What did one dolphin say to the other dolphin?
We can't know for sure, but whatever the joke is, these beautiful creatures look to be sharing a big laugh.
They are playing one of their favourite games - blowing vast clouds of bubbles and then biting into the rings they make, so they burst into smaller bubbles which float to the surface more quickly.
Sometimes the dolphins even dive through them - just for fun.
Having a great ol' time: These bottlenose dolphins dance and blow air underwater for fun. From left to right, there's Achille, 4, Bonnie, 30, Ulisse, 9, Bravo, 28, Silver, Golia, Tabo, 13, Ulisse, Candy, 27
This incredible image of bottlenose dolphins was captured by photographer Leandro Stanzani at the Oltremare Aquarium in Riccione, north-east Italy.
A theme park dedicated to the Adriatic Sea, it boasts the world's largest dolphin facility - with a 9,000sqm lagoon, containing 9 million cubic metres of saltwater.
Its main attraction is its gigantic glass window, through which enthralled schoolchildren can learn about these intelligent animals.
Bottlenose dolphins are the most common of 45 different types of dolphin, and scientists at the aquarium have been studying how they use sound and echo location techniques.
It is these remarkable skills which allow them to play together in harmony.
They use sonar to determine the size and location of objects in the water - including prey - by emitting clicking noises and listening to the resulting echo.
And - unprompted by trainers - these animals certainly look to be enjoying themselves.
They range in age from four-year-old Achille (on the far left) to 30-year-old Bonnie (his mother, second on the left).
Dolphins have an average lifespan of 20 years, but have been known to live to 50 - which, considering all these underwater high jinks, is an awful lot of time to spend blowing bubbles.
Read more: http://www.dailymail.co.uk/news/article-1209343/Want-hear-dolphin-joke-The-playful-creatures-share-big-laugh-blow-bubbles.html#ixzz0PLDtTGLR