This sustained, big disconnect hasn't shown up so far in research on any other hibernating mammal, says study coauthor Brian M. Barnes, also of UA Fairbanks.
Mammal hibernation matters to human medical research, says physiological ecologist Hank Harlow of the University of Wyoming in Laramie. Relying on mechanisms that scientists would love to understand, black bears spend five to seven months without eating, drinking or taking a single bathroom break. But unlike bedridden or spacefaring people, the hibernators don't lose their muscle strength or bone mass. "Bears are just remarkable," Harlow says.
This Alaska study is the first to manage continuous monitoring of metabolic rate and body temperature throughout bear hibernation in low-disturbance conditions, Tøien says. Other studies based on intermittent sampling with older instruments, indirect evidence or studying bears with lots of people nearby have left the matter "uncertain," as he puts it.
He and his colleagues get such abundant data by volunteering to take in black bears that have developed a taste for foraging close to people and are about to be killed as menaces. "We read about them in the Anchorage Daily News before we get them," Tøien says.