[1] Max Planck Inst Evolutionary Anthropol, Deutsch Pl 6, D-04103 Leipzig, Germany
[2] German Ctr Integrat Biodivers Res iDiv, Halle Leipzig Jena, D-04103 Leipzig, Germany
[3] Wild Chimpanzee Fdn, Deutsch Pl 6, D-04103 Leipzig, Germany
[4] West Chester Univ, Dept Anthropol & Sociol, W Chester, PA 19382 USA
[5] West Chester Univ, Dept Psychol, W Chester, PA 19382 USA
[6] Kwame Nkrumah Univ Sci & Technol, Fac Renewable Nat Resources, Dept Wildlife & Range Management, Kumasi, Ghana
[7] Korup Natl Pk, Korup Rainforest Conservat Soc, POB 36, Mundemba, Sw Region, Cameroon
[8] Wildlife Conservat Soc, 2300 Southern Blvd, Bronx, NY 10460 USA
[9] Chimbo Fdn, Amstel 49, NL-1011 PW Amsterdam, Netherlands
[10] Aspinall Fdn, Port Lympne Wild Anim Pk, Hythe, Kent, England
[11] Cornell Univ, Elephant Listening Project, Bioacoust Res Program, Cornell Lab Ornithol, 159 Sapsucker Woods Rd, Ithaca, NY 14850 USA
[12] Royal Zool Soc Antwerp, Ctr Res & Conservat, B-2018 Antwerp, Belgium
[13] Univ Stirling, Sch Nat Sci, Stirling FK9 4LA, Scotland
[14] Agence Natl Parcs Nationaux, Batterie 4,BP20379, Libreville, Gabon
[15] Inst Rech Ecol Trop, Libreville, Gabon
[16] Royal Holloway Univ London, Egham Hill, Egham TW20 0EX, Surrey, England
[17] Royal Soc Protect Birds, Potton Rd, Sandy SG19 2DL, Beds, England
[18] Univ Cambridge, Pembroke St, Cambridge CB2 3QG, England
[19] Arizona State Univ, Sch Human Evolut & Social Change, 900 Cady Mall, Tempe, AZ 85281 USA
[20] Arizona State Univ, Inst Human Origins, 900 Cady Mall, Tempe, AZ 85281 USA
[21] Inst Jane Goodall Espana, Stn Biol Fouta Djallon, Dindefelo, Region De Kedou, Senegal
[22] Ebo Forest Res Project, BP3055, Yaounde, Cameroon
[23] San Diego Zoo Global, Inst Conservat Res, Escondido, CA 92025 USA
[24] Lincoln Pk Zoo, Lester E Fisher Ctr Study & Conservat Apes, Chicago, IL 60614 USA
[25] Liverpool John Moores Univ, Sch Nat Sci & Psychol, Liverpool L3 3AF, Merseyside, England
[26] Washington Univ St Louis, Dept Anthropol, One Brookings Dr, St Louis, MO 63130 USA
[27] UCL, Dept Anthropol, London WC1H 0BW, England
[28] Frankfurt Zool Soc, Bernhard Grzimek Allee 1, D-60316 Frankfurt, Germany
[29] Univ Ghent, Terr Ecol Unit, KL Ledeganckstr 35, B-9000 Ghent, Belgium
[30] Ctr Suisse Rech Sci, Tai Chimpanzee Project, BP 1301, Abidjan 01, Cote Ivoire
[31] Univ Neuchatel, Inst Biol, CH-2000 Neuchatel, Switzerland
[32] Univ St Andrews, Sch Psychol & Neurosci, St Andrews KY16 9JP, Fife, Scotland