Last Chance to See

by Mark Carwardine

  New Zealand’s wildlife evolved in complete isolation from the rest of the world (the nearest landmass is Australia, 2,000 kilometres/1,250 miles away across the Tasman Sea), so when people started to settle in New Zealand a thousand years ago it was ‘ecologically naïve’, to use the technical term. In other words, it was completely unprepared for the onslaught.

  The result was a swift and, in some cases, final one.

  Several dozen bird species have already become extinct. Among them were some of the weirdest and most astonishing birds ever to have lived on earth: the remarkable sexually dimorphic huia, in which the male had a short, woodpecker-like beak while the female had a long, downward-curving curlew-like beak; Haast’s eagle, which was the largest eagle ever to have lived, with a wingspan of 3 metres (10 feet) and talons as big as a tiger’s; and lots of different moas, giant ostrich-like birds with beaks like secateurs and eggs almost as big as rugby balls.

  The fastest extinction in New Zealand – possibly in the entire world – was the Stephen’s Island wren, which lived on tiny Stephen’s Island, in Cook Strait. It was discovered in 1894, when a new lighthouse keeper arrived on the island for the first time. One of his cats caught a bird he didn’t recognise, so he sent the little body to a friend in Wellington, who happened to be a professional ornithologist. By the time the excited friend sent news back that it was a species new to science, the cat had caught another fifteen. And that was it – there were none left.

  Stephen’s Island wren officially became extinct later the same year. The cat had eaten the first and last of the species, and all the others in between. Its owner, the lighthouse keeper, was the only person ever to have seen one alive.

  A tuatara millions of years old and a greying zoologist catching up.

  Nowadays, offshore islands like Stephen’s Island, and Codfish, offer the only real hope of saving the endangered wildlife that is left. Conservationists are transferring species that are in trouble on the mainland to these manageable safe havens. They are like bank vaults – places where kakapo and other valuables can be hidden away for safekeeping.

  Their isolation means that they can be cleared of predators and other aliens (like the grass seeds in Stephen’s socks or, more importantly, the ferrets, stoats, weasels, rats, cats, dogs, hedgehogs and possums that run amok on the mainland) and returned to the pristine state New Zealand once was.

  We began our kiwi adventure with one of the oldest animals in the world. It’s ancestral lineage dates back 200 million years, no less, which means that it was around pretty much throughout the Age of the Dinosaurs and has outlived all the dinosaurs by 65 million years… and counting. The tabloids would inevitably (though incorrectly) call it the ultimate ‘living fossil’.

  ‘But it’s just a lizard,’ said a rather disappointed Stephen, staring at the olive-green animal lying underneath a bush in Karori Wildlife Sanctuary, just outside Wellington.

  ‘Admittedly, it’s an out-of-the-ordinary lizard,’ he continued. ‘It’s got a bigger head than usual and sharp-looking spines along its back. It looks like something out of a Michael Crichton novel. But it’s still definitely a lizard. Isn’t it?’

  Actually, it was a 60-centimetre (2-foot) long tuatara. The spines along its back (which do look as if they were designed for Jurassic Park) give it its name: ‘tuatara’ is a Maori word meaning ‘peaks on the back’.

  But tuataras aren’t lizards for all sorts of reasons.

  The best one is that their razor-sharp teeth aren’t really teeth as we know them – they are little more than serrations of the jaw.

  Another is that the male tuatara doesn’t have a penis. No reptile has a penis, to be fair, but most have what’s called an intromittent organ that does the job pretty well. Many have two. But the male tuatara is seriously lacking in that department. This isn’t why the species is rare – although that would be a logical conclusion – because he mates with the female by squirting sperm from his cloaca into hers (a cloaca is basically an all-purpose hole for peeing, pooing and mating). People who are into this kind of thing call it a ‘cloacal kiss’. Yuk.

  Tuatara also have a remarkable third eye, on the top of the head. They’re not the only animals to have one of these, but it’s more pronounced in the tuatara than in most others. You can actually see it in the youngsters, but after about six months it gets covered by opaque scales and largely disappears.

