Eight tortoises are used to stepping on the scales for a fortnightly weigh-in.
Every two weeks Ungulates Keepers weigh six African spurred tortoises and two Hermann’s tortoises to make sure they are healthy.
Ungulates Section Leader, Jay Haywood, said: We weigh them to see if there is any variation in their weight which helps us to monitor their health.
If they ever become ill it is very difficult to tell by just looking at them if they have lost weight, so we put them on the scales every fortnight.
The African spurred tortoises are so similar in appearance staff struggled to tell them apart so marked them with a variety of colours which has made it easier to identify the animals for weighing.
Jay added: Its so much easier to check their growth now we have colour coded their shells with a dab of paint.
African spurred tortoises originate in the deserts of Africa and can grow to three feet in length.
They are also known as Sulcata Tortoises (Sulcata means furrowed and refers to the ridges on their scales).
Tortoises are an endangered species due to demand for fashion accessories and ornaments made from their shells.
Take a look at our short video below to see Keeper Adam Davey explain the importance of the tortoise weigh-ins.