A rare white alligator in a zoo in the US state of Nebraska went under the knife on Feb 15 to remove 70 coins that were found in its stomach.

The authorities at Henry Doorly Zoo and Aquarium in the city of Omaha believe visitors had thrown the coins into the 36-year-old Thibodaux’s enclosure, according to media reports.

The coins were found during a routine examination, CNN reported.

They were worth around US$7 (S$9), KSBW Action News reported on its website.

Following the discovery, the zoo workers acted quickly to remove the coins “before they caused any problems”, BBC reported.

The alligator was anaesthetised and intubated for the procedure, associate veterinarian Christina Ploog, who led the procedure, said in a statement.

“A plastic pipe was placed to protect his mouth and safely pass the tools used to access the coins, such as a camera that helped us guide the retrieval of these objects,” she said.

In a statement, the zoo said X-rays confirmed all the coins had been extracted.

Thibodaux has recovered from the procedure and is back in its habitat.

Ms Ploog said coins can contain dangerous chemicals, which could harm animals that ingest them.

She believes the coins were tossed into Thibodaux’s mouth because they are so thin and “to be able to get them off the ground would be very difficult”, KSBW quoted her as saying.

The zoo said guests should not throw coins into its enclosures because the animals might pick them up. The zoo said it has a wishing well where guests can safely offload their loose change.

The zoo has 10 American alligators, according to CNN.

Thibodaux is a rare leucistic alligator, which have translucent white skin and deep blue eyes, according to the Audubon Nature Institute.