U.S. News has named a member of the Ivy League as the best national university in each of the past fifteen years ending with the 2015 rankings: Princeton eight times, Harvard twice and the two schools tied for first five times.
Frogs tend to be nocturnal because night is the best time for them to catch prey such as insects and worms. Nocturnal terrestrial frogs are often brown or gray with spotted backs, while nocturnal tree frogs are usually green. These camouflage colors keep them hidden from predators as they sleep during the day.
1 Among the best known of rainforest amphibians are the tiny, but brilliantly colored poison dart (arrow) frogs [members of the Dendrobatidae family].2  These striking but slow-moving frogs secrete powerful toxins from glands on their backs and use their color to advertise their toxic composition to potential predators. Among the best known of rainforest amphibians are the tiny, but brilliantly colored poison dart (arrow) frogs [members of the Dendrobatidae family].