Abert’s squirrels (Sciurus aberti aberti), getting fat on gambel oak acorns, in the Coconino National Forest, Arizona.
These are tasseled squirrels, though all of these have shed their distinctive tufts of ear fur for the summer. Winter coats will begin to thicken in just a few weeks.
When I was at university I took a course in bio-geography with Robin Andrews, now Professor Emerita of Biological Sciences at Virginia Tech. Abert’s squirrels figured prominently in one of the key topics of that course. These squirrels are now estranged from their famous cousins, the Kaibab squirrels (S. aberti kaibabensis), found only on the northern Kaibab plateau in the Arizona strip. As the gap of of the Grand Canyon grew over millions of years it separated squirrels on the north and south canyon rims, and the isolated populations became morphologically distinct. For a time they were deemed separate species, now only subspecies, but the evolutionary process of divergent speciation due to isolation and habitat diversification is clearly taking place.
The squirrel in the center photo is striking a languid (but alert) pose I have frequently observed when the squirrels first become aware of my presence. My guess is they are trying to disguise themselves as bumps on the tree limb. If I continue to approach they then climb to a higher branch. Without exaggeration, I have shot hundreds of blurry photos of them making escape to the treetops.
And a final note: It seems sadly unfair that evolution would provide these animals with a means of losing ear fur, when I am at an age when bushy coarse hairs (I call ‘em Brezhnev Brows) appear on my ears and eyebrows, seemingly overnight.
Earthstar mushroom (Astraeus hygrometricus), on the Lower Oldham Trail in the Coconino National Forest, Arizona.
This mushroom has an ectomycorrhizal association with the ponderosa pines it grows near, extracting nutrients from soil that benefit the trees, and obtaining carbohydrates from the pines’ roots to support its own growth. The mushroom is also a food source for Abert’s squirrels, which aid in distributing the mushrooms at the base of the pines in which they live, in a lovely and complicated web of mutual interaction.
Unidentified ugly caterpillar, on the Lower Oldham Trail in the Coconino National Forest, Arizona.
I think this might be the larvae of a buck moth, in the Saturnidae family. Adult buck moths are as beautiful as their larvae are hideous. The adult stage of this caterpillar must be beautiful indeed.
Please click photo for an enlarged (but ugly) view.
Walnut Canyon was settled about 1400 years ago by ancestral puebloan people called the Sinagua. They built cliff dwellings and granaries in the overhanging sandstone walls of the canyon - hundreds of feet over the canyon floor. At its peak the community here was home to about 600 people. The site was abruptly abandoned, probably during a period of food scarcity that coincided with extended drought.
The cliff face rests on a distinctive layer of sandstone called the Toroweap formation (center photo). Its textures and sculpted surface reveal that it was formed from ancient sand dunes that covered the Colorado Plateau region between 300 and 250 million years ago.
The bottom photo shows crews working to restore the trail at Walnut Canyon National Monument. The trail was originally built by the Civilian Conservation Corp during the Great Depression.
Rockmat (Petrophytum caespitosum), at Walnut Canyon National Monument, Arizona.
Please click any photo in the set for full views.