Exceptionally low daily energy expenditure in the bamboo-eating giant panda

Laid-back bamboo eater Pandas are members of the order Carnivora but are entirely herbivorous, living almost exclusively on bamboo. Unlike most other herbivorous species, however, their digestive tract has not evolved the long twists and turns that facilitate the slower digestion necessary for cellulose-rich plants. Nie et al. measured energy expenditure in both wild and captive pandas, which was extremely low, relative to other mammals. The pandas' thyroid hormone levels are also a fraction of the mammalian norm. Science , this issue p. 171