It was a Tuesday afternoon on October 18, 1839 when John Rule, an Australian physician, presented a bone to the eminent professor of comparative anatomy, Richard Owen, in his chamber at the Royal College of Surgeons in London. The bone had been obtained by Rule’s nephew, John Harris, from the area that is now Gisborne, New Zealand.
The letter Harris had left with his uncle stated that he had been told that the bone and others like it were found on the banks of rivers and belonged to an eagle-type bird that was now extinct. Professor Richard Owen, a man noted for his raw intellect yet cunning malevolence* against his rivals, was not impressed. He summarily dismissed the bone, which was a mere six inches long, as a portion of the thighbone of a large land animal such as cow. And it was certainly not from any type of eagle, whose bones are slim and delicate. This bone was short and chunky.
John Rule, who was an amateur anatomist himself, persisted in his presentation claiming that the bone indeed belonged to a monstrous bird. He pointed out that the marrow of the bone was made up of a honeycomb structure distinct to birds. Owen reluctantly agreed to examine the bone in more detail.
This was the Victorian age when exotic animal materials were being brought to London from all corners of the realm for examination and classification. Richard Owen was one of the premier practitioners of the new science of comparative anatomy, a main principle of which was ‘functionalism’. The size, shape and characteristics of a biological item determined its function, and conversely, the function of something predicted what it should look like. For example, the fact that an animal was a carnivore could be used to predict the size, shape and musculature of its jaw. And in the same manner, a jawbone of certain shape and proportions would by definition reveal that an animal was a carnivore and from that other characteristics of the animal could be surmised. Particularly as far as bones were concerned, every nub and protrusion told a story.
On further examination of that single six-inch bone fragment, Owen concluded that Rule was right; the bone was part of a thighbone from a large bird as large or larger than an ostrich. One month later Owen presented his case, staking his considerable reputation on it, to a skeptical Zoological Society in London.
“So far as my skill in interpreting an osseous fragment may be credited, I am willing to risk my reputation for it on the statement that there has existed, if there does not now exist, in New Zealand, a Struthious bird nearly, if not quite, equal in size to the Ostrich.”
His presentation was met with doubt and scorn. But the moa, a type of now-extinct flightless bird native to New Zealand, had been discovered.
When more bones were discovered over the following years, Owen was proved right and was able to reconstruct an entire moa. By tradition he also had the honor of giving it its scientific name calling it Dinornis novazealandiae, meaning the “prodigious”, “terrible” or “surprising” bird of New Zealand.
Moa existed on both the North and South Islands. The nine known species vary in size from that of a small turkey to the largest (Dinornis novazealandiae and Dinornis robustus) which were 12 feet in height and weighed about 510 pounds. These were the original quintessential Big Birds.
Moas are distantly related to the ratite group of birds that include rheas, ostriches, emus and cassowaries. Ratite means lacking a breastbone or keel. Unlike other flightless birds, moas have no vestigial wings. The flightless kiwi by comparison actually has small useless wings.
Moas have clawed feet with three toes and a small spur on their heels, bulky bodies with long necks topped with small heads. A 250 kg (550 lb.) bird would have a skull only 23 X 12.5 cm (9 X 5 inches) in size. They had poor eyesight and a good sense of smell. The eggs they laid were quite large; eggs from the largest species measure 9.6 x 7.1 inches. The female birds were generally twice as large as the males in what is termed reverse sexual-dimorphism.
Moas were forest dwelling. They had no teeth but rather tore off vegetation. Like some other birds digestion occurred in part in a gizzard, a specialized muscular stomach which actually contains stones and grit the animal has swallowed. Remains of giant moas have been found with up to 5 kg of rocks in their gizzards.
Despite all the pictures of moas with their necks extended which added to their impressive height, moas actually held their heads and necks down in a more S-shape.
What happened to the moa? Initially it was thought that the moa pre-dated the Maori since there was no history that any living Maori or known distant relative had actually seen a moa. In 1851, Walter Mantell, who was also responsible for the discovery of a great number of moa bones that also eventually made their way to Richard Owen back in London, made an interesting discovery on the South Island. He found an ancient Maori site with ovens and cooking stones and the bony remains of moas that had obviously been cooked and eaten. Man and moa had coexisted at least for a time.
Further finds filled in the details of the story with the extirpation of the moa being one of the saddest chronicles in New Zealand biological history. When the first Polynesian settlers arrived, a reasonable estimate is that there were one million moa in New Zealand. Within a mere one hundred years by about 1400, they were all killed. Evidence has been found of giant hunting camps particularly on the east coast of the South Island where tens of thousands of moa had been slaughtered.
How did large birds such as the moa evolve? Well, the obvious answer was that when New Zealand broke off from Gondwana 80 million years ago, a common ancestor remained on New Zealand and over millions of years evolved into the moa (and for that matter into the kiwi). This theory has been termed moa’s ark.
More recent DNA evidence contradicts this. The moa is most closely related to the tinamou, a South American bird, and the ancestor of the moa is felt to have reached what is now New Zealand from South America and Antarctica 20 million years after the breaking off. And from what you now know about New Zealand, you can understand how these large flightless birds seen no where else in the world evolved. With a total lack of land predators, evolutionarily speaking, there was no longer any reason to fly.
In the late 1800’s moa mania reached its peak. The large bird captured the imagination of the entire world and moa bones could be sold for a profit leading to the popular pastime in New Zealand of ‘fossicking’.
For a brief period during the 1890’s the moa became a New Zealand national symbol. New Zealand was the “land of the moa” and moas were also featured on advertising and in cartoons, but their status was soon supplanted by the iconic kiwi.
Finally, could moa still survive here in New Zealand? Could I be tramping somewhere in the mountains and come upon a moa? First, it is curious that for the 70 years prior to Owen putting moas on the map, there was not one person, European or Maori, who volunteered that they had seen a bird such as a moa. Alleged sightings of moas began to occur and coincided with the bird’s fame. A three-volume book, “Moa Sightings” by Bruce Spittle actually chronicles the various alleged encounters.
The most recent famous alleged sighting occurred in 1993 when three trampers including a former British Army Commando sighted what they believed was a moa. The snapped a photo. What do you think?
Unfortunately, it is felt that even if some species of moa had survived in remote areas of New Zealand, they would have by now been wiped out by land predators such as the stoat and weasel.
As presented here, the discovery and history of the moa seems relatively straight-forward, but in reality it was characterized by a raft of interesting characters and controversy that took years to sort out.
For a detailed exploration of this fascinating part of New Zealand history, I highly recommend Quinn Berentson’s excellent book, Moa—The Life and Death of New Zealand’s Legendary Birds, Craig Potton publishing, 2012.
* The famous Charles Darwin once described Owen as ‘spiteful, unfair, ungenerous, extremely malignant, false, rude, unjust, illiberal, and disingenuous’.
(5) From cenozoiclife.blogspot.com