10/02/2017 10:09 AM AEDT | Updated 10/02/2017 2:52 PM AEDT

Dolphins Might Be Chewing On Blowfish To Get High

This playful behaviour has caught the eye of scientists.

Krista Nicholson
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Dolphins are known to be the lovable, playful creatures of the sea. They've recently been observed off the Western Australian coast playing with some unusual toys -- blowfish. Krista Nicholson, a PhD student at Murdoch University, has seen this behaviour first hand.

"They're very playful creatures. We often see them play with any object they have like seagrass and we often see them play with crabs," Nicholson told The Huffington Post Australia.

"We've actually observed the animals tossing the blowfish out of the water."

Blowfish, or 'blowies', have a signature response to danger -- they suck water into their stomach and inflate when in trouble. They also release a toxin called tetrodotoxin which is present in the fish's skin and internal organs.

"There are some reports that the dolphins bite the fish to have the response, then play with it, then the fish deflate then they bite down again to inflate again," Nicholson said.

There are many theories as to why dolphins do this. One of them suggests the dolphins are getting a narcotic effect from the tetrodotoxin. Basically, they get a high from chewing on blowfish. The phenomenon was featured in a BBC documentary called 'Dolphins - Spy in the Pod'.

"That's one kind of theory, that is not a scientifically proven theory, that they are actually seeking a high. Nobody has actually proved that this is the case," Nicholson said.

"There are some views that the toxin wouldn't make them high, it would make them numb."

However, similar behaviours have been observed in other animals. According to Nicholson, some birds are known to eat fermented berries and elephants consume fermented fruit to get drunk, while wallabies have been seen eating poppies to get high.

There is a serious side to Nicholson's observations. The aim of the Mandurah Dolphin Research Project, which began in January 2016, is to track groups of dolphins in the Peel-Harvey waterways, just off the coast south of Perth.

Researchers are conducting a stock assessment of the bottlenose dolphins and observing if they cross between state and federal waters. The state and federal governments will then be better informed when managing this beautiful species.

The main threat the dolphins face is from pollution and entanglement in fishing lines.

"It's very serious and causes painful death," Nicholson said.

"We're calling for responsible disposal of fishing lines."