Side effects of tapeworms

grizzly across river
Click to enlarge then click again

This was a close encounter with a mother grizzly and two cubs on Knight Inlet’s Glendale River. Going up river in our skiff with four guests we met the bears coming down. I pulled the skiff to opposite side of the river to allow them to pass about fifteen meters (yards) away. No we were not in danger, as this seemed to be this family’s routine over a two-week period and they had become accustomed to the ritual. As can be seen toward the end of summer and into fall, bears sometimes shed a type of tapeworm, commonly called the broad fish tapeworm. As this photo shows it can sometimes be seen trailing behind them. Grizzly bears can become infected by the tapeworm from eating raw salmon. The physical effect of bears harbouring tapeworm parasites is insignificant to the bear’s health. This will slightly stress the bear, but generally it is not advantageous for the parasite to kill the host, since that would also result in the death of the parasite. This was the only bear I saw with a tapeworm last summer.