Thesis (M.S.)--Eastern Illinois University, 1988. / Includes bibliographical references (leaves 15-17).

A study of shrews of the genus Sorex was undertaken at Point Grey, Vancouver, B.C. Trapping commenced in October 1949 and was continued except for brief periods until May 1951. A total of 1296 small mammals, including 670 shrews were obtained during the period. In the laboratory the animals were examined for parasites and condition of the reproductive system. Standard skull and body measurements, and counts of the number of caudal vertebrae were made on all shrews. Complete separation of the two species of shrews reported to be present on the campus ( Sorex vagrans and Sorex obscurus ) was found to be impossible on the basis of these measurements, even when sex and age of the animals were considered. An arbitrary separation of 95 percent of the material based on tail length and length of the maxillary tooth row was achieved. Differences in pelage were apparent, but not sufficient to separate the two species. Intergradation in all morphological features was taken as evidence that the two species are hybridizing to a considerable extent. Some evidence that the breakdown of mechanisms isolating the two populations has not been complete is presented. Hybridization in a local population such as the one studied was not considered a sufficient basis to change the specific status of S. vagrans and S. obscurus. Further study of these two species in other areas where they coexist in the same habitat is indicated. / Science, Faculty of / Zoology, Department of / Graduate

Life history strategies and ecological adaptations of two similar species of shrews (Sorex vagrans vagrans and Sorex obscurus setosus) were examined in southwestern British Columbia in an attempt to understand 1) how they are able to coexist in sympatry, 2) what kinds and degrees of interspecific competition are evident, and 3) how strategic responses to selective pressures differ between species and among habitats. A trap and recapture program allowed the study of population dynamics and individual life histories of the two species in a forest situation where they were sympatric. Standardized snap-trap lines were set through several habitat types to ascertain basic distributional patterns and habitat preferences of each species. Finally, the collection and specimen preparation of extensive series of Sorex vagrans from lowland grassy fields facilitated examination of seasonal and geographic variation in morphology and reproductive strategy. Sorex vagrans and Sorex obscurus share a common life history pattern, several features of which were examined in detail with reference to their adaptive significance. Many adaptations were considered in terms of energy limitations. Both intra- and interspecific territoriality were evident in non-breeding (first year) individuals of each species. Home range analysis, using an elliptical model, reflected the abandonment of territoriality in breeding adults as home range size increased. My conclusions are that strong site attachment and the establishment of territories during the non-breeding time of life serve to ensure the territory holder sufficient food for overwintering. Species distributions and habitat analyses show that, although the two species overlap geographically, competition is mitigated through, habitat segregation at the microgeographic level, with soil type and the associated soil fauna appearing to be significant factors. Sorex vagrans is competitively superior in the relatively richer soils, while Sorex obscurus has the advantage in the more acidic soils. Intraspecific comparison of forest- and grassland-inhabiting. Sorex vagrans reveal basic differences in reproductive strategy. The attainment of sexual maturity in first year females is relatively common in lowland grassland habitat, whereas no such case is documented in forest habitat. The shorter generation, time appears to be an adaptive response to a situation where food-is less limiting and the reproductive season is longer. Ecological strategies and their evolution in forest and grassland populations, and the significance of evolutionary ecology to shrew systematics are discussed in light of the findings. / Science, Faculty of / Zoology, Department of / Graduate

Known for their high metabolism, shrews possess an incessant need to eat high quality foods. This drives much of the biology of shrews and has caused great difficulties when attempting to study shrews using mark-recapture methods. I reviewed the literature and identified potential causes of varied trappability in small mammals. Weather related factors were important in determining activity levels and thus trappability. Social relationships (both inter- and intraspecific) were found to contribute to trappability, in some cases with dominant individuals completely excluding subordinates from traps. Trap type was the easiest factor for a researcher to vary, and thus received most of the attention in the published literature. Sherman, pitfall, and Longworth traps were commonly used, and although pitfall traps are commonly used as removal traps, there is the potential for their use as live traps. The pitfall and Longworth traps seemed the most appropriate for capture of particularly small mammals, especially shrews; however comparisons between these three trap types were confounded by differing methods used for each trap type, and small sample sizes. I tested the relative efficiencies of pitfall and Longworth traps for livetrapping vagrant shrews (Sorex vagrans), and found the Longworth trap to be much more efficient, capturing up to five times as many individual shrews as pitfall traps. I also tested the utility of addition of mealworms as food for shrews, and the effect of increased trap check frequency on the trap mortality rates of vagrant shrews. The addition of mealworms significantly reduced mortality rates, and the addition of one midday trap check, so that traps were not left open for more than 8 h, reduced overall trap mortality rates in mealworm baited traps from nearly 60% (in non mealworm baited traps, checked at 12 h intervals) to less than 10%. Finally, I tested the effect of drift-fences on capture rates of shrews in pitfall and Longworth live traps on riparian and upland traplines. I found no significant differences between the trap types, or between traps equipped with drift-fences, and those without. However, any effect would have been masked by overall low trap success during this experiment.

