Eleven Aldabra giant tortoises hatch on Cousin Island as Seychelles researchers try to learn why wild nests fail

Eleven Aldabra giant tortoise hatchlings have emerged in a controlled hatchery on Cousin Island in the Seychelles, Nature Seychelles said on 6 November. They came from a nest of 16 eggs, the first collected this year, and hatched over the weekend of 31 October to 1 November. Two or three more were expected to follow. The young tortoises are being cared for at the island's field center.

Why so few wild nests succeed

The hatchery is part of a study into what affects egg development and hatching success. Over the past few years, Nature Seychelles has monitored more than 15 wild giant tortoise nests on Cousin Island Special Reserve, and only one hatched successfully. Working with scientist Alessia Lavigne, the team found that some eggs were fertilized and began to develop, but stopped before hatching.

Testing what eggs need

Three nests are part of the current investigation, and two have failed so far. In the latest trial, eggs were placed at a shallower depth in the sand. Nature Seychelles describes the work as continuing research and has not named a cause for the failed nests. An earlier controlled hatching was held for longer because of drought, the organization said.

Chris Tagg, science officer at the special reserve, collects the nests and guides the volunteers who help. The organization did not say how many tortoises live on Cousin.

Released once their shells close

The hatchlings will join the island's free-roaming giant tortoises, but not yet: their shells first need time to close completely. No release date was given. More stories like this are collected under wildlife conservation.