A beloved 43-kilogram tortoise has gone missing from an environmental centre in New York.

The tortoise’s disappearance became known on Monday, when workers at the Alley Pond Environmental Center found only one of two tortoises in the holding area for a guest viewing.

“We aren’t sure what happened, detectives are still looking into it," Sasha Sicard, a member of staff at the centre, told CTV News Channel.

“There were signs of breaking and entering, our gate was damaged, there were footprints in our backyard."

While the intention behind a possible theft is not clear, Sicard said the tortoise, named Millennium, could be considered a delicacy by some; this, coupled with Millennium’s lofty price tag, has left the animal’s caretakers concerned for its well-being.

"We want to stay hopeful and say that maybe he got a good home, but we don’t know for certain,” Sicard said.

“It could just be someone wanted to sell him to make some money off of him, they do cost a lot. They are expensive pets.”

Millennium is believed to be anywhere between 17 and 100 years old.

"Our veterinarian says he's 17, but we've had him for 12 years and he's been full-grown since then, and these tortoises reach full-grown at 15,” Sicard told CTVNews.ca.

“Some of our employees say he could be up to 100 [years old], so there's some uncertainty there."

The reptile is believed to have been taken between the evening hours on Sunday and early Monday morning, Sicard said.

Below is an Instagram post shared by the Alley Pond Environmental Center back in May, with Millennium the tortoise on the left