Authors: Ronald Altig And Alan Channing

Authors: James R. Dixon , A. Alberto Yanosky And Claudia Mercollf

Authors: Mark T. O'shea And Andrew F. Stimson

Authors: Trevor J.C. Beebee , L. Vincent Fleming and David Race

Authors: Razi Dmi'el , Gad Perry, Ann Belinsky And Ralph A. Ackerman

Abstract: We studied the effects of incubation substrate and its water content on egg water uptake, incubation duration, and hatchling mass in the diced water snake Natrix tessellata. Egg water uptake was highest in sand (the substrate with the highest thermal conductivity) and lowest in air (which had the lowest thermal conductivity). Water uptake was independent of initial egg mass. Incubation duration was correlated with substrate type and water content. Hatchling mass was independent of initial egg mass, but there was a weak negative correlation with total water uptake and with length of incubation. Wet mass of hatchlings incubated in air was greater than those incubated in sand or vermiculite. A greater increase of water uptake by eggs incubated in the most thermally conductive substrate (moist sand) suggests transport of water vapour, rather than liquid water, as the mechanism of transport across the membranes of parchment shelled eggs.

Authors: E. H. W. Baard' And P. Le F. N. Mouton

Authors: Sebastiano Salvidio

Abstract: The biology of a Speleomantes ambrosii population inhabiting interstitial habitats was studied during two consecutive years in north-western Italy. Surface activity was highest in late spring and early foll and was positively correlated with monthly rainfall. The population structure was analysed on the basis of polymodal size frequency distributions. S. ambrosii demographic structure was composed of two juvenile size classes and a mixed component in which subadult and reproductive salamanders were present. Males bernme sexually mature when >50 mm and females when >58 mm SVL. Estimated age at first reproduction was 3.5 years for males and 5 years for females. Juvenile growth rates. during the first two years of life, ranged from 10 to 13 mm/yr.

Authors: F. Wood And J. Wood

Abstract: Growth of the captive-reared green sea turtle, Chelonia mydas, fits a logistic by weight growth equation reaching an asymptotic weight at approximately 12.5 years with an average weight of I 56 kg. The relationship of weight to carapace length and width is inter-dependent with age and size of the turtle. Mean age at sexual maturity for the captive green turtle is estimated at 16 years, and it is projected that 96% of a captive population would begin nesting at 25 years of age. Although growth of mature green turtles reaches an asymptote at 1 2.5 years, captive, mature green turtles continue to increase in weight at a rate of 3 kg/yr.