Yucatán Squirrel, Sciurus yucatanensis

Yucatán Squirrel, Sciurus yucatanensis. Photograph taken in Cancún, Quintana Roo, March 2021. Photograph and identifications courtesy of Marina Sutormina, Stockholm, Sweden.

The Yucatán Squirrel, Sciurus yucatanensis, is a member of the Sciuridae Family of squirrels, chipmunks, marmots, and prairie dogs. The Sciuridae Family consists of two hundred eighty-six species placed in fifty-eight genera. There are twenty-eight species in the Sciurus genus. The Yucatán Squirrel is divided into three subspecies, all of which are found in southeast Mexico. They are also referred to as the Campeche Squirrel and the Yucatán Gray Squirrel. In Mexico, they are known as Ardilla de Yucatán.

Yucatán Squirrels are medium-sized and covered with thin, coarse, and stiff pelage. Their dorsal side is grizzled black and gray with additional yellow to buff tinges. Their ventral side varies from dirty white, through a grizzled yellowish-gray, to black. They have a relatively long, full tail that is black in color with a wash of white dorsally. Ventrally, their tail has a medium stripe of dull-gray or black that is edged with white. Their face is short and broad with a buff-colored patch above their nose. The sides of their head are mainly black. They have pointed and tufted ears that are gray, brown, and white in color, turning off-white during the winter months. They measure between 20 cm (7.9 inches) and 32 cm (13 inches) in snout to vent length, with a 19 cm (9 inches) to 27 cm (11 inches) long tail. On average, they weigh between 341 g (12 oz) and 475 g (17 oz). This species does not display obvious sexual dimorphism.

Yucatán Squirrels are diurnal and primarily arboreal. They are timid and shy, but may be observed moving through the canopy in the early morning or resting on a branch during the heat of the day. They occupy small home ranges and do not migrate. Reproduction occurs year-round and is polygynandrous, with both females and males having multiple mates. Females construct leaf nests on the highest branches in the canopy, where they give birth to two to four young during the dry season. Their lifespans are unknown. Their diet primarily consists of soft fruits, nuts, and seeds. When these foods are not available they consume flowers, buds, and shoots. In turn, they are preyed upon by various birds of prey, feral cats and dogs, coatis, primates and snakes. They rely on their cryptic coloration for defense. The Yucatán Squirrel is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Yucatán Squirrel may be confused with Collie’s Squirrel, Sciurus colliaei, and the Variegated Squirrel, Sciurus variegatoides, due to their similar appearances and habitat. Collie’s Squirrel has a creamy white ventral surface (occasionally light orange), and is native to the western coast of Mexico in the states of Sonora, Chihuahua, Sinaloa, Durango, Nayarit, Jalisco, and Colima. The Variegated Squirrel has a shiny dark gray pelage with a buff orange ventral surface, and occurs from south Chiapas, Mexico to Panama.

From a conservation perspective the Yucatán Squirrel is currently considered to be of Least Concern due to their wide distribution, presumed large population size, occurrence in a number of protected areas, and tolerance to some degree of habitat modification. No major threats have been identified for this species. In some areas, they are hunted for meat and pelts or kept as pets. Local populations may also be threatened by habitat loss and fragmentation due to deforestation.