Researchers at the University of Puerto Rico, School of Medicine have found a way to pharmacologically induce a memory of safety in the brain of rats. Administering brain-derived neurotrophic factor (BDNF) into the prefrontal cortex prevented rats from expressing fear to a tone that had been previously paired with a shock. Rats given BDNF acted as if they had received repeated presentations of the tone without the shock, a procedure called extinction.

While trying to understand a disease that is wiping out frogs worldwide, researchers discovered a new frog species.

For the first time, researchers at the Smithsonian Tropical Research Institute track unique signals from tiny transmitters glued to individual orchid bees, yielding new insight into the role of bees in tropical forest ecosystems.

Young giant sharks, now extinct, may have grown up in shallow water nurseries, according to new findings from Panama's Gatun Formation.

The fifth Howler Monkey census at the Smithsonian's Barro Colorado Island research station in Panama, organized by Katie Milton, University of California, Berkeley, revealed that monkey numbers have not changed significantly since the first census 33 years ago.

In the first barcoding survey of sand flies in Panama, scientists at the Smithsonian Tropical Research Institute and Gorgas Memorial Laboratories identified 20 sand fly species from Barro Colorado Island. Two species carried Leishmania naiffi, a parasite that causes cutaneous leishmaniasis. Three species carried Wolbachia, a bacterial parasite of insects that could contribute to a strategy to control the flies and limit disease transmission.

The discovery of a new fossil turtle species in Colombia's Cerrejón coal mine by researchers from the Smithsonian Tropical Research Institute in Panama and the Florida Museum of Natural History helps to explain the origin of one of the most biodiverse groups of turtles in South America.

Lions, tigers and bears top the ecological pyramid -- the diagram of the food chain that every school child knows. A new study examines complex interactions in the middle of the pyramid, where birds, bats and lizards consume insects. These predators indirectly benefit plants, Smithsonian scientists report.