Living on the Edge

Nectar-feeding bats are the fastest mammal at burning up body sugar

• Hannah Schardt
• Oct 01, 2007

NECTAR-FEEDING BATS have metabolisms any supermodel would envy: They burn sugar faster than any other mammal, including the most highly trained human athletes. But off the catwalk and out in nature, this may not be such an asset, according to a new study, which finds that long-tongued bats (Glossophaga soricina) live life on an "energetic knife edge" and are extremely susceptible to changes in their environment.

German and Scottish researchers discovered that the bats--among the smallest mammals in the world, weighing less than 10 grams--use the sugary nectar that makes up their diet "within minutes after drinking it." They also found that the bats deplete 60 percent of their meager fat stores each day, barely enough to sustain them when nectar is absent. This leaves them uniquely vulnerable to any ecological disruptions--even those that last only a very short period.