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Showing papers on "Flying squirrel published in 1974"


Journal ArticleDOI
TL;DR: Spectrophotometric measurements of preretinal absorbance were made on eyes from prairie dogs, western gray squirrels, four species of ground Squirrels, and a southern flying squirrel, indicating that lenses from all species except the flying squirrel absorb significantly in the spectral region from 520 to 440 nanometers.
Abstract: Spectrophotometric measurements of preretinal absorbance were made on eyes from prairie dogs, western gray squirrels, four species of ground squirrels, and a southern flying squirrel. Results indicate that lenses from all species except the flying squirrel absorb significantly in the spectral region from 520 to 440 nanometers. At 440 nanometers, relative preretinal absorbance was greatest for the prairie dogs (1.31) followed in order by the ground squirrels (1.12 to 1.04), the gray squirrels (0.54), and the flying squirrel, which had an essentially transparent lens and cornea (0.08).

36 citations


Journal ArticleDOI
TL;DR: The purpose of this study was to determine the age structure of populations, frequency of pregnancies and parturitions, and the monthly and annual statistics in populations of two species of flying squirrels, Hylopetes lepidus and Pteromyscus pulverulentus, in a rainforest in Johore, the southernmost state in West Malaysia.
Abstract: Little is known about the reproductive frequency, seasonality, and population statistics of tropical rainforest mammals. One nocturnal, arboreal form, the flying squirrel, Hylopetes lepidus, seems to have a superannual periodicity in reproductive activity with periods of reproductive inactivity as long as 17 months. Another species of flying squirrel, Pteromyscus pulverulentus, seems to breed more or less continuously, but only a small proportion of potential breeders are involved at any given time. Population turnover in both species appears to be slow. Litter sizes average 2 in Hylopetes and 1.3 in Pteromyscus. Population turnover, as es- timated from the frequency of pregnancies, gestation period (estimated), and litter size, is 27 per cent that of forest rats in Hylopetes, and 13 per cent of the rate in rats in Pteromyscus. Little is known about the reproductive frequency, seasonality, and popula- tion statistics of tropical rainforest mammals (Harrison, 1952). Arboreal spe- cies are particularly difficult to study, especially the nocturnal ones. In West Malaysia, the arboreal fauna in the rainforests is rich (Harrison, 1966). Of the 20 species of arboreal squirrels that live in the lowlands, 11 are gliders and nocturnal. Most of these have been considered rare. However, search of ar- boreal nest cavities has revealed large numbers of some species of flying squir- rels (Muul and Lim, 1971). Trapping in the same areas has not yielded these species. In most areas trapping has been the usual method of survey, thus the rarity of these species is more apparent than real. The purpose of this study was to determine the age structure of populations, frequency of pregnancies and parturitions, and the monthly and annual vari- ations in these statistics in populations of two species of flying squirrels, Hy- lopetes lepidus and Pteromyscus pulverulentus, in a rainforest in Johore, the southernmost state in West Malaysia. METHODS The study was conducted from July 1968 through April 1972. At first, samples were taken each month, less frequently later. Nests of the animals were located in the daytime by Orang Asli (aborigines). Animals were removed from nest cavities in trees, together with nesting materials. The advantage of nest collections over trapping is that the whole population is represented including the very young, availing statistics on populations that otherwise can be arrived at only indirectly. We were not reluctant to collect large samples of these species because the forest in this area was being timbered and the region was going to be converted into agricultural land. The animals were placed into cloth sacks, euthanized with chloroform, and for related studies they and the sacks were examined for ectoparasites; blood samples were taken and on autopsy, endoparasites were collected. The reproductive tracts were removed and these and all parasite samples were preserved in 70 per cent alcohol. Uteri were examined under 393

5 citations