Mesoplodon peruvianus Reyes, Mead & Van Waerebeek 1991

The pygmy beaked whale is the most recently described member of the genus, and appears to be the smallest of the species of Mesoplodon. They tend to be dark grey above and lighter below, apparently with little scarring. They have small, triangular, wide-based dorsal fins that are shaped like those of harbour porpoises. The most distinctive characteristic is the teeth, which are extremely small and egg-shaped in cross-section (although generally they are not visible in sightings at sea). Can be confused with: The small triangular dorsal fin is different from that of most other species of Mesoplodon, but using this character alone, it would be very difficult to dismiss the possibility of other species in sightings at sea.

This is the smallest known species of Mesoplodon; maximum known length is 3.7 m, apparently with males larger than females. At birth, these animals are about 1.6 m long.

Groups of 2 or 3 animals have been observed.The diet consists of small mid-water fishes, oceanic squid, and shrimps.

Pygmy beaked whales are taken in the driftnet fishery for sharks off the coast of Peru . IUCN: Insufficiently known.