Bullfrogs have a brain superpower

The brain runs on glucose—a sugar in blood and the body’s main energy source. When that fuel runs out, neural activity falls apart very quickly. But American bullfrogs (Aquarana catesbeiana) have a surprising biological backup. When glucose supplies dwindle, bullfrog brains can rely on another energy source to sustain important neural functions. This energy source is called ketone bodies, and most animals produce these energy molecules in the liver when fasting, starvation, or p