Hector's dolphin is the smallest of the delphinids. Mature adults
have a total length of 1.2-1.6 m and weigh 40–60 kg. The species is
sexually dimorphic, with females being slightly longer and heavier
than males. The body shape is stocky, with no discernible beak. The
most distinctive feature is the rounded dorsal fin, with a convex
trailing edge and undercut rear margin. The overall appearance is
pale grey but closer inspection reveals a complex and elegant
combination of colours. The back and sides are predominantly light
grey, while the dorsal fin, flippers and flukes are black. The eyes
are surrounded by a black mask, which extends forward to the tip of
the rostrum and back to the base of the flipper. Source