Whale Migration Calculator

This calculator starts with real spherical geometry rather than a flat approximation: it computes the Haversine great-circle distance between your breeding and feeding ground coordinates, the shortest possible path along the Earth's curved surface between two lat/long points. Whales don't actually travel that shortest path, though — they follow coastlines, detour around landmasses, and adjust for currents — so the code inflates the great-circle figure by 15% to approximate real-world track length. Travel time then divides that distance by how far the whale covers per day, itself a product of your swim speed and stated hours of active swimming (most baleen whales swim 16-20 hours a day during migration, with rest periods scattered throughout). The energy side of the calculator applies Kleiber's law, a well-established scaling relationship where basal metabolic rate rises with body mass to the 0.75 power rather than linearly — larger animals are more metabolically efficient per kilogram, not less.

Migration is treated as sustained activity at 2.5 times basal rate, a standard multiplier for active metabolism in marine mammals. Total energy cost over the round trip is then converted into kilograms of fat reserves needed, using roughly 9,000 kcal of energy per kilogram of blubber. Because coordinates and swim speed compound multiplicatively through every downstream figure, a wrong sign on longitude (east vs. west) or an unrealistic sustained speed will distort the whole result, not just the distance line.