by Walt Anderson
The pawed cast for this week includes some of the most charming of the rodents—chipmunks. Of the 25 species in the US, Arizona has 6, though the most widespread is the Cliff Chipmunk, star of this show. Its range runs from Utah and Colorado down through Arizona in a broad band from the northwest to the southeast and well into Mexico, including a disjunct population near Hermosillo on the coast of Sonora, where they live in the proximity of boa constrictors!
The Baboquivaris are the westernmost of the Sky Islands, and as a biogeographic island, they have not received every potential colonist from the “mainland.” Friends of BANWR come from elsewhere in Pima County and perhaps beyond, but I imagine most can see chipmunks in the Santa Catalinas. Chippies are absent from the Santa Ritas too despite the proximity of other Sky Islands.
The Cliff Chipmunk is only modestly striped compared to some of its brighter cousins. All chipmunks have striped faces, which help distinguish them from the larger Golden-mantled Ground Squirrels, often mistaken for chippies, though they only live in the higher elevations of the northern half of Arizona.
The genus Tamias means “storer,” referring to their cache economy. Expandable fur-lined cheek pouches allow them to hold large qualities of seeds to carry back to their caches or to haul away dirt and debris from tunnel digging.
A bit hyper and “chippy” by our standards, chipmunks actually got their common name from a corruption of an Ojibwa word for “headfirst,” since they can scamper up and down vertical boulders or tree trunks with ease.
Chipmunk chipping incessantly. Despite what Alvin might tell you, chipmunks do not sing Christmas songs, though they do have a variety of calls—chips, chucks, chatters, trills, warbles, even whistles. I enjoy watching chipmunks chipping, with their tails jerking wildly with each note. After an hour of listening to incessant scolding, however, I am ready to change the channel to, perhaps, some lovely bird song.
Classic Cliff Chipmunk with distinct facial stripes but subtle dorsal stripes. They are alert little creatures, as they have to be, as there are plenty of snakes, raptors, and small carnivores that love fresh chippy. I’ve never seen one swimming, so I don’t think you’ll find fish and chippy.
Chipmunks are primarily vegetarian, eating seeds, flowers, nuts, and berries, though they will take animal matter (insects, spiders, worms, grasshoppers, even bird eggs if they can get them). That is especially true of female chippies, who need the extra protein to support the developing embryos and when lactating. Gestation is just 30 days, so the 2-8 newborns are blind and helpless, though they grow quickly and are adult size in 3 months. This chipmunk shows its capacious shopping bags, otherwise known as cheek pouches.
Chipmunks have excellent manual dexterity, easily manipulating seeds or nuts as they eat. They also are fastidious with personal hygiene, grooming their fur carefully and even moistening their paws and rubbing their ears much as a cat does. They are among the fast and the furriest.
In the northern parts of their range, they go into periods of torpor in winter, not true hibernation, but shutting down to a great extent. Then they wake up and eat from their stores. In much of Arizona and Mexico, they are active year-round, even coming out into the snow if there is a chance of finding some fresh groceries. This fur coat may be warm, but it loses its camouflage effectiveness in the snow.
Rodents are the most diverse of all mammalian orders, but they are often persecuted or simply ignored. Chipmunks are unintentional ambassadors for their kind, as to most of us, they are irresistibly cute and charming. We need to look beyond natural animal magnetism, however, and appreciate all the wonderful little things that populate this world of ours. We are just one element in the great flowering of animal diversity, and without the rest of life, we are totally out of context.