Captive tuatara are due to be weighed and measured before their winter hibernation.
The first reptile to go on the scales for the twice-yearly weigh-in will be at Natureland Zoo in Nelson.
Operations manager Gail Sutton says tuatara are in peak condition before they slow down for winter.
The information is collated and distributed to other wildlife centres with tuatara, which use it to ensure they are properly cared for.
