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Sperm Whales and the Bends

Bone remodeling in whales

Bone remodeling in whales. Image taken from Moore & Early article.

Whilst looking into the skull of a sperm whale I came across this article looking at sperm whales and the bends and how some of the bones are effected. I have never really considered before that marine animals could suffer from this condition as one would assume that they would adapt for live in the deep ocean. The article investigating this is entitled ‘Cumulative Sperm Whale Bone Damage and the Bends’ by Moore and Early. See below for the full citation for the article. The feature image of this page was taken from this article and shows progressive erosion and remodeling of dysbaric osteonecrosis in he sub-articular rib bone surface, from a calf to a mature adult sperm whale.

Osteonecrosis is pathology of deep diving in humans and also been suggested as a  progressive condition in sperm whales. An examination of a male showed pitted and eroded bones in places including rib and chevron bone articulation and nasal bones. These also showed joint surface erosion in CT images and x-rays. In the histological examination no bacteria cultures were found and there was no evidence of infection. By observing 16 sperm whale skeletons, complete or partial, of varying size and age range found an increase in bone erosion and remodeling as bony length increased.

The article suggests that as sperm whales under go dysabaric stress this is the likely cause of osteoncrosis in whales and are therefore not immune to the effects caused by deep diving. In their supplementary material the authors suggest that as there is evidence of bone erosion than other effects may also be present. An example of this is decompression sickness. If marine mammals are not adapted anatomically to avoid this sickness then their diving behavior, and therefore their foraging behavior, could be shaped by this. The authors suggest a further look at their diving behavior and whether exposure to loud sounds or sonar effects this.

There have been many studies investigating the effects of sonar on marine mammals and the possibly of causing mass standings. The majority of these studies have been focused on the beaked whale, although research is still ongoing in this area. The possible effects of noise caused by humans, such as naval sonar, needs to be further investigated in order to see if a link between standings and sonar exists to try to combat the issue.

Full citation:

Moore, M. J. and G. A. Early (2004). “Cumulative Sperm Whale Bone Damage and the Bends.” Science 306(5705): 2215.

Related Articles

Cox, T. M. et al. (2006). ‘Understanding the impacts of anthropogenic sound on beaked whales’. J. CETACEAN RES. MANAGE. 7(3):177–187, 2006

Tyack, T. L. et al. (2006). ‘Extreme diving in beaked whales’. J Exp Biol 209, 4238-4253. doi: 10.1242/​jeb.02505

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