How long do they live? Researchers know that Sperm whales can reach at least 77 years old .
Where are they found? Sperm whales seem to prefer tropical oceans, but they can be found throughout the world’s waters . See figure 1.
What do they eat? Although Sperm whales will eat many different species, their absolute favorite meal in the whole world is giant squid .
What do they look like? They’re rather large creatures that can reach 67 feet in length and weigh 63 tons . See figures 2 and 3.
Thanks to a really interesting Biology II course as an undergraduate I found out that the Sperm whale species has the largest brain in the world. It can weigh up to 17 pounds! See Figure 5.
How do they reproduce? Sperm whales reach sexual maturity between 8 to 10 years of age. Interestingly, males are not allowed to mate until they are in their mid 20’s due to social status ranking among males . I could not find any information regarding reproductive senescence of this species.
How do scientists know how old they are? Estimation data based on growth layer groups of the teeth . Some mark and tag studies have been done, but not on a large scale.
So what are we lacking? OOH, let me start with what we have. The nuclear genome for Physeter macrocephalus is uploaded to the NCBI website. We do not have comprehensive information about reproductive senescence in this species, but it’s not exactly an easy thing to study. Age validation by means of non-invasive techniques would be handy too.
Conservation status: Sperm whales are listed as vulnerable by the IUCN.
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- Carey, J., and D. Judge. “Longevity records: Life spans of mammals, birds, amphibians, reptiles, and fish.” On-line). Accessed September 14 (2002): 2005.
- Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. (2008). “Physeter macrocephalus“. IUCN Red List of Threatened Species.Version 2008. International Union for Conservation of Nature.
- Evans, Karen, and Mark A. Hindell. “The diet of sperm whales (Physeter macrocephalus) in southern Australian waters.” ICES Journal of Marine Science: Journal du Conseil 61.8 (2004): 1313-1329.
- “Physeter macrocephalus, Sperm Whale”. marinebio.org.
- Evans, K. A. R. E. N., et al. “Factors affecting the precision of age determination of sperm whales (Physeter macrocephalus).” Journal of Cetacean Research and Management 4.2 (2002): 193-202.