Biology Reference
In-Depth Information
in Chitwan, estimated the total number of that species in the park to be between 250 and 280
animals.
When possible, biologists strive to conduct longitudinal studies, that is, research programs
conducted over long enough time scales to yield insights that the typical field study, which
averages one to three years, often misses. In 1986, a Smithsonian Institution project that had
been focusing on tigers since 1972 embarked on population monitoring of the rhinos, which
has continued to this day with little interruption. These studies would allow us to track long-
term trends in the population and, most of all, to determine whether it is rebounding and has
responded to increased protection. So it was that, beginning in 1986, Vishnu, his fellow track-
ers, eighteen drivers, and I rode our elephants from one end of the park to the other to photo-
graph every rhino we saw. Each day we would spread out with five elephants to search for a
rhino. When we discovered a new individual or a familiar rhino that lacked a revealing set of
photographs, we would surround the subject. The other four elephants would usher the rhino
toward my sturdy mount, and my camera would capture its left side, right side, front, rear,
and horn. I made a special effort to note irregularities in the skin folds, knobs of extra skin,
cuts and scars, clipped tails, broken horns, odd pigmentation, and a variety of other charac-
teristics that would aid in recognition of individuals. Over time, we amassed a rhino register
with a distinctive name for each individual and personalized notes about where it lived, its
sex, the size of its horn, and, for females, the presence and birth date of a calf.
Male greater one-horned rhinoceros (
Rhinoceros unicornis
)
After three years of surveying the park, we found that the entire Chitwan population of
rhinos had grown from around 270 in 1975 to around 400 by 1988. The encouraging trend
showed that even very large, slow-breeding mammals can begin to recover from bouts of
near extinction when they are protected from poaching and a nucleus population of around
