The melon gives these whales their characteristic rounded foreheads. To accommodate the melon, the skull is modified to form a pointed, dish-shaped face. The skull is also asymmetric, the right side being slightly different from the left side.
Belugas ( Fig. 9.28 ) have a bulging forehead, which changes shape as the melon, moved by muscles, focuses the sound. The
huge forehead of the sperm whale is fi lled in part with a massive melon called the spermaceti organ. Whalers originally
thought this was the sperm sac of the whale, hence the