Top Ten Things
(extended dance mix)
1. They’re extinct.
Sure, we’d all like to imagine that there could be a few moa still lurking in an isolated corner. Every once in a while, somebody reports seeing one. But the chance of even a few moa surviving into the European era is slim; for a viable population to survive unnoticed is just ludicrous. These are big birds, people. We’ve had hunters and trampers combing every patch of bush for years now, and no physical evidence—footprint, dropping, photograph, recording—has been recovered. We’ve got more evidence for Bigfoot and the Loch Ness Monster, and they’re imaginary. And don’t start talking to me about the Ivory-Billed Woodpecker, OK?
2. Some were BIG.
Understandably, museums concentrate on the largest species, particularly Dinornis giganteus (now D. robustus), which stood about two metres high at the shoulder. But the average was about the size of an emu, something that could look you in the eye. Euryapteryx curtus was the smallest species, weighing about 20 kg—as big as good-sized turkey. (There’s a picture in the Gallery)
3. They were eaten to extinction.
The evidence for a massive and very speedy overkill of moa is overwhelming. There are numerous butchering and cooking sites identified by archaeologists, and many skeletons with the tastiest portions removed and the rest discarded. Maori introduced rats and dogs as well, which must have had some impact on moa and their chicks, but mostly it's a textbook case of humans overexploiting an easily-harvested resource. In some areas of New Zealand moa may have only lasted a couple of decades. This account is still controversial, and is sometimes dismissed as "Pakeha academic theory", but I think this reflects a desire to see Maori as natural conservationists and "noble savages", when they were just human beings.
4. There were 10 different species (not 13, or 26, or 38).
Last century many species were named and described based on single bones, and the tendancy of the time was to label every variant as a new species or subspecies. Joel Cracraft (Cracraft 1976) reorganised the classification into 13 species, and Phil Millener and Trevor Worthy in a series of papers whittled it down to 11. Then in 2003 two Nature papers showed that the largest moa were all females, and lumped the three Dinornis species into males and (bigger) females of Dinornis robustus (in the South Island) and D. novaezealandiae (North Island). Sorry, no more Dinornis giganteus (Dinornis maximus is as out-of-date as the Nehru jacket). So that makes ten. But a recent paper suggests there may actually be about 15 species, based on lineages of ancient DNA recovered from bones. Watch this space.
5. They were ratites.
The living ratites are the ostrich (Africa), emu (Australia), cassowary (Australia and New Guinea), rhea (South America) and kiwi (New Zealand). Extinct ratites are the elephant bird (Madagascar) and of course the moa. Ratites are classified with the South American tinamous in a group called the paleognaths. The ratites are spread across four continents, but they are all flightless. Were they split apart by continental drift, or did all the lineages independently become flightless after dispersing? Recent DNA work (Cooper et. al. 1992) suggests the latter, with New Zealand being colonized twice, first by moa-ancestors, and then (40 million years ago) by flying kiwi-ancestors crossing the Tasman. If they were flightless they must have paddled their little legs really hard.
6. Most lived in forest, not grassland.
Early descriptions of moa pictured them browsing the grasslands of the Canterbury Plains like cattle. This was overturned when stomach contents of moa trapped in swamps proved to be twigs and leaves of forest shrubs and trees. Even quite recently, though, some scientists were still arguing that at least half the moa species had to be open-country dwellers. The problem is that prior to Maori forest clearance New Zealand was almost entirely covered with dense forest right up to the treeline—the grasslands are a recent artifact. One species, however— Megalapteryx didinus, the Upland Moa—is known to have lived in the mountain tussock country, and we know from a remarkable mummified skeleton that it had feathers all the way down its legs for insulation.
7. They probably didn’t stand around with their heads in the air.
Early articulations of moa skeletons had them standing erect, legs straight, necks stretched vertically. This made them impressively tall. Most feathered museum reconstructions were of Dinornis robustus, the very biggest species, invariably with head stretched up and with a human dwarfed in comparison. Recently, though, some scientists carefully fitted together a moa vertebral column, keeping all the vertebrae at the ‘most natural’ angle to each other, and what emerged was an S-shaped spine with the head held at the same height as the back. Now, a large moa could undoubtedly rear up to a considerable height if it wanted to, but reconstructing every skeleton in that posture seems a bit misleading to me. Check your local museum—how are their moa?
8. You can still find their bones.
In the open, bones just weathers away, but in a dry, cool cave, or buried away from oxygen-loving bacteria in a swamp or sand dune they can survive in good condition for thousands of years. In New Zealand, we usually call these bones subfossils; they’re not made of stone like a true fossil. New Zealand has a very poor fossil record of land animals, and the oldest fossil moa bones are only a couple of million years old. Subfossil bones, in contrast, are sometimes abundant, and a researcher can build up a good picture of life 2000 or 10,000 years ago by digging in the right cave. If you’re lucky, you can even find mummified skin or feathers.
9. They aren’t the only extinct New Zealand bird.
Moa get all the glory, but a couple of dozen other bird species went extinct at the same time as them (and for much the same reason). New Zealand was home to Harpagornis, the world’s largest eagle, capable of killing an adult moa. We also had a pelican, a swan, a crow, an owlet-nightjar, a big harrier hawk, two flightless geese, a snipe, a coot, several flightless ducks and rails, a whole suite of little flightless wrens, and my favourite, the adzebill; big as a turkey, and looked like a cross between a chicken and a dodo. See the Worthy and Holdaway book for details.
10. Moa (sing. and pl.) is pronounced more like MORE than MOWER.
One moa, two moa, three moa. Maori doesn’t use ‘s’ for plurals, and since it’s one of the official languages of my country I try to use it properly when I can. Encouragingly, some moa researchers seem to agree with me in this. Ditto for pronunciation: You can say “there ain’t no moa moa”, but not “there’s a [lawn] moa in my garden shed!” This, at least, is the theory. It may be a while before most New Zealanders break a lifetime’s habit and stop talking about ‘extinct mowers.’