Swift, spirited seals
It is surely now widespread knowledge that at the base of Robberg Peninsula on the protected bay side there is a very large breeding colony of cape fur seals Arctocephalus pusillus pusillus. They are a charming species, whose antics in the water and on land can keep me entertained for hours, despite being noisy and smelly! Cape fur seals are not considered true seals as they have external ear flaps, and their hind limbs can rotate forward to enable them to walk on land, unlike true seals, such as the elephant seal Mirounga leonine, which lack external ears and are unable to rotate their hind limbs forward and so movement on land is an awkward caterpillar wriggle. Adult male cape fur seals can get up to 300 kg and 2.5 m in size, while females are much smaller at 75 kg and 1.5 m in size. This size difference exists as the males ‘haul out’ during October and violently establish breeding territories, not taking time out to feed for 4-8 weeks. Harems are established in November of 10-40 females which are aggressively defended. Pups are born late November to early December and weigh roughly 6 kg. Interestingly, 6-7 days after giving birth female seals come into oestrous and are mated by the dominant male of their harem. What is even more interesting about this species is that the embryo does not implant in the uterus until 4 months later and then develops for 8 months so that females give birth a year later after being mated. Seal pups are absolutely gorgeous, and make a loud sheep-like ‘baa’ contact call. During summer a number of seal pups end up stranded on our beaches as high seas wash them from their precarious rocky perches, and many of these are successfully rehabilitated and returned to the colony.
Written by: Minke Witteveen
For further reading:
- Branch, G.M., Griffiths, C.L., Branch, M.L. and Beckley, L.E. 2010. Two Oceans: A guide to the marine life of southern Africa. Pp. 362. Random House Struik Publishers, Cape Town.
- Hofmeyr, G.J.G. 2015. Arctocephalus pusillus pusillus. The IUCN Red List of Threatened Species 2015. Accessed: 2016-08-13. URL: www.iucnredlist.org/details/2066/0.