  Scientists are still bickering about the function of the third eye. It has its own rudimentary lens, cornea and retina, suggesting that it evolved from a normal eye, but they’re all agreed that it wouldn’t be much good for seeing. It seems to be associated with the pineal gland – an amazing gland in the brain that produces melatonin to regulate what’s called the circadian rhythm. In other words, it probably helps to modulate wake/sleep patterns. It may also have something to do with hormone production for thermoregulation. Or it might help to absorb ultraviolet rays for the manufacture of vitamin D.

  Then again, for all we know, it might be an early electromagnetic tuner for picking up local radio.

  There are two different species of tuatara: Brother’s Island tuatara, which is by far the rarest, with about 400 survivors; and the common tuatara, with about 55,000. They were once found throughout New Zealand, but couldn’t cope with all the rats, stoats and weasels that made short work of their eggs and hatchlings. Some did make it to adulthood but they were caught by humans and sent overseas, where they were highly prized by collectors.

  It’s a wonder any survived at all.

  They became extinct on the mainland some time in the late 1700s, but small populations teetered on the brink in the relative safety of a few predator-free offshore islands. They became the first animals ever to be protected in New Zealand, in 1895, and have been a conservation priority ever since.

  The best news is that, thanks to Karori Sanctuary, a few dozen tuatara have just been returned to the mainland for the first time in centuries.

  Karori is just under three square kilometres (a square mile) in size and completely predator-free – an ecological oasis where native wildlife can roam without having to worry about aliens. Managed like a high-security prison (except the bad guys are on the outside), it is so secure that even house mice can’t break in.

  As the sun rose higher, our tuatara moved out from underneath its bush. Tuataras are cold-blooded, which means they spend a lot of time sunbathing to warm their bodies up to a suitable operating temperature.

  It was fully alert yet meditative, in an ‘I’ve got all the time in the world’ kind of way. It embodied a geological patience that was somehow fitting for a species that hasn’t physically changed in millions of years.

  ‘I like tuataras,’ said Stephen after a while. ‘They spend a lot of time sitting and staring. That’s what I’d like to do.’

  ‘You’d be bored in five minutes,’ I said. ‘Actually, make that one minute.’

  ‘Maybe. But life in the slow lane does appeal sometimes.’

  ‘I know what you mean. There’s a theory that it makes you live longer, too. The tuatara does everything slowly and lives for ages.’

  A rare glimpse into a nest of tuatara eggs.

  ‘It doesn’t seem to be breathing,’ said Stephen, suddenly concerned for its wellbeing.

  ‘That’s because it isn’t – well, not very often anyway. It could get away with breathing about once an hour, if it really fancied a lazy day. And being lazy does have advantages, because this tuatara is likely to outlive all its human protectors. It could easily live long enough to get a telegram from the Queen.’

  ‘Doesn’t she send emails these days? Or text messages from her iPhone?’

  ‘Does she have an iPhone?’ I asked.

  ‘I think President Obama gave her one. But I doubt if she’ll know how to use it. And I doubt very much if sitting and staring really makes you live any longer. Anyway, it would be a waste of time trying. Just imagine if you did sit around and stare a lot, and then died young, it would hav
e been a complete waste of time. It would be a bit like going to church, just in case there is a God and a faint chance of making it into Heaven, and then discovering that it was all a load of baloney. You could have spent your Sunday mornings doing something more productive.’

  ‘Like sitting and staring, perhaps? Even so, I think there is at least a grain of truth in the theory. Animals with low metabolic rates do tend to live longer than those with high ones. Shrews rush around in a complete panic, for instance, like traders on the floor of the Stock Exchange, and they live for a year or two at most; yet dormice spend much of their time fast asleep, or pottering about like retired librarians on an allotment, and they live for five years or more.’

  ‘Oh dear.’

  ‘Why “oh dear’’?’

  ‘Well, it makes you think, doesn’t it?’

  Stephen was still pondering the possible repercussions of his frenetic lifestyle when we noticed a slight movement on a rotting log right in front of us. It was another tuatara, so well camouflaged that we hadn’t seen it watching us intently from no more than 3 metres (10 feet) away.

