Behavioral Variation in Prey Odor Responses in Northern Pine Snake
Neonates and Adults
Kevin P.W. Smith, M. Rockwell Parker, and Walter F. Bien
Drexel University, Department of Biodiversity, Earth & Environmental Science, Philadelphia, PA, 19104
E-mail: KPS43@Drexel.edu
Introduction
The northern pine snake, Pituophis melanoleucus, is a state threatened fossorial species native to the New Jersey Pine Barrens. Squamate reptiles (snakes and lizards) rely heavily on chemosensory cues
to identify, locate, and choose between suitable prey items, but comparatively little research has focused on the chemical ecology of threatened squamate species. Such knowledge highlights ecologically
important aspects of their survival. Chemosensation is utilized by terrestrial vertebrates to discriminate among a diverse array of environmental chemical signals, including mate discovery and selection,
conspecific trailing, predator avoidance, and prey determination. We offered potential prey scents to adult and neonate Northern pine snakes and quantified their reactions in order to gain insight into their
potential prey preferences.
Results
Research Objectives
•  Quantify pine snake behaviors in reaction to various
potential prey scents.
•  Determine the presence or absence of an ontogenetic
shift in scent reaction behaviors.
•  Link reactions to prey preference.
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Neonate displays large bolus after
feeding. The bolus may persist for
up to a week.
Methods
Isolate chemosensory signals from potential prey
species with hexane swabs.
Offer swab in a random order to individual snake
neonates (n=19) and adults (n=13).
Follow Tongue Flick Attack Score (TFAS) protocol
(Cooper & Burghardt, 1990).
Record behaviors for 60 seconds and quantify
reaction.
Tested stimuli: hexane, water, white-footed mouse,
fence lizard, toad, grasshopper, cricket
1 mm
Neonate regurgitated sample.
Collected after a neonate was
isolated for 48 hours. Note long
(>1cm) dark hairs.
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Modified TFAS
•  Original Formula:
Tongue Flicks (TF) + Attack Latency
•  Does not adequately represent species that are slow
to strike.
•  Modified to include more characteristic behaviors:
•  TF + (Snout Rubs + Contact Latency) –
(Retreat + Retreat Latency)
OR
•  TF + (Positive Response) –
(Negative Response)
•  Renamed Tongue Flick Reaction Score (TFRS).
Field Observations
•  Behavioral experiments paired with field study.
•  Neonates (n=18) were radio-tracked over two years.
•  Neonate found with bolus during tracking and later
regurgitated a mat of hair.
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Figure Legend
Presence of Adult and Neonate bars when age classes differ.
Asterisk “*” denotes difference between age classes if present or among
stimuli if no difference associated with age.
Letters denote differences among stimuli within age class.
All α = 0.05.
Figures taken from (Smith et al. 2015, Chemoecology).
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Conclusions
Neonates and adults both show quantifiable interest
in rodents above all other scents.
Neonates displayed more active behaviors in
response to stimuli.
There is an ontogenetic shift in pine snake
behavioral reactions to the tested stimuli.
TFAS results to rodent scent correlate with field
observed predation evidence.
Acknowledgements
Special thanks to the NJ Air National Guard 177th Fighter Wing at Warren Grove Gunnery Range and
Emile DeVito and New Jersey Conservation Foundation for access to study sites and Kevin Redding at
Monell Chemical Senses Center for supplying rodent scents for tests. This project was sponsored
through the U.S. Army Medical Research Acquisition Activity (CA# CLN13-02-2-0045) with funding from
the Air National Guard Readiness Center. Thanks to the Betz Chair of Environmental Science, Drexel
University, for additional funding and logistical support. Also thanks to the NJDEP for advice, research
suggestions, and permit aid. This study is conducted under a NJDEP Special Scientific Collection permit
(# SC2014069) and an approved Drexel University IUCAC protocol (#18924).