Authors: R. A. Griffiths

Authors: Trevor J. C. Beebee

Authors: James W. Petranka

Authors: John Davenport And Thomas Dellinger

Authors: Peter Daszak

Authors: Harry V. Andrews

Abstract: In captivity, Varanus salvator attains sexual maturity when they are just over one metre in total length and 50 cm snout-vent length. Maturity can be attained at the end of two years. Males and females tend to grow throughout the breeding season. Egg-laying seasons are closely synchronized with those in the wild. No significant difference was noticed in clutch and egg sizes of younger females when compared to those of older and larger females.

Authors: Javier Martin-v Allejo, Javier Garcia-ferna Dez, Valentin Perez-mellado & Jose Luis Vicente-villardon

Abstract: We studied habitat selection, field body temperatures (TB) and activity cycles in sympatric populations of the lacertid lizards Podarcis muralis and Podarcis hispanica in a mountain area in Central Spain. Different patterns of habitat selection for the two species were found: P. muralis occupies N and NW facing talus sites, while P. hispanica shows a less habitat-specific distribution at the study site. Inter- and intraspecific differences in TBs were found, while thermoregulatory precision analyses showed differences between adult male and female P. muralis. Hypotheses based on activity cycles, habitat selection and basking behaviour are discussed to explain such results in two closely related species.

Authors: A. S. Cooke And R. S. Oldham

Abstract: The establishment of large populations of common frogs Rana temporaria and common toads Bufo bufo was monitored for six years in a newly-created reserve, following stocking with spawn of both species and with toads rescued from a site to be destroyed. Frog spawn output reached a peak three years after the initial introduction. There was high mortality and/or emigration (64% loss) during the first year following translocation of over 5,000 adult male toads. Thereafter male mortality decreased and/or site fidelity increased: 39% loss year 2 to 3, 42% loss year 3 to 4. Comparable data were not available for the 795 females translocated, but there is no reason to believe their mortality was lower. Transfer of spawn is probably more effective as a means of establishing a new population of toads than transfer of adults. Counts of male toads peaked after three years, but delayed sexual maturity of females meant that counts of pairs and estimates of spawn output continued to increase for about six years. Age determination in a sample of 4] male toads showed that length was significantly related to age, but there were some notably disparate rates of growth. A sample of 16 females showed no correlation between age and length. The greatest recorded losses of naturally-laid spawn of both species (up to 1 6% in one year for the frog and 39% for the toad) were due to desiccation, presumed collection by people and fungal infestation.