Around 11,000 humpbacks—a quarter to a third of the global population, by some estimates—visit Hawaii from November until early May. They migrate here to mate and give birth. Intensely focused on procreation, these marine mammals don't eat and can lose up to a third of their body weight while frisking in warmer waters. Nonetheless, the gray giants remain impressive, reaching 52 feet long and weighing up to 40 tons. That bulk doesn't deter them from spectacular aerial displays of breaching and slapping the surface with their heads, fins, or tails, though! Boat tours like Captain Dan McSweeney's Whale Watch Learning Adventures remain popular, but you can also spot these amazing creatures off the western Kohala Coast or Holoholokai Beach Park, and from campgrounds in Waipiʻo or Pololū valleys.