Hi everyone and welcome to our second and final episode on penises! Why are bird penises so strange? Why does the spiny anteater have a four-headed penis? Why don't humans have a penis bone? All great questions that at least at mildly addressed in this episode of Petri Dish!
References:

https://www.jstor.org/stable/3677097
https://royalsocietypublishing.org/doi/10.1098/rspb.2009.2139
https://www.nature.com/articles/news.2009.1159
https://academic.oup.com/icb/article/56/4/694/2198487?login=true
https://www.karger.com/Article/Abstract/515145
https://www.publish.csiro.au/rd/rd01110
https://pursuit.unimelb.edu.au/articles/solving-the-mystery-of-the-four-headed-echidna-penis
https://academic.oup.com/jmammal/article/84/2/673/2373735?login=true
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3560785/
https://www.nature.com/articles/news.2011.148
https://academic.oup.com/icb/article/56/4/630/2198577
https://academic.oup.com/biolinnean/article/98/2/400/2448100
https://www.nature.com/articles/s41585-018-0112-z