McComb of the University of Sussex in the United Kingdom studied a population
of elephants orphaned from culling operations and placed in South Africa’s
Pilanesberg National Park. They found that the practice, which involves killing
older elephants and relocating young ones, has a strong effect on the behavior
and social knowledge of surviving animals, causing symptoms similar to those
experienced by people diagnosed with post-traumatic stress disorder.
South African wildlife officials used culling to control elephant populations
from the mid-1960s until 1995. To gauge the effects, Shannon and McComb
visited family groups in Pilanesberg and in Kenya’s Amboseli National Park,
where culling didn’t occur. They played recorded calls from elephants familiar and
unfamiliar to each, and of various ages. The Amboseli elephants responded as
expected: attentively bunched when they perceived high-level threats but relaxed
when the calls signaled low-level threats. Pilanesberg elephants responded
abnormally, showing no clear connection between threat level and reaction.
The behavioral ecologists attribute the abnormal responses to both the initial
trauma and the loss of role models that culling caused. “Fundamental aspects
of the elephant’s complex social behavior may be significantly altered in the long
term,” their study says. And because elephants transfer knowledge, this abnormal
behavior could be passed down for generations. —Lindsay N. Smith
