Digestive system of humpback whales stretching like an accordion. They allow whales to open their mandible to 90 degrees to gulp water and prey. They expel saltwater through the baleen plates, leaving behind krill and plankton. The whale's tongue plays a vital role in filter feeding, as it is used to push the water out of its mouth while keeping the prey trapped in its baleen bristles. As humpback whales do not have teeth, their food is swallowed whole and travels down the esophagus into the preliminary stomach (known as the forestomach) to be ground. Baleen whales have a multi-chambered stomach, divided into three distinct
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