimeri) fed small, medium and large prey, and measured the effect of prey size on search, approach, contact, and ingestion behaviors. Our results show that juvenile snakes spend equal amount of time searching and approaching prey regardless of relative prey size, but spend more time in direct contact with relatively large prey. Furthermore, while there was no difference between large, medium and small prey juvenile in number of tongue flicks, snakes spent more time chin rubbing and biting prey prior to attempting to ingest them. Our data suggest that while snakes rely on chemo-sensory and possibly visual cues to assess preference and locate prey, snakes may rely on tactile cues to determine size of prey in close proximity. Because juvenile snakes will attempt to handle and ingest prey that are too large to consume, we propose that handling time and stress may play important roles in shaping snake diets during early experiences.
