Catching rays
How hard could it be to find a manta ray? They’re six metres wide, after all.
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Why can’t I taste with my feet?
Fish taste with their fins. Butterflies taste with their legs. Octopuses taste with everything. Cats can’t taste sugar. So, why do humans taste only with their tongues, when there are taste receptors all over the human body?
Speedway
Andy MacDonald documents Nelson-based speedway driver Morgan Dumelow.
Gone to the dogs
When humans first reached New Zealand shores, sometime around the late 13th century, they were accompanied by two mammals: kiore (Pacific rats) and kurī (Polynesian dogs). This arrival triggered huge changes to New Zealand’s biodiversity: the extinction of moa, adzebills and Haast’s eagles, among others. Humans and rats usually get the blame—humans because of hunting and fire, rats because of their propensity to eat eggs, chicks and small animals. But what about kurī, the canine companion of Polynesian settlers? Kurī had white fur, and resembled something between a border collie and a fox. Scientists have long assumed that their ecological impact was minimal, because kurī lived alongside humans. Two University of Otago scientists are challenging this dogma. Kurī probably did play a role in the vast ecological changes following Polynesian arrival, they say. “It’s always been a gaping hole when we look at the impacts of humans on island ecosystems, especially in New Zealand,” says palaeoecologist Nic Rawlence, who collaborated with archaeologist Karen Greig to investigate the effect kurī had. “We’ve always assumed it’s been humans and rats. But dogs would actually have a huge impact: they fill a niche as predators of medium-sized animals like kiwi, kākāpō, takahē and ducks.” Aside from hunting wildlife, kurī could have competed with other predators for food, disturbed breeding animals, or introduced new diseases. Rawlence and Greig point to the impact of wild and pet dogs today: packs of feral dogs killing kiwi in Northland, or dogs disturbing colonies of seabirds, forcing them to abandon their nests. Even if kurī stayed close to camp, and were well-fed taonga, “that doesn’t necessarily mean that they didn’t go wild and hunt and have an impact on wildlife”, says Rawlence. Through archaeological evidence, we know that wherever people were, kurī were, too—and people were everywhere. If kurī strayed from human company and went feral—a subject of ongoing debate—the impacts could’ve been even greater. This area of study hasn’t exactly made Rawlence popular, though. “There seems to be this blind spot in New Zealand around the impact humans’ best friend can have on wildlife,” he says. “As you say, ‘Dogs have a big impact’, people tend not to want to know.”
Rock stars
The previous issue of New Zealand Geographic featured a story about rock hounds—people who fossick in rivers looking for interesting specimens. Several readers wrote to say they would have liked to see more of the rocks up close. Photographer Andy Macdonald became a keen rock fossicker himself while working on the story, and made ‘portraits’ of some of his own finds. Clockwise, from top left: the cut section of a botryoidal pounamu which also contains the minerals diopside and serpentine; an orbicular poppy jasper, so named for its texture and colour; unpolished pounamu; grossular garnet; pakohe, or argillite; the blue-tinted pounamu found in the Nelson region. Got thoughts about one of our stories? letters@nzgeographic.co.nz
Trending
For the love of velvet worms
Jungle warfare
Strike a pose
Sunfish have pretty sweet moves, actually
At the mercy of the ice
Most ancient rocks
The unforgiving face
Nothing to sniff at
If names have power, what should we call ourselves?
Seven steps
Archive
Streetscapes
Since 1955, New Zealand has prioritised cars in the design of our cities and streets. But what does that mean for anyone who isn’t behind the wheel?
Life under ice
A colony of icefish (Neopagetopsis ionah) 60 million nests in size swathes the seafloor of Antarctica’s Weddell Sea, researchers have found in an unprecedented discovery. Previously, the largest known icefish colony consisted of 60 nests. The research team was collecting routine seafloor data using a towed camera, and recorded about four to five hours of fish nests. The city-sized colony, which stretches for 240 kilometres, likely plays an important role in the entire Weddell Sea ecosystem. Gravel-bottomed nests dot the seafloor. Nestled within each hollow, pale blue eggs are guarded by an icefish parent. In another unexpected Weddell Sea discovery, researchers from the British Antarctic Survey drilled through an ice shelf to find an oasis of life that has persisted for thousands of years. Located several kilometres from the open ocean, in an environment characterised by darkness, extreme cold and lack of food, the 77 different species recorded included tube-building worms and bryozoans—also known as moss animals and sea mats.
Jade Kake wants to reinvent how we live
Her idea: to revive the papa kāinga, the communal Māori village.
