The weightlessness of being is only the most obvious facet of an orca’s existence that distinguishes it from what man and his fellow primates experience. Even though they weigh thousands of pounds (tonnage that would render them slow and ponderous as land mammals, as it does elephants and whales’ long-distant cousin, the hippopotamus), a whale’s daily life is spent in a state of gravity-free seawater, buoyed especially by the lungs that are the legacy of having evolved from land mammals. This state almost certainly played a role in the evolution of whales as the largest creatures ever
