Photographic gallery — Mammals

A rutting bull bison in his prime pauses in Yellowstone's Little America before wandering off in search of cows.

An early spring frost recorded the comings and goings of raccoons at Volo Bog in northern Illinois.

Their mother having left them, probably to hunt for food, these curious young raccoons peek out of their hideaway along the banks of the Des Plaines River.

This inquisitive goat stopped for a better look at me before continuing on to a mineral lick in the southern end of Glacier National Park.

A young bison calf, with its umbilical cord still attached, scans its new world before hurrying to catch up with its mother.

An adult coyote carrying one of its pups trots toward a new den. The previous den had been underneath a porch of one of Yellowstone's Roosevelt cabins.

Sometimes confused for grizzlies, cinnamon black bears are just a different color of black bear and can often be seen grazing on grass as this one was doing.

A young bighorn ram pauses early one morning before climbing a hill to forage.

After cocking its ears and listening for movement below the snow, a fox leaps in the air and pounces. Having stunned a rodent, it clasped it in its jaws and trotted into the nearby forest to feed.

A mule deer stands motionless with all ears and eyes directed at me.

On a rainy October morning, with hibernation a few weeks off, a black bear feeds on rose hips along the Blacktail Plateau Drive in Yellowstone.

An early snow fell on a bull elk and his harem in the northeast of Yellowstone. The bull was bugling at a rival in a nearby meadow.

A young otter rests for a moment before sliding back into Trout Lake. One of its siblings later became separated and cried loudly from near the outlet before its mother came along and grabbed it by the scruff of its neck.

A sow grizzly crosses the Lamar River one spring evening before taking her two cubs uphill for the night.

A bull moose feeds on aquatic vegetation in Yellowstone's Floating Island Lake one summer evening.

During the epic winter of 2010-2011, many mammals in Yellowstone were pushed to the limits of survival. This moose traveled a creek corridor in northeastern Yellowstone to conserve energy but had to plunge into deep snow to reach the forest to browse.

A curious bison calf lingers to have a a look at people stopped on the road in Yellowstone watching its herd.

A red fox, likely with kits to feed, pauses a moment in northeast Yellowstone before resuming its evening hunting.

Bunched-up elk watch for the return of the Canyon wolf pack near Mammoth Hot Springs on an April morning. The wolves, however, dropped down to the Gardner River and trotted west.

While skiing, I often see weasel tracks zigzagging in the snow but rarely the animals themselves. One memorable winter, I saw several weasels darting near ski trails, including this one caught bounding over a world of white.

While watching a black bear sow and her yearling grazing on grass in Yellowstone, I was surprised by this much bigger bear stepping out from the forest.

A coyote carrying one of its pups leaps over a fast-flowing creek on its way to a new den. Their previous home had been underneath a porch of one of Yellowstone's Roosevelt cabins.

The alpha male of the Canyon Pack (lawfully) crosses the road between Gardiner, MT and Mammoth Hot Springs on an April morning in 2009.

A sow grizzly takes a look around a high meadow near Mount Washburn in Yellowstone.

After watching elk rut in the Yellowstone area for several seasons, it was interesting to see the rut near Cataloochee in Great Smoky Mountains National Park. This bull bugled some, but didn't intend to challenge other males outright. He seemed to be trying to lure a female away but had no luck while we watched.

These pronghorn stopped long enough for a portrait on a mid-winter's day north of Gardiner, Montana. A few moments later, they continued feeding in snow-free patches of grasses.

A shaft of light illuminates a bighorn sheep near Bighorn Peak in the northwest of Yellowstone.

A coyote surveys the landscape for prey on a spring morning in Yellowstone's Little America.

Though much maligned in the West, it's hard to look into the eyes of a coyote and not sense their intelligence.

A pronghorn buck stands amid sweeping grasslands, fit and ready for the coming rut.

A bull bison plods along the road near Yellowstone's Trout Lake during the epic winter of 2010-2011. The plowed road allowed easier travel for many animals during a heavy season of snow. This bull eventually lunged up into deep snow and plowed it with its head to look for dried grasses.

As winter thaws into spring, a group of bighorn rams surveys the landscape in all directions as they move to a new foraging area.

A spring snow shower paints this picture of a bull elk in velvet racing through a meadow from some unseen threat in the forest.

A young bison calf clings to its mother while the rest of the herd grazes nearby.