Energy is the common denominator that
unites all living creatures. Those that succeed
in high-stakes natural competition – like the hummingbird – adapt their activities to the quality and availability of energy. These tiny birds, which have graced the earth for 22 million years, possess the highest metabolic rate of any warm-blooded animal. Even so, like everything that lives, they are able to obtain more energy from their environment than they use, by investing their resources wisely. To conserve energy when food is scarce, they slow their metabolism to a fraction of its usual frenetic pace, maximizing their Energy Return On Energy Invested.