By Matthew D. Firestone

From the soaring Rocky Mountains and the stark vistas of the southwestern deserts to the icy waters of the North Atlantic and the tropical heat of the Florida Keys, America offers a surprising degree of biodiversity. Indeed, the country is home to a stunning spectrum of unique wildlife that can serve as the focal point of some extremely rewarding travel.

Bull elk in Yellowstone National Park
© Kraig Lieb Lonely Planet Images.

Rocky Mountains

In terms of classic American wildlife, few regions can compare to the Rocky Mountains, home to such iconic national parks as Yellowstone and Grand Teton in Wyoming. Here, vast herds of bison still roam the edges of the plains, much as they have throughout the continent's history. Alongside these hulking beasts, elk, moose and mule deer thrive in large numbers.

This healthy concentration of herbivores also supports a stable population of rare carnivores, including grizzly bears, mountain lions, gray wolves and lynxes. Throughout much of the U.S., catching a glimpse of these elusive animals is a difficult prospect, although both Yellowstone and Grand Teton guarantee some up close and personal viewing. Generally speaking, wildlife can be spotted throughout the year, though it's good to know that animals are most active in the early morning hours.

Mountain goat on rock ledge.
© Carol Polich Lonely Planet Images.

America's Southwest

In the American southwest, the harsh and inhospitable desert ecosystem has given rise to some of the country's most exquisitely adapted creatures. In national parks such as Grand Canyon in Arizona, and Bryce and Zion in Utah, hikers often share the trails with wild burros, first brought to the region by the Spanish conquistadores. In the rocky hills above, agile mountain goats and bighorn sheep clip the sparse vegetation.

The southwest is also home to some remarkable reptiles, such as the diamondback rattlesnake, which can be an incredibly interesting subject to observe – from a safe distance. Another interesting animal is the Gila monster, a venomous lizard that can reach lengths of two feet, and is adorned with intricate and brightly-colored patterns.

Atlantic Ocean

Offshore, the northern expanses of the Atlantic Ocean provide one of the country's best opportunities for viewing the migrations of humpback whales. These majestic creatures, which are over 40-feet long and weigh as much as 80,000 pounds, travel 15,000 miles annually from their polar feeding grounds to their tropical breeding grounds. During this epic journey, pods of humpback whales commonly cruise along the coastlines of New England.

From Bar Harbor, Maine, to eastern Long Island, humpbacks are commonly spotted on whale-watching excursions from mid-spring to mid-fall. Since they are naturally playful creatures, humpback whales are known for their acrobatic breaches. Humpbacks are also anything but shy, and often swim alongside boats, providing ample opportunities for dramatic photos.

Manatees resting with divers.
© Michael Aw Lonely Planet Images.

Florida Keys

Floating in decidedly warmer waters further south, the Florida Keys are an archipelago of nearly 1,700 tropical islands that arc westward across the Florida Straits. The Keys are home to a biologically rich ecosystem that includes John Pennekamp Coral Reef State Park, one of only two living coral reefs in America. Here, scuba divers and snorkelers can interact with a variety of marine life, including sharks, rays, turtles and a wide assortment of tropical fish.

The Keys are also home to a few thousand manatees or sea cows, though numbers are rapidly dwindling due to increased population pressure. However, there are a still a few pockets where you can catch a glimpse of this gentle marine herbivore, which spends most of its life grazing the warm coastal estuaries.

Whether you spend the majority of your time on land or sea, the four corners of the contiguous United States present ample opportunities for wildlife watching.

Bio: Matthew Firestone is a trained biological anthropologist and epidemiologist who abandoned a successful career in academia for a life on the road. When not traveling the world for Lonely Planet, home is a shoebox apartment in the urban jungle that is Tokyo.

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