All over the world, wild elephant populations are decreasing due to a variety of factors. As this continues to happen, the wild elephants’ survival depends on knowledge acquired through research on elephants in settings such as zoos. Since these elephants are more accustomed to interaction with people, they are immensely valuable to research efforts. They are more approachable and cooperative than their wild counterparts and give researchers constant access to biological samples. Studies also can be enhanced with the addition of information readily available from keeper staff who have in-depth, first-hand observations of elephants.
Additionally, the North American African elephant population is not self-sustaining. This is due mainly to prolonged lack of reproduction until recently. Only 70% of captive female elephants are of breeding age and a portion of these do not have normal reproductive cycles, making it very hard for them to breed.
To bolster the North American African elephant population through successful breeding and to understand all possible causes of elephant population declines in the wild, the elephant community is learning all that it can about every aspect of elephant biology. Topics of research are varied and include nutrition, non-vocal communication, male elephant fertility, female elephant reproductive biology, behavioral studies, and disease and genetic research. Knowledge gained from research can be applied to help ease the plight of wild elephant populations all over the world.
The Maryland Zoo in Baltimore has a history of actively collaborating in conservation and research studies and seeks participation in projects that fit into the Zoo’s overall commitment to furthering animal knowledge. The Zoo’s elephant keepers are proud that our elephants are helping other elephants by participating in several research projects. Regular blood samples are collected from them to track general health, as well as to monitor their reproductive cycles. This makes them ideal candidates for many non-invasive studies. Below are some of the projects with which the Zoo has been involved.
Female elephants communicate when they are ready to breed through a variety of chemical and behavioral signals, many of which are not known or understood. This study aimed to learn more about breeding behavior by analyzing chemical signals and sexually-specific responses. Keepers collected urine at specific points during the elephants’ reproductive hormone cycles and mailed the samples to the lab.
The urine samples were put into the exhibits of male elephants, and their responses were observed. Researchers found that the males could tell the difference between urine collected when the females were ovulating and urine collected when they were not. These conclusions and extensive chemical analysis of the urine may lead to the development of a safe and effective chemical deterrent to keep elephants away from human-inhabited areas.
This project examined behavioral factors and social dynamics of elephants in zoos around the country to learn more about what influences reproductive hormone activity. Do elephants with normal reproductive cycles behave or react differently than those with irregular cycles? Does social hierarchy affect hormone activity?
Dolly and Anna’s behaviors and interactions were observed, and keepers filled out behavioral questionnaires. Urine from bull elephants in musth (a period of heightened sexual readiness) was also introduced into the exhibit to investigate the females’ reactions to this novel stimulus. Conclusions from this study may lead to a better understanding of how social dynamics affect the breeding cycles of elephants and how we can better manage them to further enhance elephant health.
It is unknown whether wild elephants undergo periods in which they don’t experience normal reproductive cycles. Once this mystery is solved, scientists can ascertain whether the same factors affect the ovarian activity of both zoo and wild elephant populations. This, in turn, should allow for more successful breeding efforts and help to better understand reproduction in wild populations.
The goal of this study was to develop accurate monitoring kits to check ovarian and adrenal gland activity by testing feces of wild elephants. The adrenal gland is important to reproductive biology because it is associated with the body’s response to stress, which may suppress fertility. Samples of blood and feces were collected from Dolly and Anna for six months and were used to calibrate and check the validity of the developing test kit.
Anna was also used for a part of the study in which her adrenal gland was directly stimulated by cortisol, a test done in humans regularly. This enabled researchers to compare the cortisol excreted with the known quantity circulating in the body. This information was vital to further improving the monitoring kit and to making certain it was functioning properly.
This will be a significant advance in research. It will allow field scientists to monitor the hormones of wild elephants without disturbing their daily lives and without requiring them to anesthetize the elephants and draw samples of their blood. This will allow scientists to gather information without performing an invasive procedure that could be dangerous to the wild elephants
Elephants are generally thought to be the only land animals that produce infrasound, sound whose wave frequency is too low (under 15-20 hertz) to be heard by humans. In this project, a special microphone able to pick up low frequencies was used to record Dolly and Anna during interactions with keepers. These recordings were used as a baseline to compare the recordings of some other mammals to see if they also produced infrasound. Pygmy hippos, giraffes, and white rhinos were all tested, but no evidence of infrasound was found.
Naturally, each project generates many new and important questions about elephants. Stay tuned to learn more about the ongoing research in the elephant community and how elephants at The Maryland Zoo in Baltimore are helping their wild counterparts.
The elephant section of this site was made possible by a gift from C.J. Miller LLC