Wallowing Bears

Wallowing is a behavior most notably seen in pigs, however, California black bears, Ursus americanus, regularly use wallows during the summer and early fall.  At a prime wallow, upwards of five bears could visit on a warm day.  A bear wallow is generally about the size of a large bathtub and is usually located in a wet meadow with a high water table.  It is unknown if bears actually engineer the wallows from scratch.

Wallowing is traditionally believed to serve temperature regulation and insect/pest mitigation purposes.  Additionally, due to the high bear traffic at these wallows, the wallows may serve a role in reproduction and social encounters.  Bears will rub themselves on the sides of the wallow and nearby trees, leaving behind scent that is detectable to other bears and can increase the chance of finding a mate.

This bear above is just coming up from a refreshing dunk on a warm day. Please disregard the date stamp on the photos above and below as these were taken in late August of 2011.  The date was incorrect, but the time stamp shows that the second bear came by only 40 minutes after the first.

A lesser known function of the wallow is that under certain circumstances bears come for leisure time. In this video, a mother bear and one of her two cubs become quite playful in a small wallow. The bear cub in this video is rambunctious and wants to play with its fairly aloof mother. The human-like quality from mom is subtle, but if you watch closely at 24 seconds into this video, the mother instigates a mock fight with a simple poke to the soft side of the cub.

In this video, the two cubs play fight and practice skills that will be necessary to survival when they are out on their own as young adults.  To the victor go the spoils and a comfortable wallow all to one's self.

The cubs can occasionally play nice and enjoy the wallow together.

But the truce is not long lived between siblings and the battle picks up where it was left off.

The mother doesn't seem to mind too much and continues with her wallowing.

The mother and her two cubs were the only bears seen at this particular wallow during the week while the camera was here.  The absence of other bears may have been why they were acting so nonchalant and relaxed in the wallow.

Other critters stopped in to the wallow, to drink or cool off.  The black tailed deer, coopers hawk, black tailed jackrabbit, and western grey squirrel all made appearances.

Coon and friends

In the lower reach of Putah Creek a narrow riparian corridor is home to a rich diversity of wildlife.  Although not a Sierran ecosystem, Putah Creek has a similar mammalian fauna.  The habitat is productive and supports high densities of mesocarnivores like the raccoon, otter, skunk and opossum.

The Coon, Procyon lotor, roams at night foraging for a diverse diet ranging from mollusks, fish and bird eggs to fruits, berries and nuts.  They are also common nighttime visitors to trash cans and pet food containers.  Raccoons are crafty mammal who thrive in a wide variety of habitats and niches. 

Though Coon may be the most notorious nocturnal critter of the area, several of his cohabitors can be also seen in the evening and early hours of the morning.  This family of otters, Lutra canadensis, are coming back from an early morning swim, likely with bellies full of crayfish, freshwater mussels and fish. Afterward, they head up to their burrow in the levee to spend the day. They can be seen occasionally near UC Davis with sightings in the arboretum.

Opossums, Didelphis virginiana, are another nighttime scavenger competing for a diet similar to raccoons.  Native to the East coast, opossums have invaded Western ecosystems.  These critters can be commonly seen in the Sierras.  Much like the raccoon, these critters are frequently encountered in the backyards of suburban neighborhoods.

The Striped skunk, Mephitis mephitis, is another nocturnal scavenger.  Skunks forage for roots, downed fruit, and nuts, but relish the opportunity to capture small rodents, insects, and lizards.

The Coon also shares the habitat with herbivores like the black tailed jack rabbit, Lepus californicus,

and granivores like the California quail, Calipepla californica

as well as rodents like the western grey squirrel, Sciurus griseus,

and the deer mouse of the Peromyscus genus.

Big Cat Bridge

This camera set on an old footbridge shows several carnivore species.  A ringtail, Bassariscus astutus, made the first appearance on the first night of the set.  The following day a mother cougar, Puma concolor, with three cubs crossed the bridge in broad daylight.  On day three, another slightly larger cougar crossed the bridge going the opposite direction.  That evening the camera was visited by a striped skunk, Mephitis mephitis, and the ringtail.  A western grey squirrel, Sciurus griseus, visited the bridge on day four and every day for the rest of the two week set.  A young bobcat, Lynx Rufus, crossed the bridge the same day and left a scent marker on the rusty fence post with chicken wire.  Meanwhile, the ringtail visited the bridge every evening for the duration of the set.  In the early morning on day eight the larger cougar returned across the bridge under the cover of darkness.  On day nine an older bobcat crossed the bridge coming from the same direction as the younger bobcat.  The old cat stopped to smell the scent marker left by the other bobcat.  The striped skunk made another appearance during the pre-dawn hours of day fifteen.

Female mountain lion, Puma concolor, with three cubs crossing an old footbridge over the Rubicon River in broad daylight.  Mountain lions are ubiquitously distributed throughout the Sierra Nevada Mountains but are rarely seen.  This was my first time successfully photographing a mountain lion after several attempts.

A larger, lone cougar crosses the bridge heading in the opposite direction the following day after the female and her cubs.

Two different bobcats, Lynx Rufus, crossed the bridge five days apart.  The first bobcat is a young adult.  This bobcat lifts its tail and sprays the fence post leaving behind a scent marker.  An older bobcat comes by five days later and detects the marker from the first bobcat.

The ringtail, Bassariscus astutus, is seldom seen due to its nocturnal and secretive lifestyle.  This ringtail likely has a nest in a cavity in a nearby tree and was a regular visitor of the bridge, showing up every night except the second.  The ringtail has a midden at the center of the bridge which it visits regularly.  This was my first photograph of a ringtail.

The striped skunk, Mephitis mephitis, made two appearances during the two week set.  This picture captured the skunk on alert with the back arched and tail up.

This western grey squirrel, Sciurus griseus, was a common daytime visitor of the bridge. The squirrel made an appearance everyday except for the first two; often several times per day.

Bear Country

Multiple California black bears, Ursus americanus, traveling on a bear trail in the Tahoe National Forest.  These photos were taken after a snow storm in the fall of 2010.