How far do whales migrate and why?

The answer

Gray whales migrate roughly 10,000 to 12,000 miles round trip annually between their Arctic feeding grounds and warm-water breeding lagoons in Baja California, Mexico. Humpback whales travel comparable distances between polar feeding areas and tropical breeding waters. Whales migrate primarily because cold, nutrient-rich polar waters are ideal for feeding on krill and fish, while warm tropical waters offer protection from predators for calves and reduce heat loss in newborns that lack thick blubber. Scientists track these journeys using satellite tags and photo identification of unique tail fluke patterns.