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Female hyenas don't have penises, but it sure looks like they do - and we still aren't quite sure why. To start using Tab for a Cause, go to: http://tabforacause.org/r/minuteearth2 Thanks also to our supporters on https://www.patreon.com/MinuteEarth ___________________________________________ To learn more, start your googling with these keywords: Pseudopenis: a structure that resembles a penis but is developmentally (and functionally) different Masculinization: the process by which female genitalia is made to appear more like male genitalia ___________________________________________ If you liked this week’s video, you might also like: Why It Sucks to Be a Male Hyena https://www.youtube.com/watch?v=PBCNWmU5apE Hyena having a baby at the Buffalo Zoo https://www.youtube.com/watch?v=7rd7TvoPtWM _________________________________________ Subscribe to MinuteEarth on YouTube: http://goo.gl/EpIDGd Support us on Patreon: https://goo.gl/ZVgLQZ And visit our website: https://www.minuteearth.com/ Say hello on Facebook: http://goo.gl/FpAvo6 And Twitter: http://goo.gl/Y1aWVC And download our videos on itunes: https://goo.gl/sfwS6n ___________________________________________ Credits (and Twitter handles): Script Writer: Kate Yoshida (@KateYoshida) Script Editor: Alex Reich (@alexhreich) Video Illustrator: Ever Salazar (@eversalazar) Video Director: Kate Yoshida (@KateYoshida) Video Narrator: Kate Yoshida (@KateYoshida) With Contributions From: Henry Reich, Emily Elert, Peter Reich, David Goldenberg Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder Video Credits: Spotted Hyenas Mating - Olivia Spagnuolo Image Credits: Female Spotted Hyena - Kate Yoshida Spotted Hyena Pseudopenis - Kay Holekamp Striped Hyena (Hyaena hyaena) - Flickr user Jean https://www.flickr.com/photos/7326810@N08/3091611374 Brown Hyena (Parahyaena brunnea) - Bernard DUPONT https://www.flickr.com/photos/berniedup/6472940707/ Proteles cristatus - Dominik Käuferle https://commons.wikimedia.org/wiki/File:Proteles_cristatus1.jpg Squirrel monkey - Wikimedia user Megapixie https://commons.wikimedia.org/wiki/File:Squirrel_monkey-_fuji.jpg Ring tailed lemur - Wikimedia user Sannse https://commons.wikimedia.org/wiki/File:Ring_tailed_lemur_and_twins.jpg Fossa - Ran Kirlian https://commons.wikimedia.org/wiki/File:Cryptoprocta_Ferox.JPG Binturong - Tassilo Rau https://commons.wikimedia.org/wiki/File:Binturong_in_Overloon.jpg ___________________________________________ References: Cunha GR, Risbridger G, Wang H, Place NJ, Grumbach M, Cunha TJ, Weldele M, Conley AJ, Barcellos D, Agarwal S, Bhargava A, Drea C, Hammond GL, Siiteri P, Coscia EM, McPhaul MJ, Baskin LS, Glickman SE. (2014) Development of the external genitalia: perspectives from the spotted hyena (Crocuta crocuta). Differentiation. 87(1-2):4-22. http://www.sciencedirect.com/science/article/pii/S030146811300087X?via%3Dihub Frank LG (1997) Evolution of genital masculinization: why do female hyenas have such a large 'penis'? Trends Ecol. Evol. 12:58-62. http://www.cell.com/trends/ecology-evolution/abstract/S0169-5347(96)10063-X Frank LG and Glickman SE (1994) Giving birth through a penile clitoris: parturition and dystocia in the spotted hyaena (Crocuta crocuta). J. Zool. 234:659–665. http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1994.tb04871.x/abstract Frank LG, Weldele ML, and Glickman SE (1995) Masculinization costs in hyaenas. Nature 377:584–585. http://www.nature.com/nature/journal/v377/n6550/abs/377584b0.html?foxtrotcallback=true Glickman SE, Cunha GR, Drea CM, Conley AJ and Place NJ (2006) Mammalian sexual differentiation: lessons from the spotted hyena. rends in Endocrinology and Metabolism 17 (9): 349–356. http://www.sciencedirect.com/science/article/pii/S1043276006001767 Holekamp, KE, personal communication. August and September 2017. Muller MN and Wrangham R (2002) Sexual Mimicry in Hyenas. The Quarterly Review of Biology 77 (1):3-16. http://www.journals.uchicago.edu/doi/abs/10.1086/339199?journalCode=qrb
