Whale than males. Baleen whales have no teeth; instead they have plates of baleen, a fringe-like structure used to expel water while retaining the krill and plankton which they feed on. They use their throat pleats to expand the mouth to take in huge gulps of water. Balaenids have heads that can make up 40% of their body mass to take in water. Toothed whales, on the other hand, have conical teeth adapted to catching fish or squid. Baleen whales have a well developed sense of "smell", whereas toothed whales have well-developed hearing − their hearing, that is adapted for both
Whale conservation certain other species of high intelligence: humans, other great apes, bottlenose dolphins and elephants. There is an argument that whales should not be killed because of their high intelligence. Pro-whalers claim that pigs also possess high intelligence, and are routinely butchered and eaten, and that intelligence should not be the determining factor of whether an animal is acceptable to eat or not. Whale meat products from certain species have been shown to contain pollutants such as PCBs, mercury, and dioxins. Levels of pollutants in toothed-whale products are significantly higher than those of baleen whales, reflecting the fact that toothed whales