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Age. Bulk of fauna ca. 4,855±70 (DIC-591) (Gillespie, pers. commun.), but woodrat middens within the shelter are dated at as 5,550±130 (A-2115), 9,460±160 (A-2116), 10,030±150 (A-2123), 10,500±250 (A-2411), 10,600±200 (A-2139) (Betancourt and Van Devender 1981). Lemmiscus suggested as earlier than rest of fauna (Gillespie, pers. commun. 1981).
General Description. Atlatl Cave is located on the north wall of Chaco Canyon.
The faunal elements listed here are, according to Gillespie (1985), early Holocene (Lemmiscus curtatus) and middle Holocene (Sigmodon hispidus and Microtus ochrogaster). The presence of Sagebrush Vole may indicate that it was able to hang on south of its present range until middle Holocene climatic change extirpated it. Sigmodon hispidus and Microtus ochrogaster are covered here because they are of interest in terms of biogeography and how relatively moderate climatic changes may allow notable geographic range changes.
The Hispid Cotton Rat currently occurs at some distance to the south and east, and the Prairie Vole reaches west only into northeastern New Mexico in our area. Neither makes it even close to the San Juan Basin nor, in northern New Mexico, close to the continental divide that, today, is inhospitable habitat for these rodents. Their presence, along with the occurrences in the middle and late Holocene of the Yellow-faced Pocket Gopher (Lyman 1983), suggest that warm grasslands allowed these taxa to pass over the continental divide. Once west of the divide, a wide area of lowland habitat would have been available.
Lemmiscus curtatus—Sagebrush Vole
Microtus ochrogaster—Prairie Vole
Sigmodon hispidus—Hispid Cotton Rat
Literature. Betancourt and Van Devender 1981; Gillespie 1985; Lyman 1983.
Last Update: 4 Oct 2008