08 October 2023

Food for bears

Biologists estimate about 200 [grizzly] bears each year feast on moths in the eastern portion of the carnivores’ range. Each gram of moth offers bears about eight calories, which means some bears will eat up to 40,000 a day.

A bear could, in about a month’s time, get one-third of the calories they need to build up fat for hibernation at these moth sites,” says Frank van Manen, leader of the interagency grizzly bear study team with the US Geological Survey...

At a time when other food sources, such as whitebark pine nuts and cutthroat trout, have been hit by global heating, disease and invasive species, the army cutworm moth population has remained remarkably stable, making it a critical ingredient in the grizzly bears’ continued recovery in the US...

Researchers believe the army cutworm moth population remains healthy, and because they arrive from many locations as far east as the Missouri River and as far north as the Northwest Territories, no localized issue, such as pesticide use or flooding, can crash their populations..."
The story continues at The Guardian.  I was surprised at the long distances these small moths migrate.

2 comments:

  1. I am sure the bears are not picking them up and eating them one by one? There must be clumps? Where do you even find that many months (tens of thousands) to make it worthwhile eating them?

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