A giant python has been folded in half and put in a scanner by Perth zookeepers, who are trying to find out why the 46-kilogram animal is off its food.

"Cuddles", a five-metre-long reticulated python, was transferred to Murdoch University Veterinary Hospital for a CT scan on Wednesday.

Reticulated pythons have a life expectancy of 25 years and Cuddles is estimated to have outlived that, with the zoo putting his age around 28.

Although it is not uncommon for snakes to eat less during cooler months, Perth Zoo felt that given the python's age, it was important to take a closer look.

Perth Zoo senior veterinarian Simone Vilati said standard tests used for most other animals were not always effective with big creatures like Cuddles.

"It's very difficult to do diagnostics on snakes of this size and strength, so we were looking for a means to get as much information as we could, as quickly as we could," she said.

"A full-body scan seemed to be the best way to go."

Zookeepers slipped Cuddles into a plastic tub on Wednesday, before driving him to Murdoch University, where hospital staff had prepared a special room.

"We asked them to get it up to an ambient of 28 degrees, which is not easy in a big room," Ms Vilati said.

"The anaesthetist spent a lot of time with a lot of heaters and heat lamps getting it up to that temperature for us.

"It's important to have reptiles warm when you anaesthetise them, so the drugs work properly.

"Because they're cold blooded, if you don't have them at a high ambient temperature, all their cellular processes shut down and the drugs don't work in a predictable way."

The procedure lasted for around an hour and a half, with zoo and hospital staff folding Cuddles in half in order to slide him through the $180,000 CT scanner.

Murdoch University's Dr Shona Reese said the logistics were challenging.

"It's not the first snake we've had through, but it's certainly the biggest," she said.

Cuddles recovered well from the procedure and has been moved back into his enclosure at Perth Zoo under the watchful eye of his keepers, who are awaiting the results of the scan.

Ms Vitali said she hoped there would be good news for Perth Zoo's only reticulated python.

"It'd be really nice if it was something minor," she said.

"If we find nothing on the CT scan, we'll be delighted."

Cuddles was originally dumped at Tooronga Zoo by illegal owners who staff believed had bitten off more than they could chew.