SULCATA GIANT TORTOISE HATCHLINGS

Cambridgeshires Wildlife Breeding Centre

THE MARCH OF THE GIANT TORTOISES

Tortoises have a special place in our hearts here at Linton Zoo, you will find many different species in our care, from beautiful little Starred to the mighty Aldabran Giants!

The African Spurred or Sulcata Giant Tortoises have always featured highly with us, our herd of six breeding adult’s average around 40 years old and they are all ex-pets. One has travelled the world with its former owner having been rescued as a hatchling from children using him as a football in Mauritania, Africa.

Each year our herd of African Sulcata Giant Tortoises produce a few young, but this year we’ve had a bumper hatch with 45 babies from two clutches. When a bit older these hatchlings will move to other parks and collections around Europe.
EGG LAYING
 

Around December/January the female tortoise will start to look for a suitable for a nest site, once found she will start to dig, around March time she will lay eggs in her nest. In the wild this is where the female will cover the eggs and leave them forever, she has no maternal instincts at all.

In England however the weather is not warm enough for long enough to allow for natural hatching so the eggs are removed for incubation.

 

The Sulcata is found from the West to the East coast of Central Africa and is currently ranked as Vulnerable by the IUCN Red List. Fortunately zoological collections have mastered the art of reproduction through captive breeding programmes and can supply Tortoises for re-release should this be necessary.

Their ability to live in a dry and hostile environment has to some extent saved the Sulcata. Man is still their biggest threat to survival, as habitat alteration and collection for food play a major role in their demise. They are also often used for target practice by some army training camps.
INCUBATION        

The eggs, which are the size of golf balls, are kept in the incubator at a constant 30°c. The temperature can determine how long the eggs take to incubate.

Our eggs were laid in March and April this year and began hatching in August with most hatching in September.

As with most reptiles the temperature the eggs are kept at during the 'thermosentitive period' of incubation can also determine the sex of the baby. At 28°c the hatchlings would predominantly be male, at 32°c they would be female. Keeping them at 30°c ensures we have a good selection of both males and females.

Sulcata's are the largest mainland species of Tortoise, a giant weighing up to 95kg and growing up to 90cm long. Tortoises are generally known for their longevity, being some of the longest lived creatures on the planet. There is no way to know the exact age of a tortoise unless you know its hatch date, but one record shows an individual living to 165 years old!
TORTOISE NURSERY
 

The young hatchlings are cared for in nursery tanks as it's far too cold for them to survive outdoors. In the wild the parents have nothing to do with the hatchling once the eggs are laid, so they are not missing out on any parental care.

In the wild hatchlings have quite a high mortality rate, being so small and having no-one to look after them they are picked off by all sorts of prey which may include, Hyenas, Lions, Alligators, Eagles and even other Giant Tortoises which see them as nothing more than a tasty meat pie!

The Sulcata giants have wonderful characters and are very entertaining as they are a very active tortoise, they can often be seen charging around their enclosure, surprising visitors with just how quick they can be. As hatchlings they are very appealing and many people take them on as pets without understanding just how large they will grow and how destructive they will be. They need a very strong enclosure with lots of space for them to graze and dig to keep them happy and safe.
FAMILY PORTRAIT
Aside from our cold climate if the hatchlings were left in with their parents there would be the risk of being crushed. Purely from their gigantic size the adults could quite easily, even if unintentionally, step or lay on a baby killing it.

But we thought it would be fun for you to see the size difference between hatchlings and their parents so we brought them into the adults paddock for a family portrait - under very close supervision of a team of 6 keepers.

Getting all 45 hatchlings to look at the camera at the same time however proved to be an impossible task!

Tortoises are quite pre-historic looking, first appearing around 220 million years ago marching straight past the dinosaurs to today. They have been, and still are, prized for their flesh; bone and shell by humans and many species face extinction due to over exploitation for food. Tortoise shell was widely used in the 1960s and 1970s in the manufacture of items such as combs, sunglasses, guitar picks and ornaments. In 1973, the trade of Tortoise Shell worldwide was banned under CITES (the Convention on International Trade in Endangered Species), since this ban a synthetic material has been produced to replicate the style.