Development of foraging skills in two orangutan populations: needing to learn or needing to grow?

Table 3 GLMMs of feeding rate, expressed as percentage of the mothers’ feeding rates, as a dependent variable, with (a) and without (b) including the number of processing steps as an independent variable

Effect	Effect type	Estimate	Std-Error	P-value	N (128)	AIC
a)
Age	Fixed	7.96	0.94	<0.001	cont.	964
sigmoid(Age)	Fixed	−36.34	56.24	0.52	-
Processing steps	Fixed	−4.77	1	<0.001	5
Sex (male = 0)	Fixed	−19.58	10.5	0.062	2
Site (Tuanan = 0)	Fixed	−120.91	70.31	0.085	2
Age x Sex	Fixed	4.94	1.27	<0.001	-
sigmoid(Age) x Site	Fixed	126.58	71.67	0.078	-
Individual	Random	-	-	-	21
Food Item	Random	-	-	-	34
b)
Age	Fixed	7.88	0.9	<0.001	cont.	981
sigmoid(Age)	Fixed	−69.13	55.47	0.212	-
Sex (male)	Fixed	−21.27	10.09	0.035	2
Site (Tuanan = 0)	Fixed	−130.81	69.44	0.06	2
Age x Sex	Fixed	5.56	1.24	<0.001	-
sigmoid(Age) x Site	Fixed	139.4	70.88	0.049	-
Individual	Random				21
Food Item	Random				34

Shown are effects, estimates, standard errors and p-values as well as number of levels for the categorical variables and AIC values of the models. The number in parentheses represents the total number of individual - age - species combinations
Bold font indicates significance at the 0.05 level

ISSN: 1742-9994