A Time of Purging Before Hibernation - UPDATE October 1, 2019

Baylisascaris transfuga is a roundworm that has been reported worldwide in most bear species. It derives nourishment from ingested material in bear intestines. Studies have shown that such parasites are lost prior to denning.Baylisascaris transfugaBaylisascaris transfuga

In my early study here in northeastern Minnesota in the early 1970’s, I found these parasites in scats on September 9, October 6, and October 16. (Rogers, L. L. 1975. Parasites of black bears (Ursus americanus Pallas) of the Lake Superior Region. Journal of Wildlife Diseases 11:189-192.)

On September 28 of this year, we found these two specimens in separate scats of very different appearance, so they are likely from two different bears. The larger is a hair over 16 inches. The smaller is 13 ¼.

If worms are not considered too gross, we might make a little exhibit of this bit of trivia in the hibernation section at the Bear Center. I don’t know of any common name for these other than that they are roundworms.

Thank you for all you do.
Lynn Rogers, Biologist, Wildlife Research Institute and North American Bear Center