What did the dolphin say to the porpoise?
A dolphin in Scotland's Firth of Clyde may be exchanging messages with porpoises.
The dolphin, named Kylie, usually makes clicking sounds with a frequency of around 100KHz.
But after interacting with a group of local porpoises he changed his tune.
Research from the University of Strathclyde found that Kylie's clicking became higher than normal, and closer to that of his new found friends, who generally make sounds at 130KHz.
He has made his home around a navigational buoy between Fairlie and the Isle of Cumbrae, in western Scotland.
University of Strathclyde PhD student Mel Cosentino has been analysing the sounds.
"We have some more recording to do with Kylie when he is on his own and when he is with the group of porpoises," she said.
"We want to see whether he is imitating the porpoises, like when we bark back at a dog or there is something else going on."
Ms Cosentino should know soon whether Kylie really is communicating or merely imitating.
She said that if further analysis showed the latter to be the case, it would be the first time a common dolphin has demonstrated an ability for "production learning" - where it has learned to imitate another species.
Follow Pallab on Twitter