  We felt quite shocked. Realising that you are being watched can be a little unnerving.

  I remember standing perfectly still in the Amazon jungle earlier in the year, looking around and yet seeing very little. I stood there and imagined all the countless animals of all shapes and sizes that were inevitably watching my every move. It sent a shiver down my spine. I told Stephen what I was thinking and he admitted that he’d felt exactly the same; neither of us mentioned it at the time.

  We were met in Karori by Professor Charles Daugherty, from Victoria University, and Sue Keall, who were keen to show us some tuatara eggs. These weren’t just any old eggs – they were the first tuatara eggs to have been laid in the wild on mainland New Zealand for over two hundred years.

  Charles and Sue took us to a little pink ribbon by the side of a path, and Sue started to pick away at the ground with her bare hands, like a palaeontologist on a delicate dig. After about ten minutes she stopped digging and beckoned us to have a closer look. We crouched down and looked into a short tunnel that led to an underground chamber: there, for all to see, was a clutch of small, extremely rare white eggs.

  ‘Can we touch them?’ asked Stephen.

  Sue laughed, but gave us permission, and gently we felt the tough, leathery shells.

  Female tuatara lay as many as fifteen eggs once every four or five years – not very often – then cover them with soil and wander off to sit and stare. That’s her job done (presumably because looking after eggs and hatchlings would mean lots of rushing about and that could shave years off her life).

  Charles explained how the temperature of the nest determines the sex of the young tuatara, as it does in many reptiles. If it is warm (22°C or above) they will be male, and if it is cool (21°C or below) they will be female. Who knows what happens if it is between 21°C and 22°C?

  Stephen liked this idea immensely and, while the rest of us listened in silence, he waxed lyrical about the likely impact of global warming on the natural sex ratio of tuatara, something about how varying temperature might work if there were three sexes instead of just two, and how different the world would be if the same thing happened in humans.

  ‘Does the pink ribbon mean they are all going to be girls?’ he asked excitedly, barely skipping a beat.

  ‘No,’ replied Sue. ‘It doesn’t. It’s just a pink ribbon.’

  There are many things to do in Wellington (or ‘the city they named after a boot’ as Stephen called it): a ride on the funicular railway, for example, or a visit to Te Papa Tongarewa Museum.

  The giant weta is so mild-mannered that holding one is much like holding the lead of an ageing labrador after a heavy meal. Note the tiny blue disc on this one’s back – a marker for research purposes.

  Surprisingly few people go to Matiu-Somes Island, an old quarantine station and internment camp in northern Wellington Harbour, specifically to see an oversized insect that looks like a cross between a cockroach and a cricket.

  We did. It wouldn’t have been Stephen’s first choice for a day out, but he agreed to come.

  Matiu-Somes is now a scientific and historic reserve – a 25-hectare (62-acre) sanctuary free of rats, possums and all the other introduced mammalian predators that have ravaged most of New Zealand. And it’s home to an extraordinary animal called the giant weta, or Cook Strait giant weta to be strictly accurate, which is a scary-looking creepy-crawly about the size of a mouse.

  In the ecological scheme of things it actually performs a similar role to that carried out by mice and other rodents in less peculiar parts of the world.

  Stephen didn’t like the sound of it at all.

  ‘We could have gone to an art gallery or strolled along the harbourfront,’ he complained on the twenty-minute ferry ride. ‘And you make us go to see an insect the size of a mouse. Good grief.’

  There are many different species of weta in New Zealand. Seventy, perhaps. Or maybe a hundred. To be honest, there just aren’t enough people studying them to know for sure. It’s a lot, anyway, and with their grasshopper-like bodies, long spiny legs and curved tusks, they are all instantly recognisable as such.

  The much-feared tree weta is the most famous, or infamous. A tough little animal, it is the pit-bull of the weta world. If it doesn’t like the look of you it hisses like a horribly large and dangerous venomous snake; and then, if it really doesn’t like the look of you, it will lash out with its spiky legs and give you an exceedingly painful bite.

