Sciurus alleni, Nelson, 1898

Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Sciuridae, Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona: Lynx Edicions, pp. 648-837 : 747

85.

Allen’s Squirrel

Sciurus alleni

French: Ecureuil dAllen / German: Allen-Hérnchen / Spanish: Ardilla de Allen

Taxonomy. Sciurus alleni Nelson, 1898 ,

“Monterey, Tamaulipas [=Nuevo Leon],

Mexico.”

This species is monotypic.

Distribution. NE Mexico, in SE Coahuila, S Nuevo Leon, W Tamaulipas, and N San Luis Potosi.

Descriptive notes. Head-body 220-254 mm (males) and 220-254 mm (females), tail 217-247 mm (males) and 217-247 mm (females); weight 290-491 g

(males) and 345-510 g (females). Allen’s Squirrel has gray-brown dorsum, suffused with yellow and grizzled with black and gray. Head is slightly darker, with conspicuous white-to-buff eye ring. Sides are shade paler, and legs are grizzled black, suffused with white to buff. Venter is white. Tail is black, sometimes suffused with faint buff or tan and frosted with white. Melanism occurs occasionally.

Habitat. Oak (Quercus, Fagaceae) and oak-pine (Pinus, Pinaceae) forests in montane and coastal plains.

Food and Feeding. Allen’s Squirrel forages on the ground and in the canopy, feeding principally on tree seeds and hypogeous fungi but will also opportunistically eat insects, avian nestlings, and anurans. It will also feed on agricultural crops including corn, oats, apples, tomatoes, peaches, mangos, grapes, and plums.

Breeding. Pregnancy and lactation have been reported in all months but appear most common in late spring. Litter sizes are 1-4 young.

Activity patterns. Allen’s Squirrels are diurnal and active throughout the year.

Movements, Home range and Social organization. Allen’s Squirrels live in natural cavities in trees or dreys of pine needles, leaves, and sticks above 3 m high in the canopy. Individuals usually forage alone and are rarely seen interacting with others at concentrated food sources. Foraging occurs in all canopylevels, with significant time spent on the ground. Allen’s Squirrels rarely vocalize, but when threatened, they utter an alarm call that is a series of chatters and chucks.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Population trend of Allen’s Squirrel is decreasing. A near complete lack of information on ecology, natural history, or threats likely impedes conservation and management efforts; it appears to be vulnerable to deforestation. This large-bodied squirrel is hunted for food or to reduce damage to agricultural crops.

Bibliography. Best (1995¢), Ceballos (2014), Guevara (1998), Jimenez-Guzman & Guerrero-Vazquez (1992), Leopold (1959), Mercado (1985), Thorington et al. (2012).

Figures

84. Collie’s Squirrel (Sciurus colliaer), 85. Allen’s Squirrel (Sciurus alleni), 86. Mexican Fox Squirrel (Sciurus nayaritensis), 87. Red-bellied Squirrel (Sciurus aureogaster), 88. Deppe’s Squirrel (Sciurus deppei), 89. Peters’s Squirrel (Sciurus oculatus), 90. Yucatan Squirrel (Sciurus yucatanensis), 91. Variegated Squirrel (Sciurus variegatoides), 92. Richmond’s Squirrel (Sciurus richmond), 93. Red-tailed Squirrel (Sciurus granatensis), 94. Guianan Squirrel (Sciurus aestuans), 95. Andean Squirrel (Sciurus pucheranii), 96. Fiery Squirrel (Sciurus flammafer), 97. Yellow-throated Squirrel (Sciurus gilvigularis), 98. Northern Amazon Red Squirrel (Sciurus igniventris), 99. Southern Amazon Red Squirrel (Sciurus spadiceus), 100. Guayaquil Squirrel (Sciurus stramineus), 101. Bolivian Squirrel (Sciurus ignitus), 102. Junin Red Squirrel (Sciurus pyrrhinus), 103. Sanborn’s Squirrel (Sciurus sanborni), 104. Tufted Ground Squirrel (Rheithrosciurus macrotis), 105. Central American Dwarf Squirrel (Microsciurus alfari), 106. Western Dwart Squirrel (Microsciurus mimulus), 107. Santander Dwarf Squirrel (Microsciurus santanderensis), 108. Amazon Dwarf Squirrel (Microsciurus flaviventer), 109. Bangs’s Mountain Squirrel (Syntheosciurus brochus)