A histological study of the skin, hair follicles and moult of the hooded seal (Cystophora cristata [Erxleben, 1777])

Figures & data

Table 1. Numbers of male and female hooded seals collected in the Denmark Strait between 20 June and 11 July 1972.

	Males			Females
Date	N	Percentage of total	Accumulated percentage	N	Percentage of total	Accumulated percentage
20/6	2	0.41	0.41	3	0.80	0.80
21/6	14	2.84	3.25	22	5.87	6.67
22/6	33	6.69	9.94	39	10.40	17.07
28/6	42	8.52	18.46	38	10.13	27.20
29/6	73	14.81	33.27	73	19.47	46.67
1/7	9	1.83	35.10	12	3.20	49.87
2/7	36	7.30	42.40	32	8.53	58.40
3/7	56	11.36	53.76	35	9.33	67.73
4/7	69	14.00	67.76	35	9.33	77.06
5/7	45	9.13	76.89	21	5.60	82.66
7/7	7	1.42	78.31	6	1.60	84.26
8/7	29	5.88	84.19	24	6.40	90.66
9/7	47	9.53	93.72	19	5.07	95.73
10/7	9	1.83	95.55	3	0.80	96.53
11/7	22	4.46	100.01	13	3.47	100.00
Total	493			375

Table 2. Daily mean ages and age ranges of moulting male and female hooded seals collected in the Denmark Strait, June – July 1972.

	Males				Females
Date	N	Mean age (years)	Age range (years)		N	Mean age (years)	Age range (years)
20/6^a	2	1.5 ± 0.5	1–2		3	2.0 ± 0.5	1–3
21/6^b	14	7.0 ± 1.1	1–17		22	4.9 ± 2.6	1–11
22/6^b	32	5.2 ± 1.5	1–15		39	4.7 ± 3.8	1–20
28/6^b	42	5.2 ± 3.7	1–14		38	4.2 ± 3.4	1–17
29/6^b	73	4.8 ± 3.7	1–17		71	6.1 ± 5.9	1–31
1/7^a	9	8.3 ± 5.2	1–17		12	7.0 ± 7.5	2–30
2/7^b	36	7.1 ± 4.4	1–16		32	4.6 ± 3.8	1–14
3/7^b	54	7.7 ± 4.3	1–19		34	5.9 ± 0.8	1–22
4/7^b	67	7.0 ± 3.7	1–16		35	5.5 ± 3.9	1–13
5/7^b	45	8.2 ± 4.5	1–18		21	6.7 ± 5.3	1–20
7/7^a	7	5.6 ± 5.8	2–19		6	3.8 ± 2.6	1–8
8/7^a	28	6.7 ± 3.8	1–16		24	5.1 ± 1.5	1–14
9/7^b	46	8.0 ± 5.2	1–22		19	4.8 ± 3.5	1–16
10/7^a	9	5.6 ± 2.9	3–11		3	9.7 ± 6.3	1–15
11/7^b	22	6.2 ± 3.0	1–12		13	3.9 ± 2.3	1–9

^a Samples too small. ^b Some ages missing.

Table 3. Daily pelage follicle activity stages in male and female hooded seals collected in the Denmark Strait, June – July 1972.

	Males (N = 45)		Females (N = 23)
Date	Activity stages	N	Activity stages	N
21/6	4–6	8	–	–
22/6	5	1	4–5, 7–8, 10 + ^a	6
28/6	5–8	4	6–8	2
29/6	5–7	3	5–6, 8	5
1/7	6–8	2	–	–
2/7	5–10 +^a	6	5–6	2
3/7	5–8	5	8–10+	2
4/7	5–7	5	6, 9–10 ^a	2
5/7	5–7	3	6–7	2
7/7	7	1	5–6	2
8/7	7	2	4–5	2
9/7	10	1	–	–
10/7	6	1	–	–
11/7	5–6	1	–	–

^a Not all intermediate stages.

Table 4. Hair follicle activity stages at six to 11 body sites on four adult hooded seals collected in the Denmark Strait, June – July 1972.

	Field number
	Sex/age (years)
	72/7	72/161	72/532	72/697
Body site	Male/2	Female/17	Male/1	Female/1
1 Neck	–	8	7–8	6–7
2 Back	4	5–7(?)	6–7, 7–8 ^c	5
3 Rump	4–5, 6	5–7(?)	7	–
4 Throat	–	8	8	7
5 Chest	4–5	7–8	8	5
6 Belly	5	8–9	7	5–6
7 Axilla	–	8	5–6	5
8 Fore flipper (d ^a)	4	6–7	6–7	4–5
9 Fore flipper (v ^b)	5	6	7	6
10 Hind flipper (d)	–	6–7	7–8	5–6
11 Hind flipper (v)	–	8–9	8	5–6

^a Dorsal. ^b Ventral. ^c Two samples.