Risso's Dolphin, or Grampus (Grampus griseus), photographed in Monterey Bay on 22 August 2014.
This is one of the largest dolphins in our area, often reaching a length of 10 feet. Note the distinctive coloration — pale gray, with abundant scratches and scarring (see below). The marks are probably from other dolphins, or possibly from their prey (such as squid).
The photo above also shows the tall, falcate-shaped dorsal fins.
Risso's Dolphins are most often observed offshore. However, they have been seen from Bodega Head, with a recent sighting just a few weeks ago. They primarily eat squid, so they might be following prey inshore.
Keep an eye out for Risso's Dolphins. If you see a larger group, they might display some interesting behaviors, including spyhopping (as in the photo below) or lobtailing.