A group of an estimated 100,000 dolphins were video taped off the coast of San Diego, as they were traveling en masse.
"They were coming from all directions, you could see them from as far as the eye can see," Joe Dutra, who witnessed the event told NBC San Diego on Friday.
Dutra, who captains the Hornblower Cruises was at sea when the massive pod of Common Dolphins came by the boat.
Normally dolphins travel in groups of 15 to 200 and it is rare to see them in such a large group together, but Dutra was able to steer alongside the dolphins to give everyone on the boat a ring side seat to the action.
Dutra estimated that their were 100,000 dolphins in a group seven miles long and five miles wide.
Last year there was another group of dolphins that were seen swimming together about this time last year about 65 miles north of San Diego.
Marine mammal experts did know why there were so many dolphins together at one place, but theorized it may either be several schools together or there may have been plenty of food in the area.
"They're attracted to kind of the same thing, they might wind up in the same place," Sarah Wilkin, Marine Mammal expert told NBC San Diego.
Watch the video of the dolphin event by clicking on the video on the left.