The neonatal spatial ecology of the Northern pinesnake (Pituophis melanoleucus) in the New Jersey pine barrens

Background/Question/Methods

Due to the cryptic and fossorial nature of northern pine snakes (Pituophis melanoleucus) there is a lack of data on their early life behavior and dispersal. An understanding of first season life history traits from hatching to ingress is particularly difficult to monitor. We used a combination of chemosensory assays and radio telemetry to investigate factors influencing neonate dispersal and habitat use.

External transmitters are not appropriate for semi-fossorial constrictors as they interfere with normal snake behaviors. We surgically implanted 18 P. melanoleucusneonates with small weight to mass transmitters and radio-tracked them after leaving their nests in September until hibernaculum ingress in November.  We monitored neonate activity daily and recorded environmental and behavioral data.

Snakes use their chemosensory system to collect chemical signals, around their environment. These chemical cues aid in prey determination and conspecific communication. Many pine snake females deposit clutches in the same nesting area, so neonates may gather chemical cues from siblings and non-sibling neonates. The integration of these cues and dispersal patterns has yet to be investigated. Neonates (n=15) were selected to run a y-maze test with the options of following a scent trail from a sibling and from a non-sibling conspecific neonate. 

Results/Conclusions

All neonates utilized habitat for foraging and thermoregulation within maximum distances of 34m to 450m of their nest. First year hibernacula were in close proximity to nest sites, and consistent distances between both years of study (2012: 33m to 255m, 2013: 30m to 225m). A compositional analysis is underway to elucidate habitat preference of neonates for northern pine snakes. While this is an upland species, neonates were regularly found in Atlantic white cedar swamps. Densely canopied areas dominated relocation habitats. We are also matching up these habitat selections with particular behaviors, such as ecdysis and feeding. We observed ten implanted neonates with boluses, and seven neonates with signs of ecdysis. Neonates were under cover 67% of relocations, so it is likely these other neonates were under cover during these events. Snakes will often use cover during digestion and shedding periods. Investigating optimal sites for these procedures will be beneficial with habitat conservation for this state threatened species.

Neonate tongue flick rates and movement rates are being analyzed for variations. Neonates followed sibling trails more often, though not significantly (p=0.059). The relatedness of a scent pathway may be a factor in dispersal, though not the dominant cue.