SUPPLEMENTARY TABLES

Table S1. Expansion of the GHC behaviour in the Chimfunshi Wildlife Orphanage Trust chimpanzee groups that engaged in the GHC behaviour throughout 2007-2011. Information on alljuvenile chimpanzees that reached at least the age of 5in 2011 is displayed (YOB = year of birth; Empty cell= no GHC behaviour observed; GHC partner in writing = kin; GHC partnerin number = non-kin).

Sex / YOB / 2007 / 2010 / 2011
Group 1
Bob / ♂ / 2001 / Mother + 2 / Mother + 1
Gerard / ♂ / 2002 / Mother / Mother / Mother + 1
Ilse / ♀ / 2002 / Mother / Mother / Mother
Brandon / ♂ / 2006
Regina / ♀ / 2006 / Mother / Mother
Rusty / ♂ / 2006 / Mother
Group 2
David / ♂ / 2001 / Mother + 1 / Mother + 1 / 2
Debbie / ♀ / 2001 / Mother / Mother + 5 / Mother + 2
LJ / ♂ / 2001 / Sister + 1 / Mother + sister + 4
Marc* / ♂ / 2001 / Mother
Maxine / ♀ / 2001 / Mother + 1 / Mother + 1 / Mother + 2
Thomas~* / ♂ / 2001 / 3
Tilly^ / ♀ / 2001 / Mother / Mother + 3 / Mother + sister + 3
Claire / ♀ / 2002 / Mother / Mother + sister + 1
Vis / ♂ / 2002 / - / 1
Doug / ♂ / 2003 / Mother / Mother + sister / Mother + sister + 1
Nina / ♀ / 2003 / Mother / Mother + sister + 1 / Mother + sister + 2
Toni# / ♀ / 2003 / Sister / Sister
Daisey / ♀ / 2004 / Mother / Mother + 3
Taylor^ / ♀ / 2004 / Mother + sister
Mary / ♀ / 2005 / 1
Long John / ♂ / 2006
Max / ♂ / 2006

~ mother died in 2007, prior to data collection

* passed away prior to data collection 2010

^ sibling pair

& sibling pair

# mother died in 2008