dolphin megapod california
Dolphin megapod filmed off California coastCraig Dewitt, Capt. Dave's Dolphin & Whale Safari

A mega pod of over 1,000 stampeding dolphins has been filmed off the coast of California during a whale watchers tour.

Dolphins normally travel in pods of about 200, but herds or super schools can gather in the several of thousands.

However, dolphin stampedes do not occur very often, and the "unusual behaviour" can happen without warning and without anything frightening the pod.

The mega pod was filmed during a tour with Captain Dave's Dolphin and Whale Safari.

Southern California has the greatest density of dolphins per square mile than anywhere else on earth, including 450,000 Common Dolphins.

Last year, Dave Anderson from the Dolphin and Whale Safari filmed a similar dolphin stampede using a drone launched from an inflatable boat.

Speaking at the time, he said: "This is the most beautiful and compelling five minute video I have ever put together. I learned so much about these whales and dolphins from this drone footage that it feels like I have entered a new dimension ... Drones are going to change how we view the animal world. Wow!"

In 2013, what could have been the biggest ever dolphin pod was seen from a cruise boat off the coast of San Diego.

The super-megapod is estimated to have had up to 100,000 dolphins and was five miles wide.

Joe Dutra, captain of Hornblower Cruises, told NBC San Diego: "When you see something like that it is truly beyond belief. They were coming from all directions. You could see them from as far as the eye can see.

"I've seen a lot of stuff out here but this is the biggest I've ever seen, ever. You had to be there to experience it. It was truly spectacular."