Reproduction and life history
Female
	Minimum age at first observed copulation	5.2 years
	Age at first parturition	10.6 years (N = 6, range = 9.1-12.1)
	Number of producing their first infant in natal group	5 (N = 18)
	Number of producing their first infant in non-natal group	9 (N = 18)
	Number of females emigrating from the natal group after the first birth	4 (N = 5)
	Iinterval between surviving birth	4.6 years (N = 9, range = 3.4-6.6)
	Iinterval between death of infant and the next birth	2.2 years (N = 3, range = 1.4-2.7)
Infant
	Sex ratio at birth (number of male/number of female)	0.94 (N = 64)
	Mortality (primiparous)	33.3% (N = 21)
	(parous)	20% (N = 25)
	Mortality (first year)	19.6% (N = 46)
	(second year)	6.5% (N = 46)
Male
	Age at emigration from natal group	12.7 year (N = 6, range = 9.6-14.1)
	Maximum number of silverback male within a group	2
	Priportion of multi-male group in the population	8%
Source:
[140] Yamagiwa J., Basabose A.K., Kahekwa J., Bikaba D., Ando C., Matsubara M., Iwasaki N. & Sprague D.S. (2012) Long-term research on Grauer's gorillas in Kahuzi-Biega National Park, DRC: life history, foraging strategies, and ecological differentiation from sympatric chimpanzees. In: Kappeler P.M., Watts D.P. (eds.) Long-Term Field Studies of Primates. Springer, Heidelberg. pp 385-412
[143] Yamagiwa J., Kahekwa J. & Basabose A.K. (2003) Intra-specific variation in social organization of gorillas: implications for their social evolution. Primates 44: 259-369