Bates, Paul J. J.; Ratrimomanarivo, Fanja H.; Harrison, David L.; Goodman, Steven M. (December 2006). "A description of a new species of Pipistrellus (Chiroptera: Vespertilionidae) from Madagascar with a review of related Vespertilioninae from the island". Acta Chiropterologica. 8 (2): 299–324. doi: 10.3161/1733-5329(2006)8[299:ADOANS]2.0.CO;2. S2CID 85825521. Peter J Chenoweth; Steven Lorton (30 April 2014). Animal Andrology: Theories and Applications. CABI. ISBN 978-1-78064-316-8. In Transandinomys talamancae, the outer surface of the penis is mostly covered by small spines, but there is a broad band of nonspinous tissue. [96] Dixson, Alan F. (26 January 2012). Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes, and Humans. Oxford University Press. ISBN 978-0-19-150342-9. Archived from the original on 31 December 2013 . Retrieved 6 September 2013. Echidnas belong to a rare group of mammals that lay eggs, and biologists say that their reproductive systems have more in common with birds and reptiles than with other mammals. Also, the penises of these spiky little creatures have more heads than Cerberus. Male echidnas have four heads at the end of their genitals, but none of them are used for urination (that passes through a cloaca).

As of 2015 [update], a systematic review of 15,521 men, who were measured by health professionals rather than themselves, concluded that the average length of an erect human penis is 13.12cm (5.17 inches) long, while the average circumference of an erect human penis is 11.66cm (4.59 inches). [118] [119] Marsupials a b Anderson, MJ (2000). "Penile Morphology and Classification of Bush Babies (Family Galagoninae)". International Journal of Primatology. 5. 21 (5): 815–836. doi: 10.1023/A:1005542609002. S2CID 9983759. Mammalogy. Jones & Bartlett Learning. 21 April 2011. pp.389–. ISBN 978-0-7637-6299-5. Archived from the original on 26 March 2014 . Retrieved 5 May 2013. A bone called the baculum or os penis is present in most mammals but absent in humans, cattle and horses. Born, E. W.; Gjertz, I.; Reeves, R. R. (1995). Population assessment of Atlantic Walrus (Odobenus rosmarus rosmarus L.). Oslo, Norway: Meddelelser. Norsk Polarinstitut. p.100.Tan, Min; Gareth Jones; Guangjian Zhu; Jianping Ye; Tiyu Hong; Shanyi Zhou; Shuyi Zhang; Libiao Zhang (October 28, 2009). Hosken, David (ed.). "Fellatio by Fruit Bats Prolongs Copulation Time". PLOS ONE. 4 (10): e7595. Bibcode: 2009PLoSO...4.7595T. doi: 10.1371/journal.pone.0007595. PMC 2762080. PMID 19862320. American Institute of Biological Sciences (1977). Whales, Dolphins, and Porpoises. University of California Press. GGKEY:T3BKXB87GHT . Retrieved 8 August 2013. Disclaimer: Administration of ZooRedtube.com is not responsible of any illegal pornography content. a b R. F. Ewer (1998). The Carnivores. Cornell University Press. p.116. ISBN 978-0-8014-8493-3. Archived from the original on 26 March 2014 . Retrieved 23 July 2013.

Voss, R.S (2003). "A new species of Thomasomys (Rodentia: Muridae) from eastern Ecuador, with remarks on mammalian diversity and biogeography in the Cordillera Oriental". American Museum Novitates (3421): 1–47. doi: 10.1206/0003-0082(2003)421<0001:ansotr>2.0.co;2. hdl: 2246/2850. S2CID 62795333. Burns, Eugene (1953). The sex life of wild animals: a North American study. Rinehart . Retrieved 23 July 2013. Rietstap, J. B. (1884). "Armorial général; précédé d'un Dictionnaire des termes du blason". G. B. van Goor zonen: XXXI. Vilené: se dit un animal qui a la marque du sexe d'un autre émail que le corps {{ cite journal}}: Cite journal requires |journal= ( help) Charles A. Long (2008). The Wild Mammals of Wisconsin. Pensoft Publishers. p.341. ISBN 978-954-642-313-9. Archived from the original on 26 March 2014 . Retrieved 23 July 2013. Unlike other squirrel species, red squirrels have long, thin, and narrow penises, without a prominent baculum. [102] [103]Schmitt, V.; Anthes, N.; Michiels, N. K. (2007). "Mating behaviour in the sea slug Elysia timida (Opisthobranchia, Sacoglossa): hypodermic injection, sperm transfer and balanced reciprocity". Frontiers in Zoology. 4: 17. doi: 10.1186/1742-9994-4-17. PMC 1934903. PMID 17610714. a b Anderson, MJ (1998). "Comparative Morphology and Speciation in Galagos". Folia Primatol. 69 (7): 325–331. doi: 10.1159/000052721. S2CID 202649686. Blitz J.; Ploog D.W.; Ploog F. (1963). "Studies on the social and sexual behavior of the squirrel monkey (Saimiri sciureus)". Folia Primatologica. 1: 29–66. doi: 10.1159/000164879.

The most common form of genital alteration is circumcision, the removal of part or all of the foreskin for various cultural, religious, and more rarely medical reasons. There is controversy surrounding circumcision. Verts, B. J.; Carraway, Leslie N. (1998). Land Mammals of Oregon. University of California Press. p.41. ISBN 978-0-520-21199-5 . Retrieved 20 July 2013. William F. Perrin; Bernd Wursig; J. G.M. Thewissen (26 February 2009). Encyclopedia of Marine Mammals. Academic Press. ISBN 978-0-08-091993-5. Archived from the original on 11 October 2013 . Retrieved 28 June 2013. Hoffmeister, Donald F. (2002). Mammals of Illinois. University of Illinois Press. ISBN 978-0-252-07083-9 . Retrieved 22 July 2013. Tim Birkhead (2000). Promiscuity: An Evolutionary History of Sperm Competition. Harvard University Press. p.102. ISBN 978-0-674-00666-9. Archived from the original on 26 March 2014 . Retrieved 23 July 2013.On at least one occasion, a dolphin towed bathers through the water by hooking his erect penis around them. [55] Between male bottlenose dolphins, homosexual behaviour includes rubbing of genitals against each other, which sometimes leads to the males swimming belly to belly, inserting the penis in the other's genital slit and sometimes anus. [56] Perissodactyls Schatten, Heide; Constantinescu, Gheorghe M. (21 March 2008). Comparative Reproductive Biology. John Wiley & Sons. ISBN 978-0-470-39025-2 . Retrieved 23 July 2013.