A study was made of spontaneous renal adenocarcinoma in Rana pipiens collected from natural populations. Previous studies of prevalence have been made on purchased frogs and it is now well documented that renal tumor rate increases with storage. The present study provides tumor data on unstored R. pipiens taken directly from their native habitat. Collections of over 2,000 frogs were made in spr...

Renal adenocarcinomas of the leopard frog, Rana pipiens, collected in Kandiyohi County, Minn., were fixed for electron microscopy prior to and 4, 7, 13, and 16 days after the entry of host frogs into lakes for overwintering. Fifteen tumors were studied. No herpesviruses were detected in 4 tumors of prehibernating frogs. Two tumors of frogs autopsied on Day 4 of overwintering did not show viruse...

We compared physiological characteristics and responses to experimental freezing and thawing in winter and spring samples of the wood frog, Rana sylvatica, indigenous to Interior Alaska, USA. Whereas winter frogs can survive freezing at temperatures at least as low as −16C, the lower limit of tolerance for spring frogs was between −2.5C and −5C. Spring frogs had comparatively low levels of the ...

Background. Frogs are generalist predators of a wide range of typically small prey items. But descriptions of dietary items regularly include other anurans, such that frogs are considered to be among the most important of anuran predators. However, the only existing hypothesis for the inclusion of anurans in the diet of post-metamorphic frogs postulates that it happens more often in bigger frog...

We used simulations from a biophysical model that integrates interlinked exchanges of energy and water between frogs and their environments to address questions about the limits to thermoregulation and about adaptations for arboreality. Body size and cutaneous resistance (Rc) both significantly affected body temperature (Tb) and the time to desiccate to 70% of standard mass (an ecologically rel...

Introduction Since Cryptosporidium can be transmitted by ingestion of infected food animals and poorly treated water and by direct contact1 it is possible for infection to occur through ingestion of under cooked frogs and through handling and processing of infected frogs. In Burkina Faso frogs caught are sold to market-women who treat the frogs by emptying their bowels and frying in oil before ...

Frogs are an ancient group compared to placental mammals. Yet, although there are about as many species of frogs as there are of mammals, zoologists consider that frogs have undergone only limited morphological divergence, while placental mammals have diversified greatly in morphology and way of life. The serum albumins of numerous frog species were compared by the quantitative microcomplement ...

We have succeeded in creating see-through frogs from natural color mutants of the Japanese brown frog Rana japonica, which usually possesses an ochre or brown back; this coloration enables the organs, blood vessels, and eggs to be observed through the skin without performing dissection. We crossed two kinds of recessive color mutant (black-eyed and gray-eyed) frogs through artificial inseminati...

We conducted a long-term inventory of the herpetofauna Wildsumaco Wildlife Sanctuary in eastern part Napo Province Ecuador. This private preserve is about 500 ha size and located on southern slopes Volcán Sumaco. The contains primary forest, secondary pasture habitats. Based mostly nocturnal transect sampling we documented 39 species amphibians including one salamander, two caecilian...

The relationship between amphibian immune function and disease susceptibility is of primary concern given current worldwide declines linked to the pathogenic fungus Batrachochytrium dendrobatidis (Bd). We experimentally infected lowland leopard frogs (Lithobates yavapaiensis) with Bd to test the hypothesis that infection causes physiological stress and stimulates humoral and cell-mediated immun...