Asian elephant drawing by Mary Amaral
Our research group centers its activities on communication related to group dynamics and reproductive behavior in social mammals. The approach in my research group involves both proximate and ultimate components. Understanding behavior also is important in the conservation of species and ecosystems. For these combined interests, our focus has been on herbivores that act as ecosystem engineers in their respective habitats, namely beavers, manatees and elephants.
If you are interested in supporting our research, please see below.
All three of these mammals are important herbivores in their respective habitats. They modify the physical structure of their environment and alter the flow of energy and nutrients. As such, the behavioral ecology and conservation of these species are important concerns. Our studies strive to incorporate applications of our findings to improve the conservation and management of these species and their ecosystems.
Our research on communication among and across modalities explores the interaction of sender state and receiver condition on the structure and meaning of social signals. To date this research has examined scent mound signals in North American beaver (e.g. Schulte 1998) and urinary chemical signals in Asian elephants (Schulte & Rasmussen 1999). We are expanding this research to explore the influence of multiple signals within a single modality and the influence on the behavior of a receiver of simultaneous separate modality signals (multimodal communication).
Beavers are an interesting model system for studies on social communication and territorial behavior. Beavers are monogamous and may mate for life, living in extended family units prior to dispersal of offspring in their first, second or third year. Active primarily at night, beavers rely upon their sense of smell to navigate, locate food, detect predators and distinguish conspecifics. We are examining the interplay of chemosignals from different beaver 'glands'. Castor sacs release a urine-based suite of chemicals that function primarily in territorial signaling, although degrees of individual identity appear to be encoded. The viscous fluid from the anal glands is sexually dimorphic and apparently signals individuality (kin recognition). We are examining the sources of variability in these signals (e.g. diet and genetics) as well as the interaction between the two sources of signals in eliciting responses from receivers. In addition, we are studying the impact of beavers on the habitat in southern Georgia. Ms. Jessica Brzyski performed a study for her MSc (2005) on this topic, MSc thesis by J. Brzyski available here.
Social signals are highly prevalent among elephants but more abundant among the female-directed social groups compared to the much more solitary existence of adult males. In collaboration with Dr. L.E.L. (Bets) Rasmussen and Dr. Thomas Goodwin (Hendrix College), we have explored intrasexual and intersexual signals in elephant societies. Dr. Rasmussen and her colleagues have identified a sexual pheromone emitted in the urine by female Asian elephants to attract and stimulate conspecific males. Our current interests are many but include investigating the interplay among chemical, tactile and auditory signals among and between the sexes. The reproductive state of males and females is an extremely important component in the type of signal sent and the response elicited. In addition, we are studying the influence of forage selection on the social dynamics of matriarchal groups.
Unfortunately, Bets Rasmussen died in September 2006. We will miss Bets. Bruce Schulte and Tom Goodwin at Hendrix College, and students working with them, as well as many other collaborators, will continue to study elephant chemical ecology and behavioral development. See recent publications on CV page.
“Our understanding of mammalian pheromones is limited, owing to the complexity of mammalian life and the mammalian brain. Mammals integrate information received by their various senses, and this enormously complicates efforts to understand any specific signal. In addition, interpreting the reaction to a signal can be difficult. The reactions of mammals are not automatic, and their behavior is not necessarily reproducible. Sometimes a pheromone produces no obvious response in a mammal. Perhaps the animal has ignored the signal, or perhaps it has learned something for future use. In general, behavioral studies on mammalian pheromones are much more extensive than chemical research.”---William C. Agosta. 1994 Using Chemicals to Communicate. Journal of Chemical Education. 71: 242-246.
Our
research group at Georgia Southern in collaboration with Dr. Iske Larkin
at the University of Florida has been studying the behavior of the West
Indian manatee (Trichechus manatus) in captivity and in the wild.
We are examining the activity patterns in King's Bay (Crystal River, Florida)
and the sensory biology of manatees. We also are examining reproductive
hormones and the relationship to mating and social behavior. Ms Jennifer
Young completed her M. Sc. Thesis on the behavior of captive manatees and
obtained her Ph.D. at the University of Florida. This research was facilitated
by assistance from the Sirenia Project, each of the facilities housing manatees
in Florida, the Jane Smith Turner Foundation, the Eppley Foundation, and
Georgia Southern University. Manatee research was continued by Chifuyu Horikoshi
who worked on activity patterns and spatial
use in captive female manatees at Homosassa Springs Wildlife State Park;
she obtained her MSc in 2004. Mr. Ryan Berger spent 2005-6 studying manatees
in King's Bay and defended his MSc in 2007. His thesis is not yet available
on line.
We welcome additional graduate students for involvement in any of these research areas as well as undergraduates and professional collaborators. Contact Dr. Schulte by electronic mail at: bschulte@georgiasouthern.edu
The content of personal and other unofficial home pages is not sanctioned by Georgia Southern University and does not represent official information or opinions of the University. Bruce A. Schulte is solely responsible for the contents of this page.