Biology ETDs

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A field study was conducted during the summer and early fall months of 1964 to collect information on aspects of the natural history of the rock squirrel, Citellus variegatus grammurus. The study was done in Embudo Canyon at the foot of the west slope of the Sandia Mountains (6500 feet elevation) east of Albuquerque, New Mexico. Twenty nine squirrels were live trapped from a study area 350 yards long by 120 yards wide. These squirrels were painted for visual identification, toe clipped for permanent identification, and released at the point of capture. Field observations yielded information on social behavior, food preferences, use of vocalizations, molt, courtship behavior, and appearance of the young. Young rock squirrels were kept in the laboratory to obtain information on subadult molt and growth rates. Four burrows were in satisfactory condition after excavation to yield information concerning burrow construction. Rock squirrels exhibited no food preference other than for reproductive parts of plants rather than vegetative parts. Extensive overlapping of home ranges shows that rock squirrels are not territorial. Four vocalizations were recognized: (1) an utterance of fear, (2) a general alarm call, (3) an anger call, and (4) a defensive or combat call. Molt of adults and subadults is nearly identical. Molt begins over the neck, proceeding anteriorly and posteriorly from this point. Adult molt in the field is completed in about 6 weeks. Subadults in the laboratory required nearly 8 weeks to complete their molt. Courtship behavior is initiated by the male and appears to involve stroking the female’s head and neck. Copulation may occur in the burrow or among the rocks and is not easily observed. Burrows are neither elaborate nor extensive because the bedrock of the boulder-strewn slopes is very near the surface. Young rock squirrels were estimated to be about 10 weeks of age when they first emerged from their burrows. What appears to be a plateau in growth rates of captive young may be premature growth stoppage as a result of confinement, a winter cessation with growth resuming in the spring, or may indicate that growth after this point continues slowly over a long period of time.



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Department Name

UNM Biology Department

First Committee Member (Chair)

James Smith Findley

Second Committee Member

William Clarence Martin

Third Committee Member

Marvin LeRoy Riedesel

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