Small herds of Przewalski horses in the Chernobyl nuclear disaster area in the Ukraine are dwindling, perhaps due to human predation, according to a Chernobyl biology expert.

Poverty-stricken people living close to the herds are suspected of poaching the horses for their meat, either to eat for themselves or to sell, the BBC reported in late July. But this is just one explanation, Timothy Mousseau, PhD, professor of biological sciences and associate vice president for research at the University of South Carolina, said. What’s really happening to these critically endangered animals–estimated at only 30-40 individuals, down from 65 in 2003–is yet to be confirmed.

"Details are scant," Mousseau said. Other hypotheses include wolf attacks or the effects of possible radiation the horses consume while grazing within the actual "exclusion zone"–the area within a 19-mile radius of the Chernobyl nuclear reactor that exploded in 1986. However, wolf numbers seem to be low–especially in the exclusion zone, Mousseau says–and no known studies have been carried out to show how radiation has affected horse health there.

Should the poaching explanation prove to be correct, consuming such horsemeat would most likely present a significant risk to human health as well, since the horses have been grazing in the most contaminated areas, Mousseau added