We had a fantastic week last week with some special visitors making their way past Plettenberg Bay, and only one boat full of passengers were lucky enough to see them! I am talking about a pod of 7 orcas, or killer whales, which were sighted roughly 4 nautical miles from the coast – what an incredible experience that must have been! Orcas Orcinus orca occur in South Africa, but are rarely sighted here in Plettenberg Bay. They are a cosmopolitan species occurring in practically any marine region, to the point of being suspected to be the second-most widely ranging mammal on Earth, after humans. Orcas are beautifully marked, being primarily black above and white below with a white saddle behind the very large dorsal fin and white oval patches behind the eye. This black and white marking is similar to that of pandas, giving them the nickname sea pandas. Sea pandas, orcas, killer whales, there are a number of names for this species. Killer whale is the most emotive of these, and is not altogether a correct term. The name originates from the mistranslation of the 18th century Spanish name “asesina de ballenas” which directly translates to killer of whales, which is what could have been observed – pods of orcas hunting whales. However, while orcas are classified as toothed whales, they are in fact more closely related to dolphins than they are to whales. Orcas are apex predators hunted only by humans, and will hunt in packs feeding on fish, squid, birds, seals, dolphins, and even large baleen whales. Currently, all orcas worldwide belong to the same species but it has been suggested that separate species status needs to be awarded to certain groups based on morphology and diet specialization. For now, orcas are listed as Data Deficient according to the IUCN and more research is needed on the species morphology, abundance, distribution, and threats, yet only once the taxonomy of the genus Orcinus has been finalized can the IUCN status be awarded.
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. 366. Random House Struik Publishers, Cape Town.
- Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. and Pitman, R.L. 2013. Orcinus orca. The IUCN Red List of Threatened Species 2013. Accessed: 2016-09-10. URL: http://www.iucnredlist.org/details/full/15421/0