The campaign is not aimed at killing the gorillas, but counting their droppings for science. Baffled boffins were having trouble locating the gorillas in the rugged highlands, until they hit on the idea of getting some help from highly trained American hunting dogs.
A newly published study shows that sniffer dogs did a much better job at detecting scat, which must be counted to estimate the population size. The dogs do not pester the gorillas themselves. Counts of endangered wildlife in the area are crucial to conservation efforts.
The study, by the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) in Leipzig together with wildlife and working dog specialists from the United States, tracked reclusive Cross River gorillas (Gorilla gorilla diehli).
The animals inhabit rugged highland terrain on the border between Nigeria and Cameroon. A subspecies of the western gorilla (Gorilla gorilla), they are critically endangered and thought to number only 200 to 300 in the wild.
The researchers said their study was the first time that dogs had been tasked with locating gorilla faeces for genetic analysis in the challenging environment of an African tropical forest.
Writing in the London-based journal Royal Society Open Science, the researchers, led by Mimi Arandjelovic of MPI-EVA’s Department of Primatology, said they searched Kagwene Gorilla Sanctuary in December 2011 and Mone River Forest Reserve in January 2012, both in Cameroon.
Scat sample detection rates of dog-directed field teams were then compared with those of human-directed teams.
The dog-directed teams found, on average, about 0.9 to 1.4 scat samples daily, compared with 0.4 samples for the teams without dogs.
Genetic analyses of the 72 usable samples found by the dogs revealed that they had come from 19 individuals: four males and 15 females.
Hanns Hatt, a professor of cell physiology at Germany’s Ruhr University of Bochum and an olfactory expert, said he wasn’t surprised at the dogs’ performance.
“(Sniffer) dogs have about ten times more olfactory cells – 300 million – in their nose” than humans do, he remarked.
“And from the very first day of their lives, they constantly train their sense of smell,” he added. “That’s why they can pick up the scent of traces left days earlier, distinguish every person by body odour and detect the smallest amounts of narcotics or TNT.”
The researchers had one criticism of the US-based sniffer dogs’ work, though: the “considerable costs” of flying dogs in.
“To realize the full potential of dog-directed surveys and increase cost-effectiveness, we recommend basing dog-detection teams in the countries where they will operate,” they said.