Baleen this issue. A whale's baleen plates play the most important role in its filter-feeding process. To feed, a baleen whale opens its mouth widely and scoops in dense shoals of prey (such as krill, copepods, small fish, and sometimes birds that happen to be near the shoals), together with large volumes of water. It then partly shuts its mouth and presses its tongue against its upper jaw, forcing the water to pass out sideways through the baleen, thus sieving out the prey, which it then swallows. People formerly used baleen (usually referred to as "whalebone") for making numerous items where
Mammalodon to archeocetes and the ancient toothed baleen whale "Aetiocetus", the breastbone is composed of several pieces. The top-most breastbone, the manubrium, is T-shaped and wider than is long like archaeocetes, but plate-like and compressed like modern baleen whales. Unlike in modern whales though similar to archaeocetes, the thyrohyoid bone of the hyoid apparatus used to hold up the tongue is large and tubular as opposed to plate-like. It proobably had a fused mandibular symphysis linking the two halves of the jaw together, unlike in later and modern baleen whales. As with the closely related genus "Janjucetus", "Mammalodon" lacked baleen, instead