Hungry, hungry humpbacks
Baleen whales eat three times as much food as we previously thought they did, according to a nine-year-long study published in the journal Nature. This means whales poo a lot more, too, with important implications for ocean ecosystems. Researchers used data from 321 tagged whales from seven species—including blue, minke, fin, and humpback whales—swimming in the Atlantic, Pacific, and Southern oceans. The tags tracked the animals’ movements, allowing the scientists to identify telltale feeding patterns. They used drones to photograph 105 whales and determine their lengths, then calculated how much water each could take in with a single mouthful. And they raced out to whale-feeding sites in small boats equipped with echo-sounders to measure the size of the krill swarms the leviathans were eating. The three lines of evidence revealed just how much whales were devouring: an adult blue whale in the North Pacific consumed an estimated 16 tonnes of krill per day during its foraging season. Tonnes of food means tonnes of poo, and in the process, whales dump iron into the water, helping to seed phytoplankton blooms, which in turn allow krill to flourish—suggesting that before industrial whaling decimated their numbers, whales were as important for ecosystem productivity and carbon storage as the forests of entire continents.
Champion divers
Black-browed albatrosses dive deeper and longer for kai than previously thought. The were believed to be shallow surface divers, but new data shows they can dive up to 19 metres and for as long as 52 seconds. Equipping 28 black-browed albatrosses with GPS backpacks and mini leg-mounted depth loggers, researchers tracked the birds’ foraging trips off the coast of the Falkland Islands. More than 20 per cent of dives recorded surpassed the previous record (around six metres) while 50 per cent of birds reached depths of 10 metres. This finding means that longlines used in commercial fishing probably need to be set at even greater depths to avoid accidentally snaring albatrosses. The researchers observed that most deep dives were restricted to daylight hours, so setting longlines at night may also help avoid bycatch. Black-browed albatrosses are found across the Southern Ocean, including in New Zealand waters. They number in the millions, but population decline means they are classified as “near threatened”.
The island that blew up
When Hunga Tonga-Hunga Ha‘apai erupted in Tonga on January 15, sending a shockwave around the globe, it rewrote scientists’ understanding of volcanology and tsunamis.
What’s eating kākahi?
The evidence: piles of discarded freshwater mussel shells, or kākahi. The crime: eating threatened species. Who was responsible? Waikato University rodent biologist Bridgette Farnworth wondered if Norway rats were the perpetrators. Farnworth embarked on a scientific whodunit, deploying cameras along Orongo Stream in western Waikato. The waterway is home to two types of freshwater mussel, Echyridella menziesii and E. aucklandica, which are both threatened species. As piles of shells appeared sporadically along the banks of the stream, she shifted her cameras in hopes of catching the perpetrators in the act. She was capturing lots of footage of Norway rats swimming, “but nothing was eating anything on camera”, she says. When a nationwide lockdown was announced in March 2020, Farnworth found her field season cut short and retrieved the streamside surveillance cameras. To her surprise, this last batch of footage solved the mystery, clearly showing the culprit—and it wasn’t a rat. The mussel munchers were pūkeko. Farnworth stresses that Norway rats aren’t exonerated. “We’re not saying that rats aren’t predating mussels; they could be. But we have identified something we know definitely does eat mussels: pūkeko.” In the footage, the pūkeko spy the mussels on the streambed, submerge their head to retrieve the shellfish with their beak, then carry it to the bank where they use their feet to hold the mussel and their beak to break through its shell to the tasty morsel inside. The pūkeko seemed to prefer the slightly smaller E. menziesii over the chunkier E. aucklandica, perhaps because E. aucklandica can bury itself deeper in the sediment and has a thicker shell. “If you’re after a quick snack, are you going to go for something with lots of complex wrapping, or are you just going to rip open a chocolate bar? If you’re a pūkeko, a thinner shell means less time spent getting food out,” says Farnworth. Pūkeko predation is yet another stressor—albeit a natural one—impacting kākahi populations. Loss of habitat, poor water quality and the decline of native fish (which play an important role as hosts in the kākahi life cycle) are the biggest factors driving freshwater mussel decline. “If it were just pūkeko predation, that wouldn’t be as much of an issue. But we’ve got multiple things impacting mussel populations,” says Farnworth. This means it’s important to consider pūkeko as part of kākahi conservation. We wouldn’t want a precious population of endangered mussels translocated to a new stream to be wiped out by a hungry bird.
Roads or streets?
