Toothed whale whales do not have wax ester deposits nor branched fatty chain acids in their blubber. Thus, more recent evolution of these complex blubber traits occurred after baleen whales and toothed whales split, and only in the toothed whale lineage. Toothed whales have torpedo-shaped bodies with inflexible necks, limbs modified into flippers, nonexistent external ear flaps, a large tail fin, and bulbous heads (with the exception of sperm whales). Their skulls have small eye orbits, long beaks (with the exception sperm whales), and eyes placed on the sides of their heads. Toothed whales range in size from the and vaquita to
Channel types Channel types A wide variety of river and stream channel types exist in limnology, the study of inland waters. All these can be divided into two groups by using the water-flow gradient as either "low gradient channels" for streams or rivers with less than two percent (2%) flow gradient, or "high gradient channels" for those with greater than a 2% gradient. Low gradient channels of rivers and streams can be divided into braided rivers, wandering rivers, single thread sinuous rivers (meandering), and anastomosing rivers. The channel type developed depends on stream gradient, riparian vegetation and sediment supply. Braided rivers tend