Our two Saki monkeys are watching their weight after half-term treats led to a gain in grammes.
Now the cheeky small primates are hitting the weighing scales once a month as part of their regular health checks.
The weigh-ins enable keepers to spot evidence of monkey tricks at mealtimes when Deju and Rio receive their daily rations.
Trainee keeper, Cerys Grove – pictured with Deju and Rio explained: Because they have thick, hairy coats, its difficult to see whether one of them is hogging the food and getting fat, or maybe not eating enough and losing weight.
It was normal practice to weigh them once a month, but weve now trained them to hop onto the scales in return for a tiny piece of carrot or banana.
We have to vary the type of food to keep them interested and co-operative but the ploy seems to be working well.