Squirrely Little Denizens of the Ponderosa Pines

SHY Sprites of the Ponderosa Pine Forests Don't confuse the tassel-eared squirrel with a treetop rabbit or donkey

In a recent visit to the Grand Canyon's North Rim, I couldn't help but overhear an excited visitor telling a park ranger, "I just saw an animal that looks like it's half rabbit and half squirrel."

Laughing, the ranger told him, "This is your lucky day. That's a Kaibab tassel-eared squirrel, and this is the only place in the world where they exist."

Tassel-eared squirrels, one of the showiest of North American squirrels, have conspicuous tufts of long hair on their ears, especially during the fall and winter months. The two best-known variations of Arizona tassel-eared squirrels are the Abert and the Kaibab.

The more widespread Abert squirrel has dark ear tufts, a gray body with a rusty stripe down its back, a white underside and a gray and white tail. It lives in the ponderosa pine tree forests of the Colorado Plateau, from the South Rim of the Grand Canyon to the Mogollon Rim. Aberts also live in some isolated mountain ranges to the south, including the Santa Catalina Mountains near Tucson.

Kaibab squirrels-darker gray or black, with black undersides and Bright white plumelike tails-became separated from the Abert during formation of the Grand Canyon. Isolated on the Kaibab Plateau, the squirrel developed its own distinctive coloring.

Exotic ears count as just one of the differences between tassel-eared and other types of Arizona squirrels. Because they depend so completely upon ponderosa pine trees for survival, tassel-eared squirrels are found only in pine forests atop Arizona's highest peaks, from 5,000 to 9,500 feet.

Ponderosa pine trees provide the major part of the squirrels' diet in the form of pinecone seeds, buds and the inner bark of small twigs. Although they supplement their diet with acorns, mistletoe and mushrooms, the squirrels rely on the pine's inner bark to sustain them through long winters, when other food sources are not available.

Tassel-eareds are picky about their trees. Ponderosas may look alike to us, but to the squirrels, as connoisseurs of fine pines, certain trees taste better than others. They may turn up their noses at one tree, but dine enthusiastically on the one next to it. The reason? Some pines contain higher levels of bitter chemicals called monoterpenes, while "Feeder trees" have a sugary inner bark. Building their nests in nonfeeder trees ensures that the neighbors won't be munching their nest tree for breakfast.

Even these squirrels basketball-size yearround homes are built of ponderosa twigs and cones. The waterproof nests sport cozy linings made of anything handy-shredded bark, moss, fur, feathers, even a pilfered woolen sock. In years of average rainfall, the females give birth to litters of two to four during June or July, though new research has shown that in periods of severe drought like the Southwest has experienced recently, squirrels do not breed at all. By their sixth week, the babies have changed from naked, blind and helpless to furry, bright-eyed and adorable. These squirrels are quick and agile. In late summer near Alpine, I watched an Abert make heart-stopping leaps, high above the forest floor. As she swung gracefully from her nest tree to another pine, and then to another, she was followed by a smaller, juvenile version of herselftheir beautiful tails streaming out behind them.

Tassel-eared squirrels relish truffles not the candy ones made out of chocolate and confectioners' sugar, but the underground mushroom variety. Together, in fact, the ponderosa pines, the truffles and the squirrels enjoy a symbiotic relationship that ensures their mutual survival.

According to Joseph Hall in his book Linea: Portrait of a Kaibab Squirrel, truffles attach themselves to ponderosa pine rootlets with tiny, threadlike extensions.

The fungi help transfer nutrients and water from the soil to the tree, while absorbing carbohydrates and amino acids from the tree's root tissues. But beneath the forest floor, the fungi have no way to disperse their spores. When a squirrel digs up and nibbles a truffle, the fruiting body of the fungi, the spores pass through the animal's digestive system to be scattered about the forest. Next time you're in ponderosa pine country, watch for tassel-eared squirrels. Unlike red squirrels, which chatter from the treetops until you leave their territory, shy tasseleared squirrels are not easy to spot. They'll silently peek at you, like pointy-eared woodland sprites, from the safety of a high tree branch. Hearing comments from individuals who have never seen one before can point you in the right direction. As one camper near Alpine said to photographer Marty Cordano, "I just saw a squirrel with ears like a donkey." AH