Eastern and least chipmunks from northern Minnesota were studied in regard to fecundity, age at maturity, timing of reproduction, and changes in the reproductive organs with age and season. A computer program for discriminate analysis was used to determine relative age of the individual animals. Traditional age indicators were used as variables. The result is a measure of the dispersion of the individual animal from a selected control group using all variables at once. Subjective decisions are almost eliminated by this technique. The histology of the reproductive and accessory organs is similar to that of other sciurids as described by other authors. An apparent difference is the presence of two very distinctive areas in the epididymides. The epithelium of one region has central nuclei and is about 31.4 mu. in height. The epithelium of the other area has basal nuclei and is about 16 mu. in height. Sperm is absent from the lumina of the first tubule type, but abundant in the lumina of the second tubule type. The chipmunks in both Oregon and Minnesota had only one breeding season per year which occurred shortly after emergence from hibernation. Hence juveniles do not breed until the spring following their birth. A significant change in ovulation rate of the eastern chipmunk was detected between 1967 and 1968, and for the least chipmunk in Oregon between 1968 and 1969. The rates changed from 7.09 in 1967 to 4.35 in 1968 for the eastern chipmunk, and from 4.78 in 1968 to 6.31 in 1969 for the least chipmunk. Preimplantation loss and resorption of embryos increased in the years of lower ovulation rate. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

Graduation date: 1991

Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 22-25). Also available in electronic format on the Internet.

Observations of reproductive behavior, growth and development of the young, food habits, habitat preference, and daily and seasonal activity patterns of the Colorado chipmunk are presented for the first time. The breeding cycle is as follows: mating occurs in late February or early March; the young are born in early to mid-April and first appear above ground in May, but do not reach breeding age until the following spring. There is only one litter of young per year. The mean number per litter was 5.7 for three litters born in captivity. The sex ratio of the animals born in captivity and animals observed in the field was 1:1. The average weight at birth was 3.05 g and the daily increase in weight was 0.52 grams for 90 days. The eyes were opened 29 to 33 days after birth. The pinnae unfolded in 2 to 3 days and the auditory meatuses opened when 28 to 29 days old. The eruption of the teeth were as follows: the lower incisors appeared in 10 to 12 days, the upper incisors in 20 to 22 days, and the cheek teeth appeared in 34 to 37 days. The dorsal dark and white stripes appeared in 10 days. Colorado chipmunks at Arches National Monument are found in association with juniper-pinyon areas along solid rock ledges with tumbled rock masses at their bases and on higher ridges and ravines where the soil is rocky, and to some extent associated with the blackbrush and Indian rice grass of sandy flats near juniper-pinyon areas. The seeds or fruits of the following plants were most often eaten: Indian rice grass (Oryzopsis hymenoides), Russian thistle (Salsola kali), squawberry (Rhus trilobata), cliff rose (Cowania mexicana), and juniper (Juniperus osteosperma). The chipmunks do not become active until after sunrise and as the temperature increases to its midday maximum the activity of the animals decrease to a midday minimum. The chipmunks are inactive above ground from late November until late February. It is suggested that during this period the chipmunks alternate between sleeping and feeding from their food stores. Juvenile Colorado chipmunks molt twice during their first year and it is suggested that the adults also molt twice each year. The molt proceeds anterior to posterior in June and July and progresses posterior to anterior in the September-October molt.

Cluster analysis of a large body of data on 180 Oregon specimens of Eutamias minimus and E. amoenus suggest that overall length of skull, basal length of skull and length of palate are taxonomically critical. If their sum is less than 71.3 millimeters the animal is E. minimus. If the sum is greater than 72.7 millimeters the animal is E. amoenus. If the sum is between 71.3 and72.7 millimeters, other factors must be considered before the animal can be identified. Of the 180 specimens, there were 60 E. minimus, 114 E. amoenus, 2 hybrids, 2 unidentifiable and 2 mismatched skulls and skins.

Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 32-35). Also available via Humboldt Digital Scholar.

This study describes and analyzes the vocalizations of the Townsend chipmunk (Eutamias townsendii) in Oregon. Tape recordings of calls were collected primarily from Forest Park in Portland (Oregon) during 1970 and 1971, and sonograms of these recordings were produced. Findings were compared with those of Brand (1970) who investigated E. townsendii vocalizations in California. The prominent calls in the vocal repertoire of townsendii are the quist, the quirt, and the chipper. These calls all appear to be warning calls. The quist note is a a chevron-shaped (A) figure representing a sound which begins at a low frequency (1-2 KC), sharply rises to a peak at about 11 KC, and then drops sharply to the lower frequencies again. Quists are arranged into bursts, and bursts into sequences. The number of quists per burst and the frequency of the top of the note decreased significantly over time. The interval between burst increased significantly, while the interval between quists seems to increase over time. The variation in the quist rate and related character6istics between Oregon and California townsendii populations is probably a result of subspecific differences. There seems to be a trend in the sciurids from the specific vocal system (one definite meaning per call) of the forest dwellers towards the unspecific vocal systems of animal groups which live in the more open habitats. E. townsendii displays a specific vocal system in which each call seems to have a specific function.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains ix, 114 p. : ill. (some col.), map. Includes abstract. Includes bibliographical references (p. 92-107).

This thesis describes an investigation of space use in least chipmunks at Kluane Lake, in the southwest Yukon. I examined demography, home range and habitat use patterns in the population. Based on live-trapping data from two grids over two summers, mean number of animals on the study area was 22.6/grid, similar to chipmunk numbers measured there over the previous four years. The population was lower than is generally found in the same species further south, although year-to-year stability was typical. Chipmunks preferred open forest and shrub-land to closed-canopy forest, which is also typical of the genus. Home range sizes measured using telemetry averaged 4.86 ha, higher than in any previously published study of the genus. I examined the relationship between social spacing and space use. Home range overlap averaged 93.4%; chipmunks do not appear to defend exclusive core areas. Provoked interactions among neighbours suggested that social dominance was based on age, weight, and breeding condition, rather than ownership of space. Although provoked interactions were generally aggressive, the telemetry data suggest that such behaviour was artifactual. Comparing the encounter frequency of radio-collared animals to that generated by a random model showed that chipmunks avoided encounters, except when harvesting seasonally abundant food. Grid-trapping did not increase food or cover availability enough to affect home range size. There was evidence that the presence of traps affected use distribution but not enough to invalidate trap-based home range estimates. Comparison of trap and telemetry based estimates of home range size yielded no significant differences. / Science, Faculty of / Zoology, Department of / Graduate