Cetacea and two (external) limbs that are modified into flippers. Though not as flexible or agile as seals, cetaceans can swim very quickly, with the killer whale able to travel at in short bursts and the fin whale able to cruise at . Dolphins are able to make very tight turns while swimming at high speeds. The hindlimbs of cetaceans are internal, and are thought to be vestigial. Baleen whales have short hairs on their mouth, unlike the toothed whales. Cetaceans have well-developed senses—their eyesight and hearing are adapted for both air and water, and baleen whales have a tactile system
Double-toothed barbet the seeds of some fruits. These barbets can be found in pairs or small family groups with helpers; lone double-toothed barbets are rare. Their territories are large. Double-toothed barbets roost communally, as all the barbets in a group roost in the same hole. Nests are made by excavating a tree, often rotting, at above two meters. Both barbets in a pair will dig out the nesting hole, and both will defend it. The entrance the nest is circular, five or more centimeters across. Some nests have an entrance tunnel. At maximum, a nest is 46 centimeters deep. When a male