During Auckland’s most recent lockdown, I got in the habit of going on a passeggiata. I called it this to make it seem more interesting; I went on a walk around the block. For Italians, a passeggiata is the stroll you take on a summer evening to see what’s happening in the town square and say hi to everyone else. For me, it meant putting a beer in the pocket of my cardigan and wandering down the road. I live in a suburb of Auckland known primarily for its giant spider sculpture and boy racers, and as I walked I found myself wishing there was somewhere to sit down and watch the world go past. Then I found myself wishing the world would go past in something other than cars, so that I could see it better. There’s a reason people-watching is a thing, and car-watching isn’t. I missed people-watching. In other words: there’s a difference between a road and a street. A road is a space for vehicles to travel on. A street is that, plus everything around it: the freesias sprouting underneath the neighbour’s fence, the loquats ripening on the berm, the kids walking to school, the buckets of fresh flowers and the stacks of bananas and taro outside the dairy, the flamingo tree, the tradie who stops me to ask directions to the giant spider. “It’s called Dale,” I tell him, and his face breaks into a huge grin. These are some of the reasons that I like walking—you see all the details that you miss when you drive. In this issue of the magazine, we explore what’s wrong with roads, and how we could start turning them back into streets. One of the biggest changes—and one with a lot of evidence in its favour—is to make it just as easy for people to walk or bicycle as it is to drive. Our drive-everywhere experiment, which New Zealand has been running since 1955, has had a good run. It’s had some anticipated consequences (crashes, noisy roads) and some unanticipated ones (social disconnection, carbon emissions). Cars have dominated our infrastructure spending and social habits for so long that we’ve really got no idea what our cities could be like if we made the other options just as good. We’d never make a road that was too narrow for a car, or that had a staircase in it, but there are plenty of places you can’t use a pram or a wheelchair. We’d never build subdivisions that weren’t connected by roads to the rest of the city, but we make new developments that aren’t served by public transport or that are unsafe for bicycles. Conversations about city transport often involve splitting people into teams. Drivers in this corner, cyclists in that corner. (Fight!) But I’m an advocate for dual citizenship. We’re never returning to some idealised state of prelapsarian carlessness—it smelled like manure back then—but we do have the ability to give New Zealanders more choices about how they move around. It’s not just about movement. When a space is filled with people rather than vehicles, there’s a life to it. In this age of social isolation, it’s more meaningful than ever to see each other’s faces, to nod at the familiar strangers of our neighbourhoods, to remind ourselves that humans are always weirder and more surprising than we expect—and that while we live apart, we also live in our cities together.
Too tasty for its own good
With its bright-red flowers shaped like a parrot’s beak, ngutukākā—also called kākābeak—is distinctive and delicious. Only 108 plants remain in the wild in Aotearoa, but many more grow in the United Kingdom due to the efforts of an English collector and gardener in the 1830s. Now, the descendants of these plants are returning home.
Snakes try something new
When an asteroid struck Earth 66 million years ago, three-quarters of all species became extinct, including the dinosaurs. This mass extinction triggered a remarkable burst of evolution, with survivors diversifying to fill ecological niches once occupied by dinosaurs. Among the survivors: the ancestors of today’s snakes. But unlike modern snakes, these ancient species were exclusively insect-eaters. Mathematical analysis of modern snakes’ diets allowed researchers to trace changes back through the evolutionary tree. They found that as bird and mammal populations exploded, snake diets expanded beyond bugs to include these warm-blooded vertebrates. This diversification gave rise to the 4000 snake species on Earth today—but none on land in New Zealand.
Minerals in the deep
In February, three mining companies were granted permission to explore the Cook Islands’ submarine wealth: lumps packed with rare metals on the sea floor. What has the tiny Pacific nation got to lose?
Less is more
Nelson Tasman’s innovative zero carbon itinerary allows travellers to do good things while supporting good businesses.
Ivory Lake Hut
This alpine hut on the West Coast was set up to house glaciologists, but as the ice has melted, it has been sought out by intrepid trampers.
A plague on all our houses
How one bacterium built our health system.
Gone fishing
If you had looked in the New Zealand Geographic office fridge in the summer of 2018 you would have found, next to the beer and the old film, a carefully wrapped plastic bag containing half a dozen transmitting GPS tags. Each one was worth thousands of dollars, and each was destined to be attached to a manta ray. Except no one knew where to find a manta ray. Department of Conservation marine scientist Clinton Duffy and Conservation International’s Mark Erdmann had assembled enough sightings of manta rays in New Zealand waters to know they visited. But the observations were spread from Cape Brett to Cape Colville, right on the edge of New Zealand’s territorial limit. Neither Duffy nor Erdmann could summon funding to investigate further at that time, so they were riding along on other boats doing other things—such as on photoshoots with New Zealand Geographic. It took a year to get the first tag into a manta ray, but then the animal immediately set a record for diving. By 2020, Erdmann had his own boat, and photojournalist Richie Robinson joined him to document the manta ray search. It involved a lot more looking than it did photographing. Richie spent 20 days on the water across two summers searching for manta rays before he was able to photograph one underwater. (Journalist Kate Evans, on the other hand, saw one on her third day.) All up, this issue’s cover story represents close to a month on the water for Richie. As this issue went to press, he was still out looking for manta rays—and not finding any. “I’m back to thinking mantas don’t exist,” he says.
