Altruistic behavior is a puzzling phenomenon that occurs in a wide range of animal species (5); from insects to humans, many species seem to express helping behavior even at a cost to their own wellbeing. Altruism goes against the theory of natural selection and the idea that animals only behave in ways to increase their own fitness (5). Many ethologists take the stance that seemingly altruistic behavior is still foundationally egoistic (1) which has been backed up by the concepts of kin and group selection (5). Although in many cases, these theories have been proven, they do not explain why some animals exhibit helping behavior towards other species.
Cetaceans have been recorded helping other species in distress for centuries (3), but Humpback whales (Megaptera novaeangliae), in particular, have received recent attention for their altruistic behavior towards other marine animals during killer whale (Orcinus orca) attacks. A study by Pitman et al. (2016) reviewed 115 interactions between humpbacks and killer whales and found that humpbacks frequently approach killer whales when they are attacking, more so when it involves other species. There are accounts of humpbacks interfering and aiding several other cetacean species, sea lions, seals and even sunfish (6). Although protecting other humpback whales could be explained by kin or group selection, there is no obvious benefit for the humpback to spend time and energy helping another species. This behavior actually seems to be maladaptive since besides humans, killer whales are the only significant predator of humpback whales (7,8), aside so this behavior could put them in harm’s way.
Humpbacks are the only cetaceans that has been recorded to effectively deflect a killer whale attack (6) and it is possible that humpback’s successful defense-behavior includes an evolved reaction to deliberately interfere with attacking killer whales. Instinctively, humpbacks could be responding to killer whale vocalizations regardless of the prey species, but this doesn’t fully explain the complexities of these interactions. Humpbacks have not been recorded to interfere with killer whales attacking smaller fish, it seems that they mainly assist other marine mammals. Many of the interactions show that humpbacks will go to extreme lengths to remove the threat of an attack on other animals (6). For such an intelligent and highly emotional species, it is hard to assume that these actions are simply instinctual. Furthermore, not all humpbacks exhibit this behavior, which creates another limitation for the instinct theory. Many of the whales that do participate in interference were recorded to have scars from a previous killer whale attack (2.). This allows for the possibility that humpbacks are responding from experiential memory and many have a personal history which would drive them to interfere.
Whales are ranked as one of the most intelligent and emotionally cognizant species, alongside great apes and humans (4). Like many whales, humpbacks have a highly developed degree of general intelligence indicating that there is capacity for empathic responses. Using scientific reasoning, Pitman et al. (2016) concluded that “[i]nterspecific altruism, even if unintentional, could not be ruled out” (pp.7). It is still not definitive that humpbacks are acting from true altruist motives, although stands out as one of the strongest cases for selflessness in the animal kingdom. What is clear, is that even with centuries of investigation, science still has much learn about animal’s cognitive abilities.
1. Batson, C.D. and Shaw, L.L., 1991. Evidence for altruism: Toward a pluralism of prosocial motives. Psychological inquiry, 2(2), pp.107-122.
2. Bittel, J. 2016. Why Humpback Whales Protect Other Animals from Killer Whales. National Geographic. Available at: https://news.nationalgeographic.com/2016/08/humpback-whales-save-animals-killer-whales-explained/ [accessed 6 Dec 17]
3. Caldwell, M. C., and D. K. Caldwell. 1966. Epimeletic (care-giving) behavior in Cetacea. Pages 755–788 in K. S. Norris, ed. Whales, dolphins, and porpoises. University of California Press, Berkeley, CA.
4. Marino, L., McShea, D.W. and Uhen, M.D., 2004. Origin and evolution of large brains in toothed whales. The Anatomical Record, 281(2), pp.1247-1255.
5. Okasha, S. 2013 "Biological Altruism", The Stanford Encyclopedia of Philosophy (Fall 2013 Edition), Edward N. Zalta (ed.), Available at: https://plato.stanford.edu/archives/fall2013/entries/altruism-biological/. [accessed 6 Dec 17].
6. Pitman, R.L., Deecke, V.B., Gabriele, C.M., Srinivasan, M., Black, N., Denkinger, J., Durban, J.W., Mathews, E.A., Matkin, D.R., Neilson, J.L. and Schulman‐Janiger, A., 2017. Humpback whales interfering when mammal‐eating killer whales attack other species: Mobbing behavior and interspecific altruism?. Marine Mammal Science, 33(1), pp.7-58.
7. Reeves, R. R., J. Berger and P. J. Clapham. 2006. Killer whales as predators of large baleen whales and sperm whales. Pages 174–187 in J. A. Estes, D. P. DeMaster, D. F. Doak, T. M. Williams and R. L. Brownell, Jr., eds. Whales, whaling, and ocean ecosystems. University of California Press, Berkeley, CA.
8. Saulitis, E., L. A. Holmes, C. Matkin, K. Wynne, D. Ellifrit and C. St-Amand. 2015. Bigg's killer whale (Orcinus orca) predation on subadult humpback whales (Megaptera novaeangliae) in Lower Cook Inlet and Kodiak, Alaska. Aquatic Mammals 41:341–344.