A large aggregation of sperm whales (Physeter macrocephalus) engaged in social activity. Note the abundance of sloughed off skin in the water, resulting from tactile contact among the whales. Peeling skin is apparent on the individuals in the center of this image. Note also the cloud of defecation. These whales had just emerged from milling around in a gigantic cluster, with many of the whales defecating to such an extent that the water was opaque.