Table 1. Information on the sperm whales used in the study.

ID	Sex	Body length (m)	Region	Source	Year of sampling	Estimated age (years)	Number of samples analysed
A	Male	12.2	NW Spain	Captured	1980	16	9
B	Male	11.6	NW Spain	Captured	1980	18	10
C	Female	10.9	NW Spain	Captured	1978	18	9
D	Female	9.5	NW Spain	Captured	1978	20	9
E	Female	10.1	NW Spain	Captured	1978	13	6
F	Male	12.6	Denmark	Stranded	1996	24	7
G	Male	13.2	Denmark	Stranded	1996	27	8
H	Male	12.9	Denmark	Stranded	1996	22	7
I	Male	14.0	Denmark	Stranded	1997	55	12