May 23, 2016

By Purbita Saha

To find out more about their ecological roles, seven moas were given a chance to live again (digitally, anyway).

Consider the moa, the flightless, Muppet-esque bird that once dominated the New Zealand landscape. The nine known moa species ranged greatly in size, from 12-foot-tall, 440-pound beasts to two-foot-tall, 60-pound darters. But they all met a similar fate, hunted to extinction in the 15th century by Polynesian settlers. Scientists knew a fair amount about the moas, including, thanks to some fossilized poop, what they ate. But they didn’t know how they ate. It may not seem so important, but when the moas vanished, they left a hole in the ecosystem; because there were no grazing mammals in New Zealand at the time, these large herbivores had played an outsized role in shaping the landscape, from thinning out vegetation to dispersing seeds. So to find out more about how the moas fed, a squad of scientists from Australia and New Zealand decided to use the magic of 3-D software (and an assist from a mummy) to digitally reconstruct the heads of several moa species, and then feed them a snack. Here’s how they did it.

Step 1: Build a Digital Skull

Using a computed tomography (CT) machine like you’d find in a hospital, the scientists generated scans of skulls taken from five different moa skeletons: an Upland Moa, a South Island Giant Moa, a Little Bush Moa, a Crested Moa, and a Coastal Moa. For comparison’s sake, they also scanned the skulls of an Emu and a Southern Cassowary, modern-day relatives of the moas (all are members of the ratite family). Then, using a technique called finite-element modeling, the scientists translated those medical image files into interactive digital 3-D models of each skull. Not all of the moa skulls were intact, so the team copied and pasted existing symmetrical pieces to fill in the holes, paying extra attention to the jawbones.
Step 2: Borrow Mummy Muscles

Step 1: Build a Digital Skull

The digitized Upland Moa skull. Digital Graphic: Courtesy of Marie Attard and The Royal Society Publishing

Using a computed tomography (CT) machine like you’d find in a hospital, the scientists generated scans of skulls taken from five different moa skeletons: an Upland Moa, a South Island Giant Moa, a Little Bush Moa, a Crested Moa, and a Coastal Moa. For comparison’s sake, they also scanned the skulls of an Emu and a Southern Cassowary, modern-day relatives of the moas (all are members of the ratite family). Then, using a technique called finite-element modeling, the scientists translated those medical image files into interactive digital 3-D models of each skull. Not all of the moa skulls were intact, so the team copied and pasted existing symmetrical pieces to fill in the holes, paying extra attention to the jawbones.
Step 2: Borrow Mummy Muscles

So how did the moas eat? Surprisingly, each moa species “appears to be using different feeding strategies, with some being more specialized than others,” says Marie Attard, a researcher at Sheffield College in England and leader of the study, the results of which were published earlier this year in the journal Proceedings of the Royal Society B. These different feeding styles, which may have evolved to reduce interspecies competition, would have, in turn, affected what the moas ate, where they lived, and what ecological role they played. Another takeaway? The moas had fed differently than the Emu and the cassowary. “There have been several politicians over the years that have advocated introducing large modern ratites into New Zealand to fulfill the ecological role of the moa,” says Attard. But her research suggests that when it comes to moas, there’s no substitute for the real deal—short of a Jurassic Park-style resurrection (see sidebar), the landscape the moa knew and shaped is gone for good.
What’s Better Than a 3-D Moa?

A live one. Lots of them, actually. Building moving moas on a computer is all well and good, but one New Zealand politician has a bolder proposition: repopulate the country with real live moas. Two years ago Trevor Mallard, a member of parliament from New Zealand’s left-leaning Labour Party, began arguing that scientists should resurrect the bird—or at least a hybrid version of it—using DNA pulled from well-preserved bones. And lucky for him, one local genius is already on the case. David Iorns, a software engineer, is collaborating with the Beijing Genomics Institute to sequence the extinct bird’s entire genome, in hopes of eventually bringing some version of it back to life. But Mallard does have one condition: “I only want the small moa,” he said during a presentation in the suburb of Wainuiomata. “I’d like ones that I could pat on the head.”