Sydney Anderson

The Grand Mesa of Colorado is a westward extension of the mountains of central Colorado, standing more than five thousand feet above the valleys of the Colorado and the Gunnison rivers. To certain montane mammals the mesa is a peninsula of cool, moist, forest surrounded by inhospitable, hot, dry, barren lowland. Few mammals previously have been preserved or reported from the Grand Mesa. Of the species... more...

INTRODUCTION A person standing on the North Rim of the Mesa Verde in southwestern Colorado sees a vast green plain sloping away to the south. The plain drops 2000 feet in ten miles. On a clear evening, before the sun reaches the horizon, the rays of the sun are reflected from great sandstone cliffs forming the walls of deep canyons that appear as crooked yellow lines in the distance. Canyon after... more...

Microtus montanus reaches the eastern limits of its geographic distribution in Wyoming and Colorado. There the mountains, but in general not the lowlands, are occupied by this species. A certain minimum of moisture may be of direct importance to the mouse and certainly is indirectly important, because certain hydrophytic or mesophytic grasses used by the mouse for food, for protection from enemies, and... more...

Incidental to studies of speciation of North American mammals, made possible by assistance from the National Science Foundation and the Kansas University Endowment Association, a number of bats have been taken beyond the limits of their previously known geographic ranges. Pending the completion of more detailed faunal accounts, these notes are published so that the distributional records will be... more...

Tropical fruit-eating bats of the genus Artibeus reach their northern limits on the lowlands of the eastern and western coasts of México. Recent students have placed the species of Mexican Artibeus in two groups; one includes bats of small size and one includes bats of large size (Dalquest, 1953:61; Lukens and Davis, 1957:6; and Davis, 1958:163). Three of the small species (A. cinereus phaeotis, A.... more...

Since 1952 when Hooper's review of Latin American harvest mice was published, collectors from the Museum of Natural History of the University of Kansas have visited several countries in Central America, and have obtained many additional specimens. Among these we find a new subspecies of Reithrodontomys fulvescens from Nicaragua, significant extensions of known geographic range for several other... more...

INTRODUCTION In the region including Wyoming and Colorado, Microtus pennsylvanicus has been divided into two subspecies: the pale M. p. insperatus (J. A. Allen) inhabits the Black Hills of the northeasternmost part of Wyoming; the dark M. p. modestus (Baird) inhabits extensive areas in both Wyoming and Colorado. Initial examination of Microtus pennsylvanicus revealed that specimens from the Big Horn... more...