beaked whale is one of the most recently described members
of the genus, and appears to be the smallest of the
species of Mesoplodon. Two morphs exist, a scarred black
and white form that is easily identified in the field
(presumably adult males), and a smaller uniformly brown
one (probably females and subadults). These animals
have moderately long beaks, and low triangular dorsal
fins with slightly falcate or straight trailing edges.
They tend to be dark gray above and lighter below, apparently
with relatively little scarring. They have small, triangular,
wide-based dorsal fins that are shaped like those of
The most distinctive characteristic is the teeth;
however, which are extremely small and egg-shaped
in cross section (although generally they are not
visible in at-sea sightings).
This is the smallest known species of Mesoplodon;
maximum known length is only 3.9 m, apparently with
males larger than females. At birth, these animals
are about 1.6 m long.