||Risso's dolphins, like this older pair near Massachusetts, USA, are often called "grampus".
Coloring is variable, but generally they are gray at birth, turn brown as immatures, and fade to light gray
as adults. Their dorsal fins usually remain dark, clear of the many scars most individuals acquire as they
age. Those distinctive scars may come from their squid prey, or perhaps tooth rakes made by other
Risso's, but other dolphin species have been seen to rake Risso's dolphins as well. While Risso's
dolphins may scar each other for social reasons, for example to establish dominance, why do other species
also do it? Sometimes groups forage spread out in a line, searching for prey near the surface. When one
dolphin in the line finds food will all the dolphins have a share, or do the dominant ones eat first?