When a humpback takes a breath, air rushes out of its blowhole at nearly 300 miles per hour creating a big puff of mist, or blow, that can be seen all the way to the shore. Once you've seen a blow, wait a while and you could be rewarded with a little action. Humpbacks aren't shy about throwing their weight around. They're out there blowing and breaching, tail slapping and singing, mating and tending their young—enjoying their down time like everyone else.

Humpbacks, which are the fifth largest of the great whales, are particularly easy to observe in the wild for their propensity to pop up out of the ocean like surfacing submarines and engage in acrobatic displays. And when they're not leaping or battling for a female's attention, the males are singing. Catch their vocalizations over the underwater hydrophones available on many whale-watching boats. These otherworldly songs are mesmerizing.

These giant mammals have inhabited the Earth for some 54 million years. Descendants of land living mammals, their closest living relatives are hippos. Research shows they lived on land for about 4 million years, then entered the water where they have remained for roughly 50 million years.

Every year like clockwork, humpback whales travel 3,000 miles from their feeding grounds in Alaska to winter in Hawaiian waters. Their numbers are growing by 5-7 percent a year. An estimated 7,000 are expected to pass through the Islands during the high December to April season, most of them congregating in waters less than 600 feet.

They don't eat in Hawaii. That's what they do in Alaska. Here they live off their thick layers of blubber and spend most of their time mating, calving and fattening up their young for the long trip back to Alaska.

Whale watching has become a big draw for people throughout the world. Commercial whale watching trips are available in close to 90 countries and an estimated 11 million people spend at least $1 billion a year for a look. In Hawaii, whale watching is a $15 million industry.

No wonder. These ancient, intelligent creatures, with brains more than four times the size of humans, are a natural phenomenon in a world of artificial solutions.

No one knows exactly why Hawaii is the migratory destination of so many humpbacks, but one theory holds that females return to the place of their birth when it's their turn to breed. Historic awareness may be another factor. Humpback whales, called kohola by Hawaiians, were never actively hunted by whaling fleets in Hawaii. Whalers were after sperm whales found in the Offshore Grounds between Peru and the Hawaiian Islands.

Outside Hawaii, humpbacks were nearly shredded from existence in the years when commercial whaling thrived. Today their numbers are growing, and they're showing up in new locations, such as the mostly unpopulated Northwestern Hawaiian Islands and off the shores of Vancouver Island.

But humpbacks are far from safe. There are countries that sanction whale hunting for scientific purposes. Many whales die each year from ship strikes and net entanglement. And as the humpback population increases and commercial whalewatching gains in popularity, the risk of vessel/whale collisions grows.

In the Hawaiian Islands, humpback whales enjoy a layer of protection not available anywhere else. The Hawaiian Islands Humpback Whale National Marine Sanctuary protects about 1,400 square miles of waters off the Hawaiian Islands. It is the only national marine sanctuary dedicated to whales and their habitat.