Table 5.

Time–event model of maternal sister age difference on middle-aged female reproduction (ages 22–43) in Asian elephants. Terms retained and rejected in the final model (determined using AIC) are shown above and below the intercept, respectively. Mother's identity was fitted as a random term.

term	estimate	s.e.	Z-value	p-value
female age	−0.2	0.02	−1.4	0.16
age difference: 11–15 years older	−6.19	3.5	−1.7	0.07
female age × age difference: 11–15 years older	0.3	0.18	1.9	0.06
intercept of full model	−2.04	0.54	−3.8	<0.01
mother's origin (0 = wild-born)	0.28	0.21	1.32	0.18
mother's living status (0 = dead)	−0.19	0.23	−0.8	0.4
birth order (0 = not first-born)	−0.01	0.25	−0.05	0.96
age difference: 0–5 years younger	−0.63	1.27	−0.49	0.62
age difference: 6–10 years younger	−1.5	1.17	−1.3	0.18
age difference: 11–15 years younger	−0.8	1.4	−0.5	0.56
age difference: 0–5 years older	1.79	1.3	1.3	0.18
age difference: 6–10 years older	1.3	1.9	0.67	0.5
female age × age difference: 0–5 years younger	0.02	0.04	0.46	0.64
female age × age difference: 6–10 years younger	0.05	0.04	1.29	0.19
female age × age difference: 11–15 years younger	0.02	0.05	0.5	0.62
female age × age difference: 0–5 years older	−0.05	0.05	−1.03	0.3
female age × age difference: 6–10 years older	−0.04	0.07	−0.6	0.55