In June 2006, "British Science Weekly" reported that Cleve Hicks and colleagues from the University of Amsterdam had completed a year-long hunt for these apes during which they were able to observe the creatures a total of 20 full hours. Hicks reported, "I see nothing gorilla about them. The females definitely have a chimp's sex swellings, they pant-hoot and tree-drum, and so on". DNA samples recovered from feces also reaffirmed the classification of these apes in the chimp subspecies "Pan troglodytes schweinfurthii".