Yellow-bellied Marmot - Marmota flaviventris
In the past 10 days I've had three glorious hikes in the Lakes Basin! Yay!!! Here are some of the mammals I happened to see!
Last week, in an area I had seen marmots in the past, I spotted one sunning on a fallen log! What a surprise! It posed for us for a minute or so and then jumped off the log. A few seconds later it climbed back up! We snapped lots of photos and left quickly, hoping that we hadn't disturbed it too much!
Marmots live alone, in pairs, or in colonies. Colonies consist of one, or more, harems. The harems are comprised of one male, several females and their offspring. Females give birth to 3-8 pups.
Yellow-bellied Marmots are typically very social. Wikipedia states:
"They inhabit areas with rocky outcroppings, meadows, and forest edges, often near rock piles and boulders. They demonstrate social behaviors including the visiting of [underground] burrows, greeting of colony members, and play-fighting. Playing is most common between young, but also frequent between an adult and their young. Marmots communicate with each other through a high pitched whistle. Depending on how sharp the whistle, colony members respond by either observing their surroundings, or returning to their burrows."
They are mainly herbivores and eat a wide variety of plants including grass, seeds, leaves, flowers, and legumes (members of the Pea Family). They will also occasionally eat bird eggs and insects.
Yellow-bellied Marmot - Marmota flaviventris
They are true hibernators, and spend the winter months sleeping in their underground burrows. Burrows can be 5-7 meters deep for hibernation. Their usual burrows are about a meter deep during the summer months. They do not store food for winter. They spend most of their active months eating to accumulate enough fat to survive hibernation, which can last from Sept. to May. Their metabolism, heart rate, respiration rate, and body temperature are all lowered during hibernation.
California Mule Deer - Odocoileus hemionus californicus
Near the aspen grove in the Lakes Basin Campground, my friend Nancy and I spotted a Mule Deer on the trail! It was foraging on the leaves of Bitter Cherry bushes! Deer don't have upper incisors and canine teeth and cannot nip off twigs. They press plant parts (leaves, stems, etc.) between their upper hard palates and their bottom teeth and jerk their heads up to tear them off! They also have small stomachs, so instead of large quantities of low quality forage, they select the most nutritious parts of certain plants that are high in fiber but low in starch. They are ruminantes with four stomachs, in which they ferment plant material before it is digested. This fermented material is then regurgitated, rechewed, and finally reswallowed! They mainly eat the leaves and fruit of shrubs, and the buds of trees. They also eat grasses, flowers, fruits, and seeds in season.
California Mule Deer - Odocoileus hemionus californicus
There are two kinds of Mule Deer in the Lakes Basin, the Columbian Black-tailed Deer and the California Mule Deer. The California Mule Deer have larger ears (20”-22” compared to 8”) than the Columbian Black-tailed Deer. Another way to determine which species you are seeing is to look at their tail. Columbian Black-tailed Deer have a more-or-less solid black tail. The California Mule Deer's tail is only black on the tip, sometimes with a thin strip of black running down the tail.
On the Bear Lakes Trail we also came across a California Mule Deer doe and two fawns! So cool! The following quote about fawns is from northernwoodlands.org.
"Fawns grow rapidly on their mother’s rich milk. By two to three weeks of age, they begin to nibble green vegetation. After a month, they will browse on tree seedlings. At this age, they begin to choose their own bedding sites and twins are reunited. By summer, young deer can outrun most danger, and trail their mother closely. Fawns usually are weaned at two to three months. In early autumn, a fawn’s spotted coat is replaced by the gray-brown winter coat of an adult deer. Female fawns usually stay with their mothers for two years; young bucks leave after a year. A buck fawn can be identified when only a few days old by the two round spots on its head where the antlers will grow."

American Black Bear - Ursus americanus
I saw this bear in the vicinity of the Lakes Basin two weeks ago. It had several long scars and puncture wounds on its face! Perhaps it had been in a fight with a Mountain Lion???
Bears are omnivores, but mainly eat insects, grubs, fruit, berries, roots, twigs, buds, honey, and tree cambium. Occasionally they will eat small to medium-sized mammals and carrion. They range in size from 3'-3'5'' in height, 4'6"-6'2" in length, and 203lbs.-587lbs. in weight. Adults can run up to 30 mph, and are powerful swimmers and climbers! Here in the Lakes Basin, Black Bears don't truly hibernate. They build up fat to live off of in the winter, and spend most of their time sleeping, but may become active if the weather is unusually warm.
California Ground Squirrel - Spermophilus beecheyi
I saw this California Ground Squirrel last year, near where I saw the Yellow-bellied Marmot this year. California Ground Squirrels hibernate in winter, so right now they are eating and bulking up as much as possible. Their diet consists of primarily seeds, including acorns, insects when available, berries, roots, and bulbs. They will also cache some food in their underground burrow. These squirrels are highly adaptable, and live at elevations from 0 - 7,215'! They prefer to dig their underground burrows on the edges of open areas, such as meadows or fields.
Chickaree or Douglas Squirrel - Tamiasciurus douglasii
Another noticeable squirrel is the Douglas Squirrel/Chickaree. They often scold me loudly from trailside trees! Conifer seeds are their main food, but they will also eat fruit, berries, seeds, fungi, bird eggs, flowers, and leaf buds.