Known for their high metabolism, shrews possess an incessant need to eat high quality foods. This drives much of the biology of shrews and has caused great difficulties when attempting to study shrews using mark-recapture methods. I reviewed the literature and identified potential causes of varied trappability in small mammals. Weather related factors were important in determining activity levels and thus trappability. Social relationships (both inter- and intraspecific) were found to contribute to trappability, in some cases with dominant individuals completely excluding subordinates from traps. Trap type was the easiest factor for a researcher to vary, and thus received most of the attention in the published literature. Sherman, pitfall, and Longworth traps were commonly used, and although pitfall traps are commonly used as removal traps, there is the potential for their use as live traps. The pitfall and Longworth traps seemed the most appropriate for capture of particularly small mammals, especially shrews; however comparisons between these three trap types were confounded by differing methods used for each trap type, and small sample sizes. I tested the relative efficiencies of pitfall and Longworth traps for livetrapping vagrant shrews (Sorex vagrans), and found the Longworth trap to be much more efficient, capturing up to five times as many individual shrews as pitfall traps. I also tested the utility of addition of mealworms as food for shrews, and the effect of increased trap check frequency on the trap mortality rates of vagrant shrews. The addition of mealworms significantly reduced mortality rates, and the addition of one midday trap check, so that traps were not left open for more than 8 h, reduced overall trap mortality rates in mealworm baited traps from nearly 60% (in non mealworm baited traps, checked at 12 h intervals) to less than 10%. Finally, I tested the effect of drift-fences on capture rates of shrews in pitfall and Longworth live traps on riparian and upland traplines. I found no significant differences between the trap types, or between traps equipped with drift-fences, and those without. However, any effect would have been masked by overall low trap success during this experiment.

Known for their high metabolism, shrews possess an incessant need to eat high quality foods. This drives much of the biology of shrews and has caused great difficulties when attempting to study shrews using mark-recapture methods. I reviewed the literature and identified potential causes of varied trappability in small mammals. Weather related factors were important in determining activity levels and thus trappability. Social relationships (both inter- and intraspecific) were found to contribute to trappability, in some cases with dominant individuals completely excluding subordinates from traps. Trap type was the easiest factor for a researcher to vary, and thus received most of the attention in the published literature. Sherman, pitfall, and Longworth traps were commonly used, and although pitfall traps are commonly used as removal traps, there is the potential for their use as live traps. The pitfall and Longworth traps seemed the most appropriate for capture of particularly small mammals, especially shrews; however comparisons between these three trap types were confounded by differing methods used for each trap type, and small sample sizes. I tested the relative efficiencies of pitfall and Longworth traps for livetrapping vagrant shrews (Sorex vagrans), and found the Longworth trap to be much more efficient, capturing up to five times as many individual shrews as pitfall traps. I also tested the utility of addition of mealworms as food for shrews, and the effect of increased trap check frequency on the trap mortality rates of vagrant shrews. The addition of mealworms significantly reduced mortality rates, and the addition of one midday trap check, so that traps were not left open for more than 8 h, reduced overall trap mortality rates in mealworm baited traps from nearly 60% (in non mealworm baited traps, checked at 12 h intervals) to less than 10%. Finally, I tested the effect of drift-fences on capture rates of shrews in pitfall and Longworth live traps on riparian and upland traplines. I found no significant differences between the trap types, or between traps equipped with drift-fences, and those without. However, any effect would have been masked by overall low trap success during this experiment. / Land and Food Systems, Faculty of / Graduate