  The Cook Strait giant weta, on the other hand, the one we were going to see, is the labrador of the weta world (it’s also the dinosaur of the insect world – but that’s another story). The ultimate gentle giant, it is a completely harmless and mild-mannered vegetarian. It rarely dislikes the look of anyone and is far too polite to show its feelings if it does. Like so many animals in New Zealand, it has lost the ability to fly. Sadly, it is so heavy that it has also lost the ability to jump. So all it can do is scuttle.

  We were met on the dock by rangers Jo Greenman and Matt Sidaway. Jo and Matt are among a grand total of three people living on Matiu-Somes (the other is Jo’s husband, who commutes to the mainland every day in a little boat).

  We hiked to the top of the island, admiring the views across the water towards the city skyline, and Jo introduced us to the concept of weta hotels. These are shallow wooden boxes placed on the forest floor to give wetas comfortable daytime hiding places (they rest during the day and come out at night).

  Carefully, we opened the lid of the nearest hotel and peered inside. There were four giant wetas in residence. They scuttled about in a complete panic, as if housekeeping had opened the door without knocking and caught them in the shower.

  Jo picked out the largest animal – one of the heaviest insects in the world – and gently placed it on the palm of my hand.

  ‘Don’t worry about that long thing,’ she said, reading my mind. ‘I know it looks like a stinger but it’s not. It’s a female and that’s her ovipositor – her egg-laying device. It won’t do you any harm. Though, in fact, the stings of bees and wasps are highly modified ovipositors, so it’s an easy mistake to make.’

  I held the giant weta in position (not all that difficult – much like holding the lead of an ageing labrador after a heavy meal) while Jo carefully glued a tiny blue disc onto its back. The disc had a number on it (96) and was part of a research project to learn more about giant weta movements and numbers.

  Stephen wanted to hold the weta, so I carefully prized its tiny hooked feet from my skin and handed it over.

  He gently tapped it on the back.

  ‘It’s got very tough armour-plating,’ he said.

  ‘That’s its exoskeleton,’ explained Jo. ‘We wear our skeletons on the inside and they wear theirs on the outside – which works pretty well until they need to grow bigger.’

  ‘So how do they do that?’

  ‘Well, when we grow bi
gger, we get bigger clothes. And that’s pretty much what a weta does – except it has to break out of its old jacket, its exoskeleton, and grow a new and bigger one.’

  Mark, overwhelmed with excitement over the latest mobile phone technology.

  Wetas are tough little animals. Rumour has it that one was held under water for four days and survived (but then rumour also had it that the incompetent chief executives of failed banks weren’t going to be allowed any more bonuses, so I’m not sure if this is true).

  ‘How many do you reckon there are on Matiu-Somes?’ I asked Jo.

  ‘We’re not sure – but if I had to guess I’d say around 15,000,’ she replied. ‘I know that sounds like a lot compared with a large animal like a kakapo, but it’s actually a very small number for a population of insects. We’re still worried about its future.’

  Stephen, overwhelmed with excitement after a day of weta-watching.

  Jo had a point – great numbers are no guarantee of survival, no matter what kind of animal you happen to be. A better measure is the level of threat.

  Take the North American passenger pigeon, which at one time was probably the commonest bird ever to have lived on earth. It is impossible to give an accurate estimate of the population at its peak, but conservative guesstimates suggest that it may have been as high as 10,000 million in the first half of the 19th century. It is likely that 35–45 per cent of all the birds in North America were passenger pigeons and they lived in huge, densely packed flocks which darkened the sky and could take up to three days to pass overhead.

  But colossal numbers were killed for their meat. Sports hunters took an even greater toll: hunting competitions were organised in which more than 30,000 dead birds were needed to claim a prize.

  The last passenger pigeon to be seen in the wild was shot by a young boy on 24 March 1900. On 1 September 1914 the last of all the passenger pigeons, affectionately known as Martha, died in captivity in Cincinnati Zoo, USA. They had been hunted to extinction in little more than a hundred years. Quite a lesson.