The opossum, the only marsupial in the United States, often has thirteen nipples. It has so many because it can give birth to up to twenty young at once, and only those that receive milk survive.

Art and fact by Kirsten Sheehy, 
Twitter @1010sheehy  

[Edited by Nicole Rodrigues]

Reference:

Marable, A.D., & Smith, M.D. (2022, July 18). Virginia Opossum: Our Only Native Marsupial. extension Alabama A&M & Auburn Universities. https://www.aces.edu/blog/topics/forestry-wildlife/virginia-opossum-our-only-native-marsupial/