There are animals with an odd number of nipples

Today I learned that there are animals with an odd number of nipples.

Opossum Virginia, a small pocket animal from North America, has 13 nipples: 12 arranged in a circle and another one exactly in the middle.

Other species of opossum reach a peak of 27 nipples.

Source: https://northernwoodlands.org/outside_story/article/opossum