Aspects of olfactory, auditory, visual and tactile communication were investigated in five Elephantulus species (E. brachyrhynchus, E. edwardii, E. intuft, E. myurus, E. rupestris) and Macroscelides proboscideus, facilitating comparisons among species and genera. The purpose of this study was to determine whether species specific patterns of communication could be identified in the southern African elephant-shrews. Scent gland structure and location was investigated to determine whether species specific differences existed and to relate gland location to marking behaviour. Prominent scent glands were found in the oral angel, foot pads, anogenital region and tail of all elephant-shrew specIes. Marking behaviours such as sandbathing, digging and anal dragging correlated strongly with sent gland location, but no glandular size and/or structural differences were apparent among the different elephant-shrew species. Species specific differences in marking frequencies did exist among the six elephant-shrew taxa, but were unrelated to glandular development. Choice chamber preference tests indicated that Elephantulus species preferred conspecific odours, with males showing higher levels of discrimination than females . Audible vocalizations and footdrumrning were investigated and compared in the sex elephant shrew taxa. Distinct differences were present in the acoustic repertoires of the southern African elephant-shrew species. Footdrumming showed very clear species specific patterns, and footdrumming characteristics were compared with an existing morphological phenogram to derive a possible path of evolution for footdrumming. Visual and tactile communication were investigated by analysis of frequencies and sequences of behavioural acts. A comparison of male-female interactions of the different taxa showed differences in behavioural frequencies both between males and females of a species, and among the different species. Discriminant function analysis showed clear species specific patterns in the visual! tactile signalling systems of southern African elephant-shrews, and this was more clearly defined in males. Elephant-shrews showed higher levels of aggressive behaviour in interspecific encounters, indicating a possible role of aggression as a premating isolating mechanism between species. However, no differences in aggressive behaviour between allopatric and sympatric malefemale interactions could be discerned. Elephant-shrew males showed high frequencies of submissive behaviour in intraspecific encounters, which may be a strategy to reduce aggression in conspecific females. Species specific patterns of behaviour were found to exist in all three modes of communication investigated, and may all act to some extent as premating isolation mechanisms between species. However, many of these patterns are very subtle and it is suggested that a combination of all sensory modalities act together to form each species' signalling system. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1996.

by Yuk-Yee Tam. / Bibliography: leaves 124-132 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1985

by Tai-Tung Yip. / Bibliography: leaves 191-199 / Thesis (Ph.D.)--Chinese University of Hong Kong, 1985

Shrews previously recognized as Sorex monticolus were classified into two species (one with 14 subspecies, the other monotypic) on the basis of a morphometric analysis of 3610 individuals from throughout their range. Sorex m. neomexicanus has been recognized previously as a subspecies of Sorex monticolus but is recognized herein as a distinct species. This taxon occurs in the Sacramento and Capitan mountains of New Mexico. This region possibly acted as a boreal-forest refugium for S. monticolus-type shrews during the Pleistocene glaciation, and during the warmer interglacial period, after the most recent glaciation, the valleys became too arid for survival and these shrews survived in forested, montane regions of New Mexico. These mountains are sufficiently isolated from other mountainous regions in the state to reduce or eliminate gene flow between these populations of shrews. S. monticolus as defined herein exhibits relatively little morphometric variation. Even among nominate races, the only obvious morphometric variation is a north-south cline in greatest length of skull. There is a general trend of increasing size from south to north. The southern subspecies restricted to isolated mountains (S. m. monticolus and S. m. parvidens) have the shortest skull lengths of all S. monticolus. The subspecies found in the northern coastal and insular areas of southeast Alaska and British Columbia (S. m. longicaudus, S. m. prevostensis, S. m. malitiosus, S. m. insularis, S. m. calvertensis, S. m. alascensis, and S. m. elassodon) have the longest skulls. S. m. setosus, S. m. isolatus, S. m. soperi, S. m. obscurus and S. m. shumaginensis all have skulls of intermediate length. Insular and coastal populations of S. monticolus have longer skulls than the S. monticolus that occupy the mainland. Shrews with long skulls that occur on the mainland (S. m. longicaudus and S. m. alascensis) also occur on some islands, and the mainland portion of their distributions are restricted to a narrow band along the coasts of Alaska and British Columbia. The southernmost subspecies of S. monticolus with short skulls are restricted to small montane islands. The morphometric variation among nominate races is sufficient to warrant continued separation at the subspecies level of all taxa except S. m. calvertensis and S. m. elassodon. Were it not for differences in pelage color, based on my morphometric analysis, S. m. calvertensis and S. m. elassodon should be synonomyzed. / Graduation date: 1994