Risso’s Dolphin (Grampus griseus), family Delphinidae, found worldwide in cold to temperate waters, but mostly found along continental shelves

Risso's Dolphin Grampus griseus

It is found in oceans worldwide. These dolphins grow to be about 10 ft in length and can be identified by heavy scarring that appears white. Scars may act as an indicator of male ‘quality’ during aggressive social interactions. They feed almost exclusively on squid.

Very cool find from last spring- a Florida vinegaroon (Mastigoproctus floridanus) that was hiding inside a rotting log.

despite her impressive size, this rarely encountered Florida endemic is actually the smallest of the 3 vinegaroons in the US, and some of the Mastigoproctus species from Mexico and southwards get even larger.

and yes they’re called vinegaroons (among other fun names) because they squirt concentrated vinegar from their butt as a chemical defense

A Risso's dolphin (Grampus griseus) breaches in Monterey Bay National Marine Sanctuary, California, USA

Gramps

Work continues on the SECAC commission, and the end is in sight with just 2 more illustrations to go! I've just finished grandpa Grampus. Because after the "standard" Risso's dolphin (below, finished in 2022) SECAC also wanted an old male.

Risso's are very interesting in terms of colouration because they change so much throughout their life. They are born rather dark, and bear a colouration pattern akin to many other dolphins, with light grey undersides and a dark cape. Like pilot whales they have a white "anchor" marking on their chest, connected to a white patch on the belly. But as they age this colouration is snowed under by countless rake marks: scars brought on by the teeth of conspecifics. In many dolphin species these scratches quickly regain the same colour as the skin. In Risso's they stay white, likely acting as a sort of score bord for males to broadcast their fitness and fighting prowess.