It's not an unusual site to see pods of dolphins in Cornish waters, but recently an unexpected guest has been joining in on one of the pod's fun. 

In the past ten days, there have been two separate sightings of bottlenose dolphins swimming and interacting with a lone harbour porpoise, who seems to have joined up with their pod.

While not exactly sworn enemies, bottlenose dolphins often aggressively attack their smaller harbour porpoise cousins, often playing with them like a football, launching them into the air and eventually killing them.

Falmouth Packet: Having a great time! Having a great time! (Image: Supplied)

However, in this case, the small porpoise and the larger dolphins seem to have teamed up, enjoying acrobatic games and swimming between Newquay and St Ives. The porpoise was even copying the dolphin’s familiar forward leaps, which is very unusual.

Terry Carne is a longstanding ORCA OceanWatcher and marine mammal surveyor. He was conducting his daily ORCA OceanWatchers survey from shore when he witnessed this very rare pairing in Newquay earlier this month.

READ MORE: Multiple pods of dolphins spotted off beach in Cornwall

Terry said: “I saw two bottlenose dolphins coming in towards land, which were the first I’d seen at Newquay for a long time. As they got a little nearer, I thought there was a third, all breaching, but realised that one was in fact a porpoise.

“I assumed that the porpoise was trying to escape, and when I saw it leap in the air I thought the bottlenose had struck it. But actually, what I saw was the porpoise breaching with the dolphins, initially forward leaps, before seeing it jump high in the air.”

Just six days later, the same dolphins were spotted near St Ives, again with their smaller porpoise buddy tagging along.

Falmouth Packet: Harbour porpoise wins the leaping out of water competitionHarbour porpoise wins the leaping out of water competition (Image: Supplied)

Lucy Babey, head of science and conservation at ORCA said: “The pairing up of these two different species is highly unusual. While they share the same habitat, porpoises tend to steer clear of dolphins, so to see them playing and sticking together over such a long period is a rare event.”

“We recently learned about an orca named Sædís in west Iceland that had seemingly adopted a new-born long-finned pilot whale, even though orcas and pilot whales also chase and antagonise each other.

READ MORE: Video of whale in Carbis Bay, Cornwall by fisherman James Tanner

"There has been a lot of speculation around whether this was aggressive adoption or if the calf had been abandoned, but it does show the empathy that animals have for different species”.

ORCA is appealing to marine wildlife enthusiasts in Cornwall to download its OceanWatchers app and to look out for the trio and see if they are still staying together.

The ORCA OceanWatchers programme is designed so that everyone can collect data about whales and dolphins in a flexible way, enabling even more people to become an integral part of ORCA’s conservation work.