The Collapsed Dorsal Fin of Captive Orcas
For many years, there has been scientific debate concerning the reason why the naturally straight and very tall dorsal fin of killer whales (orcas) sometimes flops over. While there are various theories explaining this phenomenon, it remains a fact that “dorsal fin collapse” or “flaccid fin syndrome” is much more common in captive whales (1).
Life in the wild is very different than life in captivity. Each day in the wild, orcas may swim hundreds of miles, often in a straight line and at deeper depths (2). The enormous pressure of the water against the heavy fin helps to hold and support it. But in captivity, the orca not only spends much of its time at the water surface, it also doesn’t swim very far, and when it does, it’s typically in repetitive, circular patterns.
Drooping dorsal fins are rare in wild male orcas* yet happens with almost all male orcas in captivity. Remember “Keiko” of Free Willy fame?
Sad as this may be, what does it have to do with us?
Are We Evolving in a Way That’s Similar to Animals in Captivity?
Many generations ago, we used to move more, much more, because we had to. There were everyday chores to be done and few conveniences to rely on. We walked long distances to retrieve water. We grew, harvested, and made our own food. Our bodies have evolved to perform hundreds of movements, but many have been lost to disuse. Common examples are the difficulty many people have getting up and down from the floor or difficulty squatting properly (or easily) to retrieve fallen objects. As a result, we have become weaker than our hunter-gatherer ancestors, and “captive” in our modern lifestyles (3).
Nevertheless, I for one do not intend to give up my car, my washer/dryer, or aim to explore homesteading.
What To Do?
The solution is actually simple and should be implemented gradually in order to allow for safe adaptation. It lies in finding ways to include more movement each day. Yes, it’s important that we participate in Strong Bones class, or a yoga class, or have a gym membership, but I’m sorry to say, that’s not enough.
Aim to purposefully increase how much you physically interact with your environment each day. Walking more would be a wonderful start. Consider, for example, parking your car farther away from the entrance to the store. Islam et al. (4), discusses the novel concept of “exercise snacks” – very small bouts of exercise performed periodically throughout the day.
The freedom of being able to move when we want, how we want, whenever we want, comes with a greater sense of wellbeing which can’t be overstated…and it may prevent our own human version of collapsed dorsal fin syndrome.
* Researchers believe that dorsal fin collapse in wild whales may be due to age, stress, or injury.
References
1. Aves F, et al. The Incidence of Bent Dorsal Fins in Free-Ranging Cetaceans. Journal of Anatomy, 2018, 232(2):263-269.
2. Marine Mammals in Captivity. The Humane Society of the United States.
3. Ryan T and Shaw, C.N. Gracility of the Modern Homo Sapiens Skeleton is the Result of Decreased Biomechanical Loading. Proc. Nat. Acad. Sci. U.S.A. 2015, 112(2):372-
4. Islam H, et al. Exercise Snacks: A Novel Strategy to Improve Cardiometabolic Health. Exerc Sport Sci Rev. 2022 Jan 1;50(1):31-37.