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.
Most frogs and toads are nocturnal, however there are some groups which are largely diurnal. These include the Dendrobatidae (poison-dart frogs) and Mantellas which are found in tropical forests of Central/South America and Madagascar, respectively. * The term diurnal refers to a tide which has a period or cycle of approximately one tidal day (about 25 hours). Diurnal tides usually have one high and one low tide each day. The tides at Karumba are a typical example of diurnal tides.