Zoo keepers at Perth Zoo are concerned that an endangered tortoise missing since Tuesday could have been stolen and sold off in the black market. According to the zoo authorities, the 10-year-old tortoise was gone on Monday evening. The police are currently searching for it and the thief.

The zoo keepers noticed it was missing from its enclosure when they arrived on Tuesday morning. The creature is highly sought after by wildlife traffickers for its unique star-shaped shell. The staff expressed concerns that it could be stolen to be sold on the black market and said they are worried about its welfare at it fed on special diet and needed to be kept at a certain temperature to be able to digest the food.

“This is an extremely rare tortoise and in danger of extinction,” the ABC quoted Perth Zoo director of life sciences Maria Finnigan as saying.

She added, “The reason for the theft is unknown, however due to their stunning shells, radiated tortoises are heavily impacted by the illegal wildlife trade and regularly trafficked and sold on the black market. We hold grave concerns for the tortoise. This species have a specialised diet and like all tortoises it needs help thermo-regulating which is especially important at the moment as we are experiencing cooler mornings.”

Found in the island of Madagascar, radiated tortoises as they are known as, have become rare due to loss of habitat and poaching. The tortoise stolen from the zoo is a sub-adult and is about 15 centimetre in diameter.

However, according to Finnigan, there was no sign of a break-in.

“You would have to know how to enter into that exhibit, and you would have to know how that alarm system operated in that exhibit,” Finnigan said. “But again it’s just speculation because it really does need to be looked at carefully.”

The zoo has appealed to anyone who might have information on its whereabouts to contact them or the police.

The BBC reported that it is not the first time a radiated tortoise was stolen from the zoo. In 2011, two radiated tortoises were stolen from the same enclosure.