Elevation is the determining factor in locating and identifying the variety of plants and animals found in Rocky, and the park can easily be divided into three main zones: the montane ecosystem, at lower elevations; the subalpine, at the midlevels; and the alpine, at the park's highest elevations. The lines between the zones can be a bit fuzzy, and both plants and animals will cross boundaries at times. In addition, across these zones there are riparian areas, which are the wetlands adjacent to rivers, streams, and marshy areas. Within the 415 square miles (265,727 acres) protected by the national park are 17 mountains above 13,000 feet. Elevations in the park range from a low of about 7,840 feet above sea level at the Beaver Meadows Visitor Center to 14,259 feet at the top of Longs Peak.

Montane Zone -- In relatively low areas, usually below 9,000 feet, such as the areas near the Beaver Meadows Visitor Center, at Sprague Lake, and along the Gem Lake Trail, ponderosa pine and juniper cloak the sunny southern hillsides, and Douglas fir blankets the cooler northern slopes. The thirstier blue spruce and lodgepole pine cling to stream sides, where you will also find willow and cottonwood and the occasional grove of aspen. Wildflowers found here include larkspur, fairy slippers, western wallflowers, snowberries, and several types of daisies.

The warmest part of the park, because it is at the lowest elevation, the montane ecosystem has the greatest variety of wildlife. Elk and mule deer browse on sagebrush and bitterbrush, while Abert's squirrels dine on the ponderosa pine's seeds and twigs, and chickarees, also known as pine squirrels or red squirrels, harvest the seeds of the lodgepole pine. Coyotes and badgers frequent the open meadow areas, hunting squirrels and mice, and there are muskrats and beaver in the areas along streams and lakes. Watch for colorful mountain bluebirds, among the earliest of the park's seasonal residents to arrive, as well as the distinctive red-napped sapsucker, western tanagers, black-billed magpies, and warbling vireos, which can sometimes be heard singing from their nests in aspen trees.

Subalpine Zone -- This sector lies between 9,000 feet and 11,500 feet elevation, such as the area around Bear Lake, at Glacier Gorge Junction, and near the Longs Peak Ranger Station. Forests of Engelmann spruce, subalpine fir, and limber pine dominate the landscape, interspersed with broad meadows that are vibrant with spring and summer wildflowers, including silvery lupine, shooting star, and Colorado columbine. In the lower sections of this zone, you'll also see aspen and lodgepole pine, especially where there has been a fire or some other disturbance to the forest.

Among the wildlife to watch for here are deer and elk, which graze on meadow grasses; beavers, which dine on aspen and other trees along the edges of lakes and ponds; chipmunks; and chickarees. Birds seen frequently in the subalpine zone include northern goshawks, Clark's nutcrackers, ruby-crowned kinglets, and both gray and Steller's jays. While most of these animals are found in other zones as well, the subalpine zone is the best spot to see the snowshoe hare and, perhaps, an elusive black bear.

The space between 11,000 feet and 12,000 feet, just below the tree line, is a transition area where trees called krummholz, a German word meaning "crooked wood," are found. Here the trees, predominantly spruces and firs, grow very slowly and are stunted and deformed from the harsh, near-alpine conditions. Winds here are so ferocious that branches will often grow only on the trees' downwind side, giving them the appearance of banners or flags. The phenomenon is readily apparent as you enter this area on Trail Ridge Road.

Alpine Zone -- Above 11,500 feet the trees become increasingly gnarled and stunted, until they disappear altogether. This is the alpine tundra. Tundra is Russian for "land of no trees," and fully one-third of the park is in this bleak, rocky world, where many plants are identical to those found in the Arctic.

Despite a short growing season of only 6 to 8 weeks, a variety of hardy plants survive here -- some 200 varieties -- most remaining small and clinging low to the ground for a bit of warmth, and to avoid being shredded by winds that routinely exceed 100 mph. Many tundra plants contain the chemical anthocyanin, which converts sunlight to warmth, and some plants, such as the alpine sunflower, grow tiny hairs as protection from the elements.

Low grasses and sedges grow here, providing food for deer and other animals. You'll have to look carefully to see some of the alpine tundra wildflowers; their white flowers blend in with the patches of snow that remain in August. These hard-to-spot blooms include the Arctic gentian, Alpine lily, and alpine sandwort. Other species brighten the tundra during its short summers, including the purple fringe, deep-red king's crown (also called roseroot), purple sky pilot, blue alpine forget-me-nots, and golden draba, a member of the mustard family.

Animals that inhabit the alpine tundra include pikas, members of the rabbit family; yellow-bellied marmots; white-tailed jack rabbits; and northern pocket gophers, a favorite snack of coyotes and weasels. This area is also home to bighorn sheep, which have become a symbol of the park, and it is estimated that more than 200 elk -- about one-third of the park's elk population -- live in the alpine zone year-round. During the summer, birds to watch for include golden eagles, hawks, falcons, and white-tailed ptarmigans. Occasionally, a mountain bluebird also finds its way here.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.