Thanks to spotted hyenas’ unusual social structure, males experience a tough life of solitude, harassment, and deprivation. Thanks also to our supporters on https://www.patreon.com/MinuteEarth ___________________________________________ If you want to learn more about this topic, start your googling with these keywords: Sex role reversed species: a species in which males and females exhibit roles other than what might be expected based on other aspects of their biology and mating systems ___________________________________________ Credits (and Twitter handles): Script Writer: Kate Yoshida (@KateYoshida) Script Editor: Emily Elert (@eelert) Video Illustrator: Ever Salazar (@eversalazar) Video Director: Kate Yoshida (@KateYoshida) Video Narrator: Kate Yoshida (@KateYoshida) With Contributions From: Henry Reich, Alex Reich, Peter Reich, David Goldenberg Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder Video Credits: Hyenas feeding - Kate Yoshida Image Credits: Scarface - Kate Yoshida _________________________________________ Like our videos? Subscribe to MinuteEarth on YouTube: http://goo.gl/EpIDGd Support us on Patreon: https://goo.gl/ZVgLQZ And visit our website: https://www.minuteearth.com/ Also, say hello on: Facebook: http://goo.gl/FpAvo6 Twitter: http://goo.gl/Y1aWVC And download our videos on itunes: https://goo.gl/sfwS6n ___________________________________________ If you liked this week’s video, we think you might also like: A blog by researchers currently studying spotted hyenas in Kenya's Masai Mara: http://msuhyenas.blogspot.com/ ___________________________________________ References: Chepko-Sade, B. D. & Z. T. Halpin. 1987. Mammalian dispersal patterns: the effects of social stucture on population genetics. University of Chicago Press. Chicago, Illinois. Holekamp, K.E. & Smale, L. (2000) Feisty females and meek males: reproductive strategies in the spotted hyena. In Reproduction in Context. K. Wallen and J. Schneider (Eds). MIT Press. Cambridge. MA. Pp. 257-285. Kruuk H. 1972. The spotted hyena: a study of predation and social behavior. Chicago: University of Chicago Press. Smale, L., Nunes, S., and Holekamp, K.E. (1997) Sexually dimorphic dispersal in mammals: patterns, causes and consequences. Advances in the Study of Behavior 26: 181-250. Strauss, E., February 2017, personal communication. Turner, J., June 2017, personal communication. Van Horn, R.C., McElhinny, T.L. & Holekamp, K. E. (2003) Age estimation and dispersal in the spotted hyena (Crocuta crocuta). Journal of Mammalogy 84: 1019-1030. Watts, H. E. & Holekamp, K. E. (2007) Hyena societies. Current Biology 17: R657-R660.
Center for Behavior, Evolution, and Culture - Speaker Series
Patterns of survival and reproduction are known to be influenced by prevailing environmental conditions. In this talk, I will draw from my research on gregarious mammals and birds to examine how the social environment can affect these two components of fitness. First, I will discuss how social status, group size and maternal support influence survival and reproduction in the spotted hyena (Crocuta crocuta), a large carnivore that lives in complex social groups much like those of cercopithecine primates. Second, I will present my recent research investigating the effect of social cues on reproductive timing in the pine siskin (Spinus pinus), a nomadic North American finch with a flexible breeding schedule. Throughout, I discuss what these findings tell us about the evolution of behavior in these species.