St Helena’s most celebrated living resident has been found to be one of the last survivors of a species that was thought to have been killed off by hungry mariners. JOE HOLLINS, the island’s vet, describes how Jonathan the tortoise was found to be one of the lost Seychelles Giants.
Okay, I confess: I’ve been to prison: thick stone walls, a bunk bed, a grill on the door, and at dusk, a hurricane lamp to light the cell, delivered by a white-robed Arab. But before the governor signs a warrant to have me removed from St Helena, I should explain.
This was Prison Island. Through the bars of a deep coral window, across three miles of crystal blue sea, lay Stone Town, the seat of Arab slavery on the island of Zanzibar, just off the coast of Africa.
Prison Island is a scrap of coral just a few hundred yards long, cloaked in scrub and ringed with white sand and reefs. It was used by Arab slave traders to hold recalcitrant slaves, and no doubt render them obedient. Fortunately the single-storey prison was now a delightfully simple, lime-washed government hostel.
I had come to enjoy the island’s attractions: snorkeling, delicious fish dinners – and 100-or-so giant tortoises. Each morning they would come crashing out of the shrubbery to graze on the close-cropped irrigated lawn just outside the prison wall, living off very little and thriving remarkably. In fact, today their population stands at over 200.
The Aldabra Atoll, their original home and now a World Heritage Site, sits in a watery neighbourhood just a few hundred miles out in the Indian Ocean, part of the widely scattered Seychelles archipelago. Which means that Zanzibar and St Helena have something in common – they are both island homes to some remarkable chelonians (the posh word for tortoises).
There are just two races of giant tortoise in the world: the Pacific Ocean tortoise from the Galapagos – volcanic islands claimed by Ecuador – and the Indian Ocean tortoise from the islands of the Seychelles. The five St Helenian tortoises are all of Indian Ocean stock.
A number of separate giant tortoise species were said to exist in the area, but, alas, they proved the perfect takeaway for passing mariners: hardy, stackable, and stoutly packaged for easy stowage. Man blindly slaughtered them out of existence.
The island of Rodrigues alone had an indigenous population of 200,000, extinct within 100 years of dining afloat on roasted tortoise.
Fortunately the Aldabra Atoll was spared. It was far-flung, off the normal shipping routes, difficult to approach by sea – and had a very powerful friend. In 1874, Charles Darwin, seeing the inevitable extinction of all the world’s giant tortoises, petitioned the Governor of Mauritius, then administrator for Aldabra, to protect the atoll – and to good effect.
A recent census puts the population of the Aldabra Atoll at 100,000, which compared to the total Pacific population of 15,000 looks staggeringly healthy.
So the five St Helenian tortoises – Jonathan, David, Fredrika, Myrtle and Emma – seem at first glance to be relatively common. But now unfolds an extraordinary twist in the tale.
A few years ago the Seychelles Nature Protection Trust had an idea. If the tortoises are so long-lived – 150 years plus – then perhaps some of the eaten-out species weren’t quite so eaten-out after all, but alive and well in private collections.
Incredibly, a world-wide search uncovered two of the apparently extinct species, the Arnolds Giant and the Seychelles Giant. I contacted Dr Justin Gerlach of the Trust and he sent me a comparison chart: a list of different measurements to separate the species.
Passers-by would have seen me crawling beneath Jonathan and David, risking a bizarre and messy death, sizing up their scutes (the shell plates) on their plastrons (the under-shell) with a tape measure.
Result: David and the girls are certainly Aldabran Giants, but Jonathan’s measurements are quite different. He is a Seychelles Giant. Which makes him immensely rare – maybe one of a dozen left in the entire world.
Of course, life is never simple. Modern DNA testing has cast doubt on these old species classifications, but so what? At the very least Jonathan is a rare breed or subspecies, and of world significance.
He is also, by any estimate, creakingly old, and has probably exceeded his life expectancy. Sadly we can’t expect him to go on forever. Having said that, as the Governor will attest, he eats well and has a mighty fine libido, his efforts with the girls reverberating around the walls of Plantation. All joking aside, this means he is feeling pretty zesty.
On top of this, I also researched feeding, exchanging many emails with both the Seychelles and – thanks to Mike Thorpe – the curator of Bristol Zoo, who put me in touch with their specialist tortoise vet (yes, they really exist).
We looked at length of grass, type, access to water, and other foods. The principal fact to come out of this is that lush foods – fruit and vegetables – can, in any quantity, have disastrous, even fatal consequences.
In their natural habitat these tortoises graze on coarse scrub and grass, and wallow in mangrove swamps. Visitors will have seen that as well as the bath provided, the tortoises have recently created superb mud wallows, in one of which, dangerously overdeepened by rain, I had to do some mud wallowing myself to pack the base (risking another potentially bizarre and messy death).
We have also been playing with grass length. Initially we left the grass long across the width of Plantation paddock, but after several months it became clear that this simply acted as a barrier – no tracks penetrated it whatsoever.
However, the long grass on either side, peppered with shrubs and sheltered by trees, is much favoured, full of tracks and grazing zones and harbouring some of the wallows. These areas more closely imitate their natural habitat.
In addition, they spend much of their time grazing the shorter, lusher grass out in the open. It has to be remembered that back in the Seychelles, the sun-baked grass is sparse and wiry. It’s like comparing grapes with raisins.
So they do pretty well. Some concern has been expressed about the condition of one of the female’s shells, but I have sent detailed photographs to the tortoise vet, who laughingly told me that she was used to treating Madagascan tortoises caught in bush fires that looked like toasted almonds, and this was nothing to worry about. Indeed, some tortoises like to hang out under waterfalls and their shells grow mosses and lichens.
The shell, of course, is dead, like hoof and horn, and what the visitor sees is not the very serious condition called shell rot, as some have suggested, just flaky wear and tear. All the same we might do some aesthetic work, clean her up, and fill her worst holes with a special putty to stop them holding rain water.
What we will never do – another fallacy – is apply any polish or oil. This simply cakes the shell and encourages mould.
And the future? The combination of the soaring Georgian architecture of Plantation and the tortoises grazing on the lawn is an iconic image and a tremendous asset for tourism. Maybe we should start talking to the Seychelles about the next generation.