Table 1.

Age- and rank-related changes in the acoustic parameters of groans.

	Age					Rank
Acoustic variable	Relationship	df	F	P	R2	Relationship	df	F	P	R2
F0max	linear	1,16	6.85	0.02	0.13	log	1,12	6.15	0.03	0.15
F0mean	linear	1,16	10.90	0.005	0.23	log	1,12	3.15	0.10	0.23
F0min	linear	1,16	42.78	< 0.0001	0.30	log	1,12	0.69	0.42	0.27
Jitter	linear	1,16	0.01	0.94	0.06	log	1,12	2.44	0.14	0.07
Duration	linear	1,16	0.54	0.47	0.21	log	1,12	0.04	0.85	0.23
Pulses	linear	1,16	2.30	0.15	0.18	log	1,12	0.82	0.38	0.18
Frmax	linear	1,16	2.34	0.15	0.12	log	1,12	2.02	0.18	0.17
F1min	linear	1,16	0.07	0.79	0.16	quadratic	1.11	1.14	0.31	0.13
F2min	linear	1,16	2.35	0.15	0.15	quadratic	1.11	0.21	0.65	0.16
F3min	linear	1,16	1.54	0.23	0.09	quadratic	1.11	1.27	0.28	0.06
F4min	quadratic	1,15	5.82	0.03	0.26	quadratic	1.11	3.27	0.10	0.25
F5min	quadratic	1,15	1.85	0.19	0.23	quadratic	1.11	4.10	0.07	0.23
F6min	quadratic	1,15	15.40	0.001	0.38	linear	1,12	4.55	0.05	0.26
Dfmin	quadratic	1,15	8.09	0.01	0.37	linear	1,12	3.16	0.10	0.30

Bold types indicate significant and marginally significant results.

Results of generalized linear mixed models to investigate variation in the measured acoustic variables, in relation to male age and dominance rank. Both age and dominance rank influence the F0 contour and the minimum frequencies of highest formants.