1. Department of Anthropology, Texas A&M University
Anti-Predator Behaviors in Four Species of Nocturnal Strepsirrhine at the Duke Lemur Center
Cody Moser
Department of Anthropology, Texas A&M University
Abstract
At least one-third of known extant primate species exhibit nocturnal behavior, yet despite this fact, few projects have explored the interaction between their behaviors and environments. In this project, I build upon the relationship between nocturnal prosimians and their predators through the use of false predator models and playback experiments. Utilizing hawk calls, owl calls, and calls elicited by other predators found in their natural habitats, I attempted to elicit vocal and behavioral responses from the semi-free-ranging lemurs and lorises housed at the Duke Lemur Center in Durham, North Carolina. A model fossa (Cryptoprocta ferox) was placed in the enclosure during experiments when fossa vocalizations were played. These experiments expand upon an original experiment conducted on mouse lemurs in their natural habitat. I was able to increase the sample size from eight mouse lemurs (Microcebus murinus) to twenty-eight animals across five different species of strepsirrhine including; Microcebus murinus, Cheirogaleus medius, Daubentonia madagascariensis, Nycticebus pygmaeus, and Lemur catta. These behavioral data were supplemented with ultrasonic recordings and behavioral observations taken of the individuals in their free-range and colony-group enclosures at the Lemur Center. Preliminary data show a behavioral trend of crypsis in all nocturnal species tested, while diurnal L. catta exhibits an alternative trend. Further analyses of these data will attempt to elucidate roles of predator evasion and noctunality in primate diversity.
Cheirogaleus medius Artist: S. Dreilich
Nycticebus pygmaeus Artist: S. Dreilich
Score
Behavior +1
30 second stop
Stop + orientation toward stimuli
90 second stop
180 second stop -1
Run/Evade -2
Audible Vocalizations
Methods
Separate individuals from their social groups and isolate in room utilized for experiment.
Play vocalizations of natural predators to them after acclimation
Utilize predator models, in conjunction with vocalizations when available
Record behaviors and vocalizations
Record behaviors and vocalizations outside of experimentation, in living setting, to gather context on the responses given.
Research Questions
Is there a behavioral trend amongst nocturnal primates for the purpose of avoiding predation?
Is this trend independent of body size and the evolutionary history of these primates?
Are there ultrasonic vocalizations being emitted during incidences with predators and predator models?
Are the ultrasonic forms of communication we observe in multiple species of small-bodied primate utilized as a private channel in order to elude those who would like to eat them?
Score
Designation
0-1 point
Non-Cryptic
2 points
Semi-Cryptic
3 points
Cryptic
Legend: Scores were assigned to individuals to determine the level of crypsis exhibited in responses based on behaviors in the chart above. A B C
Distribution of Points Tallied for Each Species
Distribution of Points Tallied for Each Species
Distribution of Points Tallied for Each Species
A. Time each species spent in crypsis during bird call playbacks B. Time each species spent in crypsis during fossa vocalization playbacks C. Time each species spent in crypsis during combination fossa model, vocalization playbacks
Microcebus murinus (n=3) Cheirogaleus medius (n=7) Daubentonia madagascariensis (n=7) Nycticebus pygmaeus (n=4) Lemur catta (n=7)
Discussion
Behavior and calls were found to not be arbitrary to the experiment room.
Significant statistical separation was shown between Lemur catta and nocturnal species.
Crypsis was exhibited by Daubentonia madagascariensis as an antipredator strategy.
Ultrasonic communication was not utilized by individuals of any species during experimentation.
Antipredator strategies are independent of general body size in strepsirrhines and are probably associated more with nocturnality and degree of sociality.
Distribution of Points Tallied for Each Species
Legend: Average of behavioral scores for each species showing a nocturnal trend separate from that in Lemur catta.
Acknowledgments:
I would like to thank my advisor at Florida State University, Emily Lemmon, for mentoring me and assisting me in acquiring funding for this project. I would also like to thank Erin Ehmke and Anne Yoder for accommodating me and my project running at the Duke Lemur Center. David Brewer also deserves a special thank you for catching the lemurs for me and sitting in a dark room with me listening to hawks, fossa, and lemur calls for hours.
Daubentonia madagascariensis Artist: S. Dreilich