Tropical frogs that can lay their eggs either in or out of the water may have an advantage as rainfall patterns change.

Almost half of the tropical forest reserves in a new study are ineffective, according to results published in the journal Nature by William Laurance, research associate at the Smithsonian Tropical Research Institute now at James Cook University in Australia and more than 200 co-authors.

Big seeds produced by many tropical trees were probably once ingested and then defecated whole by huge mammals called gomphotheres that dispersed the seeds over large distances. But gomphotheres were probably hunted to extinction more than 10,000 years ago. So why aren't large-seeded plants also extinct? A new report suggests that rodents may have taken over the seed dispersal role of gomphotheres.

Even the world's largest snake, Titanoboa, could probably not have swallowed this new, very round fossil turtle species from Colombia.

Population estimates for the Amazon basin just before Europeans arrived range from 2 to 10 million people. A new reconstruction of Amazonian prehistory by Smithsonian scientist Dolores R. Piperno and colleagues suggests that large areas of western Amazonia were sparsely inhabited. This clashes with the belief that most of Amazonia, including forests far removed from major rivers, was heavily occupied and modified. See this publication in the June 15 issue of Science.