Image: Sperm-Whale-Scale-Chart-SVG-Steveoc86

Description: The size of sperm whales (Physeter macrocephalus) at various stages of growth and maturity, showing a newborn, a physically mature male and female, and the largest males, with a human diver for scale.

• Newborn sperm whales are between 3.7 (shown here) and 4.3m in length.[1]

• Sperm whales exhibit a large amount of size based sexual dimorphism, with males generally being much larger than females. Female sperm whales are physically mature at about 10.6 - 11m in length and generally don't grow much larger than 12m. Male sperm whales are physically mature at about 16m in length and generally reaching a maximum of about 18-19m.[2][3][4][5][6][7] Animals often exhibit individual variation (intraspecific variation), and exceptional individuals of both sexes have been recorded to reach larger than average sizes.[4]

• There is disagreement as to the largest recorded male sperm whale. There have been historical accounts of adult males approaching or exceeding ~80ft (~24m). Some authors are sceptical of these claims, generally being considered exaggerations or measured along the curves of the body as opposed to between pegs.[5][6] Some authors consider a male measured in 1950 at 20.7m in length to be the largest officially recorded.[6][8] However, larger males have been recorded in the International Whaling Commissions whaling records, including a male that was reported at 24m in length in 1933, which was supported by McClain et al. (2015) as the largest recorded. There is also a jaw in the London Natural History Museum that suggests a larger individual.[4][8] Regardless of the exact size of the largest males, exceptionally large sperm whales are very rare with 95% of those measured being below 15m. There is also evidence that sperm whales have reduced in average size over time, which might be due to heavy whaling.[4][5] However, this probably doesn't explain the difference in size between the more extreme historical accounts & records and more recent records.[5]

• Note: Whales are usually measured from snout to the notch between tail flukes,[4] the tail flukes add some additional length in the silhouettes.

References

↑ Ruelas-Inzunza, J (2002-09-01). "Distribution of Cd, Cu, Fe, Mn, Pb and Zn in selected tissues of juvenile whales stranded in the SE Gulf of California (Mexico)". Environment International 28 (4): 325–329. DOI:10.1016/S0160-4120(02)00041-7. ISSN 0160-4120.

↑ Whitehead, Hal (2018-01-01), “Sperm Whale: Physeter macrocephalus”, in Encyclopedia of Marine Mammals (Third Edition)[1], Academic Press, DOI:10.1016/b978-0-12-804327-1.00242-9, ISBN 978-0-12-804327-1, pages 919–925

↑ Shirihai, H. and Jarrett, B. (2006) Whales, Dolphins, and Other Marine Mammals of the World, Princeton: Princeton Univ. Press, pp. 21–24 ISBN: 0-691-12757-3.

↑ a b c d e McClain, Craig R. (2015-01-13). "Sizing ocean giants: patterns of intraspecific size variation in marine megafauna". PeerJ 3: e715. DOI:10.7717/peerj.715. ISSN 2167-8359.

↑ a b c d Ellis, Richard (2011) The Great Sperm Whale: A Natural History of the Ocean's Most Magnificent and Mysterious Creature, Zoology, 179, United States of America: University Press of Kansas, p. 432 ISBN: 978-0-7006-1772-2.

↑ a b c Wood, Gerald (1983) The Guinness Book of Animal Facts and Feats ISBN: 978-0-85112-235-9.

↑ Perry, Simona L. (1999) The Great Whales: History and Status of Six Species Listed as Endangered Under the U.S. Endangered Species Act of 1973, NMFS Publications Office, pp. 1−74

↑ a b Carwardine, Mark (2008) Animal Records, Category:New York: Sterling ISBN: 9781402756238.
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