Green and Flinders (1980) summarized pertinent data concerning Brachylagus idahoensis. The Pygmy Rabbit is a small, cottontail-like animal that today is limited primarily to Big Sagebrush (Artemisia tridentata) areas of the Great Basin and eastern Washington. It's nearest approach to our region today is in southwestern Utah (Fig. 1).
Fig. 1. Currant geographic range of the Pygmy Rabbit. Adapted from Green and Flinders (1980).
Its relationship to Big Sagebrush apparently is due to dependency. Up to 99% of its winter food consists of this shrub. Big Sagebrush remains important in summer, but grasses can make up 30-40% of its diet in mid and late summer (Green and Flinders 1980). It appears to prefer tall, dense clumps of sagebrush. This close association of Artemisia tridentata and Brachylagus implies similar vegetation at least as far south as Lake San Agustín and Isleta. Some other taxa indicate sagebrush-grassland into southern New Mexico; absence of Brachylagus in those areas suggests either sample error or that the sagebrush-grassland in the south differed in some important way from that farther north.
Fig. 2. Right dentary of Brachylagus idahoensis from Isleta Cave No. 2 (top) compared to Sylvilagus audubonii (modern specimen), the smallest of the regional Sylvilagus.
Fig. 3. Comparison of the humerus (left) and femur (right) of Brachylagus (left member of each pair) and Sylvilagus. Scale in mm.
Rancholabrean: Pit Stop Quarry (Murray et al. 2005)
Mid Wisconsin: Screaming Neotoma Cave (Glennon 1994: cf.)
Late Wisconsin: Isleta Cave No. 2 (Harris 1993c); Lake San Agustín (Morgan and Lucas 2005); Screaming Neotoma Cave (Glennon 1994); Sheep Camp Shelter (Gillespie 1985).
Late Wisconsin/Holocene: Tule Springs (Mawby 1967: ? gen. et sp.).
Literature. Gillespie 1985; Glennon 1994; Green and Flinders 1980; Harris 1993c; Mawby 1967; Morgan and Lucas 2005; Murray et al. 2005.
Last Update: 10 May 2013