Animal experts are baffled after a group of up to 2,000 dolphins were spotted off the coast of west Wales.
Marine biologists said it was "massively unusual" to see so many in this area, and they don't know why the group of sea creatures is there.
It's thought they could be there because there's lots of food sources in the water and not many predators.
One eyewitness said: "There were dolphins of all ages - and they were leaping out of the water."
Cliff Benson, who does marine survey work in the Pembrokeshire area, described the site of the dolphins as being like a "volcanic eruption."
"There were adults and mothers with their babies. It's a mystery as to why there were so many," he said.
"People think they have to go to Florida to see dolphins leaping out of the water, but it's all right here," he added.