horny plates which hang from the roof of the mouth in some whales (Mysticeti), e.g. right whales and rorquals. The plates filter out krill (small shrimplike crustaceans) from the sea water as it is forced out of the mouth.
On the basis of annual oscillations in radiocarbon content along baleen plates, Schell and Saupe (1993) estimated that the baleen grows more than 50 cm in the first year of life and then the growth rate slows markedly, e.
Travelling inside the whale's mouth, 3-D images show how teeth have formed huge baleen plates which act like sieves, filtering out 70 tons of water from the throat pouch, and how the whale's tongue brushes industrial quantities of krill down its throat.
The baleen plates (whalebone) that hang from the upper jaw, used by the whale to strain small crustaceans from mouthfuls of seawater, are longer in the bowhead than in any other species, and were avidly sought by Euro-American whalers (Reeves and Leatherwood 1985).