Less sensitive temperature regulation a key to hibernation-like torpor

Date: November 15, 2016
Source: RIKEN


Some animals can enter a hibernation-like state called daily torpor that reduces the amount of energy needed to survive when food is unavailable. Using a combination of experimental data and mathematical modeling, researchers at the RIKEN Center for Developmental Biology have determined that the largest factor that contributes to daily torpor is reduced sensitivity of the thermoregulatory system. Published in Scientific Reports, the study shows that during daily torpor, the body's compensatory response to lowered temperature is much less than during normal active periods.

Depending on environmental conditions and the availability of food, many animals can slow down their metabolism to save energy. For some animals, this hypometabolism takes the form of seasonal hibernation, which can last weeks to months. Perhaps less well-known, other animals can enter a state called daily torpor in which metabolism is dramatically reduced from several minutes to a few hours.

"While hibernation is associated with the winter season and cold temperatures," notes first author Genshiro Sunagawa, "we were surprised to discover that instances of daily torpor could be induced at temperatures as high as 24°C (75°F), provided mice did not receive food for 24 hours."

Many researchers believe that the mechanisms underlying hibernation and daily torpor overlap to some extent, but daily torpor in particular is still not well understood because the available time for taking measurements is usually very small.

Read on