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
Captive killer whales they are successful, and withholding it when they are not. Secondary reinforcement—things not essential to life, such as play time, tactile rewards and fun games—can also be used as rewards. The practice of keeping killer whales in captivity is controversial, and organizations such as World Animal Protection and the Whale and Dolphin Conservation campaign against the captivity of killer whales. Orcas in captivity may develop physical pathologies, such as the dorsal fin collapse seen in 80–90% of captive males. The captive environment bears little resemblance to their wild habitat, and the social groups that the killer whales are put into