
Testes Size, Vaginal Complexity and Behavior in Toothed Whales: Arms Race or Tradeoff Model?
- Behavior
Abstract
Sexual selection influences both genital diversity and mating behaviors, yet the integrated coevolution of pre- (behavioral) and postcopulatory (anatomical) traits in both sexes has received little attention. Traits could potentially evolve through an arms race model of escalations in male persistence and female resistance, and/or through a tradeoff model of inverse correlations between investments in pre- and postcopulatory traits. Pre- and postcopulatory traits of dusky dolphins (Lagenorhynchus obscurus) were compared with bottlenose dolphins (Tursiops spp.) and harbor porpoises (Phocoena phocoena). Relative testes size and vaginal complexity were measured from dissected specimens. Behavioral traits were analyzed from video recordings of individuals in free-ranging populations. Female precopulatory and male postcopulatory traits were associated, whereas female and male postcopulatory traits or female pre- and postcopulatory traits were not associated. Dusky dolphins differed substantially in several behavioral traits including longer durations of mating group interactions, lower rates of copulation attempts, more males per group, and higher female behavioral resistance. To explore complex processes of integrative coevolution, we recommend future research incorporate pre- and postcopulatory traits and focus on alternative measures of female resistance and male persistence.
Orbach, D.N., Packard, J.M., Keener, W., Ziltener, A. and Würsig, B., 2019. Testes size, vaginal complexity, and behavior in toothed whales (odontocetes): Arms race or tradeoff model for dusky dolphins (Lagenorhynchus obscurus), harbor porpoises (Phocoena phocoena), and bottlenose dolphins (Tursiops spp.)?. Journal of Comparative Psychology, 133(3), p.359.
Bill Keener
Related Publications
{"image":"\/Animals\/Patients\/Harbor seals\/hs-by-bill-hunnewell-c-the-marine-mammal-center.jpg","alt":"harbor seal in a life preserver enrichment item","title":"Enrichment as a Tool for Rehabilitating Harbor Seals","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/enrichment-as-a-tool-for-rehabilitating-harbor-seals","label":"Research Paper"}

{"image":"\/Animals\/Wild\/Harbor porpoise\/cropped-images\/harbor-porpoises-foraging-by-marc-webber-c-the-marine-mammal-center-4-0-1276-996-1618438446.jpg","alt":"harbor porpoises eating a large fish","title":"Prey-Related Suffocation in Harbor Porpoises","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/prey-related-suffocation-in-harbor-porpoises","label":"Research Paper"}

{"image":"\/Animals\/Wild\/Harbor porpoise\/cropped-images\/harbor-porpoises-aerial-view-badge-by-marc-webber-c-the-marine-mammal-center-0-88-1280-999-1618509985.jpg","alt":"Harbor porpoises seen from above","title":"Coevolution of Asymmetric and Spiraled Genitalia with Unique Mating Behavior","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/coevolution-of-asymmetric-and-spiraled-genitalia-with-unique-mating-behavior","label":"Research Paper"}

Coevolution of Asymmetric and Spiraled Genitalia with Unique Mating Behavior
Read More{"image":"\/Animals\/Wild\/Harbor porpoise\/harbor-porpoise-shutterstock-2.jpg","alt":"harbor porpoise","title":"Harbor Porpoises Catching and Handling Large Fish","link_url":"https:\/\/www.marinemammalcenter.org\/publications\/harbor-porpoises-catching-and-handling-large-fish","label":"Research Paper"}

Related News
{"image":"\/Animals\/Wild\/Harbor seal\/cropped-images\/harbor-seals-shutterstock-107-0-1270-992-1744225508.jpg","alt":"A group of harbor seal pups and mothers on the beach during pupping season.","title":"Your Guide to Seeing Harbor Seal Pups in California","link_url":"https:\/\/www.marinemammalcenter.org\/news\/your-guide-to-seeing-harbor-seal-pups-in-california","label":"News Update","date":"2025-04-10 00:00:00"}

{"image":"\/Animals\/Wild\/Humpback whale\/cropped-images\/humpback-whale-sea-lions-photo-c-bill-hunnewell-102-0-1270-992-1743014972.jpg","alt":"A California sea lion jumps out of the ocean next to a humpback whale showing its tail and another whale showing its back.","title":"What is the Loudest Animal on Earth? And Other Animal Trivia","link_url":"https:\/\/www.marinemammalcenter.org\/news\/what-is-the-loudest-animal-on-earth-and-other-animal-trivia","label":"News Update","date":"2025-03-26 07:00:00"}

{"image":"\/Animals\/Wild\/Guadalupe fur seal\/cropped-images\/gfs-wild-photo-by-marc-webber-193-0-1270-992-1739906952.jpg","alt":"A Guadalupe fur seal floats in the water with its flippers raised. ","title":"Your Visual Guide to Sea Lion and Seal Behavior","link_url":"https:\/\/www.marinemammalcenter.org\/news\/your-visual-guide-to-sea-lion-and-seal-behavior","label":"News Update","date":"2025-02-18 02:00:00"}

{"image":"\/Animals\/Wild\/Gray whale\/gray-whale-baleen-shutterstock.jpg","alt":"A gray whale\u2019s head rises above the ocean surface with its mouth open showing baleen.","title":"What Do Whales Eat? And Other Foodie Trivia","link_url":"https:\/\/www.marinemammalcenter.org\/news\/what-do-whales-eat-and-other-foodie-trivia","label":"News Update","date":"2024-11-22 11:51:35"}