They are "scansorial" or adapted to climbing, and their hind legs are double-jointed for climbing up and down trunks! Douglas Squirrels/Chickarees do not hibernate in the winter! They store 100's of cones on the ground, in large caches for winter. They will dig down through the snow to eat the seeds in these stored cones. They do not live underground. In winter, their nests are mainly found in hollow trees, or abandoned woodpecker cavities, 15'-20' above the ground.
Chipmunk - Tamias sp.
There are at least 5 different kinds of Chipmunks inhabiting the coniferous forests of the Lakes Basin. In the field they are very difficult to identify, as they are so close in coloration. Chipmunks are primarily fruit, nut, and seed eaters, but will also eat fungi (primarily truffles), bird eggs, and insects (caterpillars, aphids, termites, ants etc.). They are known for climbing trees and shrubs to find food. They all have fur-lined internal cheek pouches for carrying nuts and seeds. They cache food for winter as they do not hibernate. They sleep most of the winter and awaken periodically to eat. Their nests maybe be in an underground burrow, or in cavities of trees, logs, stumps, or snags.
Golden-mantled Ground Squirrel - Spermophilus lateralis
Golden-mantled Ground Squirrels are not as commonly seen as Chipmunks. Visually they are easily distinguished from Chipmunks, by the lack of stripes on their head. They also don't climb trees and shrubs to get seeds, but prefer to eat them on the ground. In addition to seeds, nuts, fruits, and underground fungi (truffles), they also eat grasses and leaves. Although not as much of an insect eater as a Chipmunk, they will eat them if they are easily available.
The following information about their burrows is from the website at https://vpcrac.org.
"Golden-mantled ground squirrel burrows are located close to or beneath rocks, bushes, trees, logs, and
stumps, although they may be out in the open as well. Burrow openings are inconspicuous as compared to
those of other ground squirrels. Little or no excavated earth is left by the entrances. The openings are two
to three inches in diameter, and often there are two or more openings to a burrow. The entire tunnel
system may be 17 feet long, running, for the most part, about 8 inches deep. The burrow system may
contain side tunnels and a nest chamber lined with shredded grass, bark, leaves, stems, conifer needles, and,
perhaps, paper or cloth."
They also hibernate in these underground burrows in the winter, and live off their stored body fat!
Veronica Lake
The Round Lake Loop Trail
Last week I hiked the Round Lake Loop Trail with my friend Mary. It was a super-clear blue-sky day with a slight breeze. It was the perfect temperature, and no bugs! We passed several beautiful lakes on the 4.5 mile loop trail. It is probably the most popular trail in the Lakes Basin, but that day we had it mostly to ourselves!!! If you haven't hiked it, I'd highly recommend it for its scenic beauty! Here are some of the lakes we saw!
Round Lake
Silver Lake
Long Lake
Big Bear Lake
Primrose Garden
Primrose Garden Hike
A few days later, my friend Nancy and I did our annual hike to the Primrose Garden near Round Lake. It is one of my most favorite areas in the Lakes Basin! Because the "garden" is shaded most of the day, snow can be there even in August! This makes it possible for thousands of wildflowers to be blooming, even when most of the more exposed areas have already dried up.
On 8/4/25, there were two, solid, 4' tall snow banks still in the garden!
The last of the snow
Primula suffrutescens - Athyrium felix-femina var. cyclosorum
A variety of wildflowers bloom in this garden, but the most numerous are the gorgeous magenta Sierra Primroses, with their yellow centers and evergreen leaves. There were thousands of them in bloom! More than we've ever seen before! They grow in close proximity to hundreds of Lady Ferns and sedges that cascade down the mountain side!
Sierra Primrose -Primula suffrutescens
I've seen small groups of Sierra Primroses in other parts of the Lakes Basin, but they're not common. You can imagine our delight when we visit this garden!
Crimson Columbine - Rufous Hummingbird (juvenile)
Aquilegia formosa - Selasphorus rufus
There are also thousands of gorgeous Crimson Columbines growing on the same rock ledge! Rufous Hummingbirds were there feeding on this amazing abundance of late blooming flowers!
Rufous Hummingbird (female) - Selasphorus rufus
These hummers breed north of us, from southern Oregon to southern Alaska, and then return to southern Mexico for the winter. They don't breed in our area. The males can be distinguished by their bright orange heads, throats, bellies, and backs! It was such a joy to be there, perched above Round Lake, in a garden of wildflowers and hovering hummingbirds! How lucky to have been here twice in three weeks!
The view is also spectacular from the garden, and we lingered as long as we could before we headed back home. Another day in paradise, surrounded by incredible beauty! We are SO lucky!
Where should we hike next time? The Old Growth Forest? Deadman Peak?
Hidden Lake? Lincoln Meadow? Jamison Lake?
After 8 years of posting my blog, I've decided that I'm only going to post my blog every TWO weeks. Check back on September 6th for my next natural history blog.
Your questions and comments are always appreciated! Please email me at northyubanaturalist@gmail.com. Thanks!