Last year so many rodents roamed Norwegian forests that residences were overrun, from mountain cabin attics to house basements. This summer in southern Norway, rodent numbers have plummeted to roughly one-hundredth of what they were just a year ago.
They’re small and almost unnoticeable, until their population explodes. Now recent swings in Norway’s small rodent populations have underscored the importance of these creatures for the health of the entire natural community.
Norwegian researchers claimed that the so-called exercise hormone irisin is merely a myth. Now the discoverers of irisin are fighting back, writing that they have irrefutable evidence that the hormone works in humans.