Reithrodontomys megalotis can be found in open grassy environments throughout the West Coast (2). They have brownish-black dorsal fur with a white underbelly (4). Their tails make up about half of their total length, which ranges from 11.5 to 16.5 cm (4). These mice are rarely seen during the day as they are nocturnal, though can sometimes be spotted during sunrise or sunset (1). R. megalotis have a mostly plant based diet, eating seeds and weeds, while also eating some insects (2). They construct multiple nest out of woven vegetation which are hidden under objects like logs or vegetation (1)(4). R. megalotis can survive off saltwater by concentrating and extracting excess salt through their urine (1)(3).
(1) Brylski, P. (n.d.) Life history account for Western Harvest Mouse (United States of America, California Department of Fish and Wildlife, California Interagency Wildlife Task Group) (R. Duke, Ed.). CA.
(2) Jameson, E. W., Jr., & Peeters, H. J. (2004). Mammals of California (Revised ed.). Berkeley, CA: University of California Press.
(3) Macmillen, R. E. (1964). Water Economy and Salt Balance in the Western Harvest Mouse, Reithrodontomys megalotis. Physiological Zoology, 37(1), 45-56.
(4) NPS. Western Harvest Mouse. (n.d.).
(Photograph) ) © Alice Abela