We recently confirmed that our North American river otter is not pregnant. I’m disappointed.
For reasons not well understood, some river otters do not breed readily in zoos. Our female was born at an AZA-accredited zoo and our male was an orphaned otter found in Florida. Although he is almost twice the size of the female, she is most definitely “the boss,” which might be part of the problem with them conceiving. Another problem may be that since they were introduced so young (1 year old), they may have developed more of a sibling relationship than that of a mating pair.
Since 2007, scientists at Lincoln Park Zoo’s Davee Center for Endocrinology have been monitoring our female’s reproductive-hormone levels. In January of 2009, 2010 and again this year her progesterone levels spiked, indicating one of two things: pregnancy or pseudopregnancy, when females exhibit all signs of carrying young without actually doing so.
Unfortunately it was a pseudopregnancy once again this year. But since this pair gets along so well, we maintain hope that at some point in the future we can welcome river otter pups to Chicago, where we’re used to saying “Wait till next year!”
Curator of Regenstein Small Mammal-Reptile House and Pritzker Family Children’s Zoo Diane Mulkerin