When you think of Mexico travel, what comes to mind? Commercialized beach resorts with ginormous margaritas and mariachi players? One of the world's largest, most populous and most polluted cities? How about wildlife?
Chances are, most people think of Mexican "wildlife" as what goes on in crime-ridden border towns -- yet the fact is that the vast bulk of Mexico is safe and welcoming for tourism -- and holds plenty to captivate travelers seeking peaceful encounters with the natural world.
Four wondrous nature adventures reveal a wild side of Mexico that few travelers experience:
Swimming with Whale Sharks
Off the Yucatan coast, far from the tourist crush of Cancun, lies idyllic Holbox Island. While the tiny island itself offers a placid vacation respite, it's what lies in the waters beyond that is the real attraction: docile whale sharks -- and the opportunity to swim and snorkel alongside them! Not actually whales at all, these are the world's biggest fish, stretching to 45 feet long and weighing up to 15 tons. Whale shark ecotourism adventures take guests offshore by boat to reach the whale sharks where they gather to feed each summer. Then, it's into the water to snorkel with these enormous, amiable creatures, accompanied by expert naturalists. Don't forget your underwater camera!
Sea Turtle Conservation
In late August and September each year, a remarkable spectacle happens on Mexico's southern Pacific coast near the small town of Huatulco: thousands of endangered olive ridley sea turtles come ashore after a life at sea to lay their eggs in the sand. The phenomenon is called an arribada (Spanish for "arrival"), and it happens on just four beaches worldwide. By the light of the moon, the baby hatchings scurry into the ocean, and guests on a conservation-focused sea turtle adventure are on the scene to assist, protecting the tiny turtles from poachers and predators. Alongside biologists at La Escobilla turtle camp, visitors learn in depth about sea turtles and participate in efforts to sustain them.
Mystical Migrating Monarchs
In the highlands of Michoacan one of the planet's most amazing natural phenomena occurs, the annual migration of up to 300 million monarch butterflies. These delicate insects set flight on a remarkable 3,000-mile journey from the northeastern U.S. and Canada to their ancestral wintering grounds in the volcanic mountains of central Mexico. The location of their breeding grounds in a few remote tracts of fir forest remained a mystery until 1977, and how an infant generation of butterflies finds it anew each autumn is still an enigma. Join a small-group adventure to the Kingdom of the Monarchs, where you'll hike and ride horseback into the butterfly sanctuaries. Accompanied by naturalist guides, listen for the hum of millions of vibrating wings, and watch as the flocks take flight in a great swirl of orange. 
The Great Gray Whales of Baja
The Pacific gray whale migration from Alaska's Bering Sea to the warm waters of Baja is the longest mammal migration on earth. Each spring, hundreds of them return to traditional birthing and breeding grounds in the sheltered waters of San Ignacio Lagoon and Magdalena Bay along the Pacific coast of Mexico's Baja Peninsula. Friendly and engaging, they are often intrigued with humans, swimming right up to the side of small skiffs where visitors can frequently approach them at close range. For the most intimate whale encounters, join a Baja whale-watching expedition that enjoys exceptional isolation and proximity to the grays from waterside "whale cabanas" on San Ignacio Lagoon.
By Wendy Worrall Redal
Editorial Director, Natural Habitat Adventures