By Dave Andrews
Besides some obvious differences, such as a couple of horns and few thousand pounds, a rhino isn’t all that different from a human. At least, that is according to research conducted by Mason conservation scientist Elizabeth Freeman.
Freeman, an assistant professor in Mason’s New Century College, has been traveling to South Africa annually for the past three years to take a closer look at the lives of black rhinos. One aspect of her findings in particular may sound all too familiar to many of us humans—high stress levels tend to affect mating habits.
The focus of Freeman’s research is on the hormones and reproductive health of black rhinos. The worldwide population of the species has been rapidly diminishing in the past decades and especially in recent years. Freeman is doing all she can to help reverse that trend.
Freeman has been working alongside Rachel Santymire, director of the Davee Center for Epidemiology and Endocrinology at the Lincoln Park Zoo in Chicago. The two met at Mason while studying for a PhD in environmental science and public policy. Both women earned their doctoral degrees in 2005.
Freeman, Santymire, and their team of researchers are gathering data from the rhino population at the Addo Elephant National Park on the eastern Cape of South Africa. Addo was established in the 1930s in an effort to protect the elephant population, but more recently it has been introducing additional species into the park.
Initially, Freeman’s research focused on the elephant population within the park to determine whether female elephants experience menopause, just as humans do, by examining the elephants’ hormone levels. Soon after her arrival, park managers asked Freeman to begin measuring the rhinos’ hormone levels, as well.
Addo provides an ideal setting for data collection because the park is fenced into different sections, which expose the animals to different variables. Freeman is researching two sections of the park. One allows frequent visits from tourists, features several human-made water holes, and has predators such as lions and hyenas. The other section allows fewer tourists, relies more heavily on natural water resources, and has no large predators. Together, the two sections contain about 45 black rhinos.
The preliminary research shows that rhinos living in the more demanding, stressful environment in which they must tolerate potential human disturbances and evade frequent attacks have a higher level of stress hormones and are therefore less likely to reproduce.
Much of the hard data are obtained by examining the rhino feces, but matching each rhino to its excrement is a challenge because of the rhinos’ elusive nature toward humans. To overcome that obstacle, Freeman placed infrared cameras throughout the park that begin recording once they sense movement. The cameras are noninvasive and help the researchers match each rhino to its feces and identify their behavioral patterns. In addition, the hidden cameras enabled the researchers to observe the rhinos’ sleeping habits, something no team has studied before.
Freeman says that this is one of the most comprehensive studies on the black rhinos ever conducted. Freeman and Santymire will present a portion of their findings later this fall at the International Elephant and Rhino Conservation and Research Symposium in Rotterdam, The Netherlands.
Ultimately, Freeman’s goal is to help create a resurgence in the world’s rhino population. In the early 1990s, habitat destruction and widespread poaching nearly drove the species into extinction. Slowly, the numbers of rhinos are rising but not at the rate Freeman and her colleagues would like to see.
“It’s scary how dramatically poaching rates have risen in South Africa,” says Freeman. She explains that in 2010, about 350 rhinos were poached and considering that the worldwide population of rhinos is about 4,240, 350 represents a significant loss.
As the black rhino research project moves into its fourth year, Freeman has also partnered with Cody Edwards, director of the Science and Math Accelerator in the College of Science. Edwards’s background in molecular phylogenetics and conservation genetics will help the researchers validate their field methods and determine the genetic health of these isolated populations of black rhinos.
The park’s wildlife managers will use the study’s findings to improve the rhinos’ breeding rate and determine the most effective way to conserve and relocate the animals in the future. The researchers acknowledge that the black rhino will forever be a slowly repopulating species, but by having a better understanding of the biological and environmental factors that affect their mating habits and stress levels, they hope the animals will soon reach their full reproductive potential.
Most of the rhino research thus far has been funded by Mason and the Lincoln Park Zoo. Both Freeman and Santymire are optimistic that through their efforts, more grants will be awarded and the research program can be expanded to other regions of Africa.