The BBC strand of a wildlife documentary series, entitled Natural World, have a new episode up on the BBC Iplayer focusing on recent scientific research on the globally distributed killer whale (Orcinus orca). It is available to view here, although readers outside of the UK may have trouble watching it online (If you have any links please leave a comment!).
It was whilst watching the program, and its discussion on whether there are different species of killer whale (likely 3-5, with various sub-species), that it reminded of the Dmanisi Homo erectus fossils (Lordkipanidze et al. 2013) which were subject of the previous post. Lordkipanidze et al. (2013: 330) postulated that the morphology of the 5 Homo erectus crania present at Dmanisi, Georgia, represent, when examined against comparable material, the evidence for wide morphological differences within and among early Homo, possibly indicating rather less individual species than is currently documented and described.
The Natural World episode highlighted the differences between killer whale ‘cultural’ groups and species with niché but distinct differences in external anatomy (body size, eye and saddle markings, shape and size of dorsal fins), vocalisation and the different hunting methods used when groups targeted varying prey groups. This is important as it will help to inform on how humans try to conserve killer whale populations around the globe as an understanding of the distinct species could have an important ecological impact on what groups of killer whales are under threat the most. Of course the big difference between the above comparison was the use of DNA testing and active observational fieldwork, if only we could test the early Homo fossils in such a way!
Further into the program we came across evidence of an individual killer whale who had likely been maimed as a juvenile and who had been adopted, at different times, by no less than 4 different pods of killer whales. There was also footage of said killer whale shadowing and receiving food from one member of her current pod who could successfully hunt (whether this was deliberate is another question). This reminded me of a nice little paper by Fashing & Nguyen (2011) of the relevance of behaviour towards disabled, injured or dying individuals among animal groups and it’s relevance towards palaeopathology.
Palaeoanthropologists should take into account the wider aspect of how animals treat members of their own species when they are disabled, injured or dying, as Fashing & Nguyen (2011: 129) note that ‘recent evidence from paleoanthropology indicates that inferences into the evolution of human behavior based solely on a chimpanzee model are less informative than previously believed’. Lordkipanidze et al. (2013), in their study, compare the Dmanisi individuals against modern Homo sapiens and chimpanzees, amongst others, but it could be said that these two groups in particular do not reflect good study comparative groups as their anatomical plasticity is generally quite homogeneous. As ever, of course, further research is needed and I for one look forward to it.
The program also debated the troubling nature of the capture of killer whales for the purposes of entertainment for large sea life centers across the world, a practice that has now been largely banned in the Western World. There is a haunting passage in the Natural World episode showing archive footage of the frenzy of killer whale captures during the 60’s and 70’s, with an appropriately sinister (and awesome) Pink Floyd track playing in the background. Killer whales are, by their nature, large social predators – they need the security of their family pods and the sea environment in which to live and to hunt.
At SeaWorld, in the United States of America, there have been a recorded 100 separate episodes of aggression towards humans from captive killer whales since 1988, and there have been 4 recorded fatalities of trainers involving captive killer whales across the globe. Let me re-iterate here that killer whales pose little threat to humans in the wild, that there has been no recorded human death by killer whale in the wild but there have been incidents (see list). Clearly captivity leads to abnormal behaviour amongst these amazing creatures, as it can be said for many animal species (worth a watch is the 2013 documentary Blackfish).
All in all, this was an enlightening program on the advances made in studying the killer whale, highlighting the distinct hunting differences, group structure and vocalisation of an apex predator who has both inspired and caused fear in humanity throughout the ages. It is well worth watching the episode, if not the series, for insights into the natural world. Previous episodes worth a watch also deal with the remarkable walrus and the delightful orangutan.
Watch the BBC documentary here (United Kingdom residents only).
Fashing, P. J. & Nguyen. 2011. Behavior Towards the Dying, Diseased, or Disabled Among Animals and its Relevance to Paleopathology. International Journal of Paleopathology. 1 (2-3): 128-129.
Lordkipanidze, D., Ponce de León, M. S., Margvelashvili, A., Rak, Y., Rightmire, G. P., Vekua, A. and Zollikofer, C. P. E. 2013. A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo. Science. 342 (6156): 326-331. (Full article here, email if this doesn’t work).