At the Zoo: Saving the Skittish Eld's
Deer
by Kasey McCracken
The
term endangered has become a much-used part of our vocabulary.
But while most of us readily cite tigers, gorillas, and pandas
as examples of endangered species, many other species are
consistently overlooked—perhaps because they lack the romantic
associations that people have with better-known mammals. Most
Americans would probably not mention deer when discussing
endangered species. After all, white-tailed deer are so abundant
in many places that we consider them a nuisance. However,
22 of the world's 40 deer species are listed as endangered
by the World Conservation Union (IUCN).
All three subspecies of the Eld's deer (Cervus eldi) fall into this category. Now found only in forested pockets of India, Myanmar (formerly Burma), Cambodia, Laos, and Vietnam, they once inhabited a much more extensive range, including much of Thailand. Eld's deer have reddish brown coats, and are about the size of white-tailed deer, but their antlers are remarkably different. Occurring seasonally on males, the antlers sweep from front to back in one continuous curve.
About 50 members of the Eld's deer subspecies found in Myanmar live at the Zoo's 3,100-acre Conservation and Research Center (CRC) in Front Royal, Virginia. The first three Eld's deer arrived at the center in 1976, and the animals have proved to be a challenge ever since. Eld's deer are extremely excitable and will run about erratically, bumping into any obstacles in their path at the least disturbance. Scientists at CRC initially believed that the best approach to managing Eld's deer was to allow them to remain in herds in large pastures on the center's grounds. But monitoring and caring for deer using this type of system was difficult, and the deer would frequently injure themselves during routine, essential procedures.
Associate Director for Conservation Chris Wemmer began to develop new husbandry techniques for managing the Eld's deer. He explored aspects of nutrition and mother-fawn interactions, and then initiated a program to hand-rear some of the fawns. These animals could be more carefully monitored, but they continued to react badly to disturbances.
Biotechnician Linwood Williamson believed that the best way to reduce the deers' self-destructive response to disturbances was to acclimate them to as many different sights and sounds as possible. He began to carry a noisy key ring with him at all times and, over time, made sure the animals saw and heard lawn mowers, tractors, and cars. Eventually even a radio playing in the barn 24 hours a day didn't bother the deer.
Williamson now trains the deer at CRC to enter the first open door they reach. Following his encouraging voice, they calmly walk onto a scale for routine weighing, enter their individual stalls, and even board a trailer. This allows researchers to work with the deer in ways that would not otherwise be possible. Veterinarians, for instance, can routinely vaccinate and draw blood from the animals without having to use an anesthetic.
The ability to work so closely with the deer at CRC has provided a unique opportunity to study their reproductive biology. Research Veterinarian Steve Monfort established the Endocrine Research Lab at CRC in 1987, and since then has been studying the Eld's deer's reproductive physiology. First he characterized the reproductive cycles of males and females by monitoring their hormone levels throughout the year. Monfort did this by analyzing hormone levels in the animals' urine, which Williamson easily collected by leading the deer into a specially designed stall that collected samples when the animals would urinate.
CRC biologists applied the information gained from these studies to an assisted-reproduction program. Monfort established that female deer begin estrus in late winter or early spring and that they enter anestrus, a period during which they are not sexually receptive, during the autumn months. Studies on males showed that they are essentially infertile from June to September. With this information, researchers could plan the best times for breeding animals and for collecting sperm from males for artificial insemination.
Due to the problems of shipping Eld's deer between institutions, it has previously been difficult to pair animals that are the least related. With the intensive management strategy and knowledge about reproductive biology developed at CRC by 1992, CRC biologists were ready to address this concern. They determined which animals within the U.S. population possessed the most valuable (under-represented) genetic information. The artificial insemination technique allowed suitable pairings to be arranged without transporting any animals.
The artificial insemination trial at CRC was highly successful, producing the largest number of pregnancies of an endangered species by artificial insemination. Nine of the 20 females artificially inseminated became pregnant. The seven surviving deer, considered a genetically sound population, were successfully shipped to the Singapore Zoo to begin a new breeding program there.
Meanwhile, CRC researchers are working with the Wildlife Sanctuaries Division of the Myanmar Forestry Ministry to improve wildlife protection measures and develop and implement a conservation program that includes a project for Eld's deer. Most of the Eld's deer found in Myanmar live in the Chatthin and Shwesettaw wildlife sanctuaries. Unfortunately, lack of funding and warden training in Myanmar's reserves mean that the staff there are ill-equipped to handle poaching and habitat encroachment. For example, when Bill McShea traveled to the Chatthin sanctuary in January 1995, he found that the staff there didn't even have vehicles to use for patrolling the sanctuary.
The CRC group has now established two teams of foresters and rangers to conduct ongoing field studies in the Chatthin sanctuary. In addition to gathering crucial information on the reserve's wildlife and habitat, CRC researchers aim to provide the Myanmar Forestry Ministry with training that will enable them to successfully manage Eld's deer in the wild.
Initial population censuses suggest that only about 2,000 Eld's deer remain in Myanmar—a 40-percent decline in the last 10 years. An ever-increasing human population on the periphery of the sanctuary brings more and more people in to collect fuelwood, thatch, and fruits. Those involved in the program recognize the urgency of stemming the decline of Eld's deer, but they also understand the need to balance this interest with those of the people living in communities surrounding the Chatthin sanctuary. They hope to accomplish this by encouraging local participation in the project and by providing environmental outreach programs.
In the meantime, studies of Eld's deer at CRC continue. Monfort hopes to begin in vitro fertilization trials this year. This technique of developing an embryo outside of the womb has far-reaching implications. The population of the Indian subspecies of Eld's deer has dwindled to less than 200, and biologists at CRC think that they could rapidly increase this number by implanting embryos from this subspecies into Zoo females of the subspecies found in Myanmar.
Despite being a reproductive biologist, Monfort is quick to say that technology alone will not save an endangered species. He recognizes that efforts aimed at improving the status of Eld's deer in the wild must combine lab research with the husbandry and field studies that have been carried out with the endangered CRC deer. Eld's deer are not an attention-grabbing species, but they uniquely contribute to the world's biological diversity—a diversity that researchers at CRC are ultimately trying to preserve.
(ZooGoer 25(3) 1996 Copyright 1996 Kasey McCracken. All rights reserved.)
