Moa

Moa Meaning

Moa was a group of nine extinct flightless birds unique to New Zealand, divided into six genera. Dinornis robustus and Dinornis novaezelandiae, the two largest species, stood around 3.6 m (12 ft) tall with their necks outstretched and weighing approximately 230 kg (510 lb), whereas the bush moa was more about the size of a turkey. When Polynesians arrived in New Zealand around 1300, predictions of the Moa population ranged from 58,000 to 2.5 million.

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Moa is a member of the order Dinornithiformes, which is conventionally classified as ratite. The flighted South American tinamous, formerly thought to be a sister group to ratites, were discovered to be their closest cousins through genetic analyses. The nine species of moa have been the only ratites without wings, even if they did have vestigial wings. Until the arrival of the Mori, these were the largest terrestrial mammals and dominating herbivores in New Zealand's forest, shrubland, and subalpine environments, and were solely pursued by the Haast's eagle. Overhunting caused the Moa to become extinct within 100 years of human settlement in New Zealand.

Description:

Moa bird skeletons have generally been reconstructed in an upright position to give them a taller appearance, however,  examination of their spinal articulations suggests that they most likely held their heads forward like a kiwi. The horizontal position was indicated by the spine being linked to the back of the head rather than the base. This would have allowed them to feed on low-growing grass while also allowing them to elevate their heads to browse trees as needed. As a result, the height of larger moa has been reconsidered. Maori rock art, on the other hand, displays moa or moa-like birds (possibly geese or adzebills) with their necks upright, showing that moa was skilled in both neck postures.

There are no records of the noises moa produced, but fossil evidence could give us a sense of what they sounded like. The trachea of moa was supported by a series of tiny bone rings called tracheal rings. The discovery of tracheal elongation in at least two moa taxa (Euryapteryx and Emeus) revealed that their trachea extended up to 1 m long and created a huge loop inside the body cavity. They have been the only ratites reported to have this trait, which is also found in several other bird species such as cranes, swans, and guinea fowl. Deep resonant vocalisations which can travel vast distances are connected with this trait.

Evolutionary Relationships:

Tinamous, small terrestrial South American birds that can fly, are the moa's closest cousins. The kiwi, Australian emu, and cassowary have been previously considered to be among the most strongly related to moa.

Numerous species reported in the late 19th and early 20th centuries were centred on fragmentary skeletons and ended up having been synonyms. Although new research utilising ancient DNA retrieved from bones in museum collections reveal that separate lineages occur within some of these, only 11 species are officially recognised. The intraspecific fluctuation of bone sizes between glacial and interglacial times, and also sexual dimorphism across several taxa, have generated much confusion in moa classification. While new research utilising ancient DNA retrieved from bones in museum collections reveal that separate lineages occur within some of these, only 11 species are officially recognised. The intraspecific fluctuation of bone sizes between glacial and interglacial times, and also sexual dimorphism across several taxa, have generated significant confusion in moa classification. Instead, they were classified as subspecies in a 2012 morphological analysis.

A variety of cryptic evolutionary lineages have been discovered in many moa taxa, according to ancient DNA analysis. Megalapteryx benhami (Archey) and Megalapteryx didinus (Owen) are synonymized since their bones possess all key characteristics. A north-south cline paired with temporal variation could describe size discrepancies, with specimens being greater during the Otiran glacial epoch (the last ice age in New Zealand). Pachyornis mappini on the North Island has a similar temporal size variation. Similar regional and chronological considerations are able to justify a few of the other size differences in moa species.

The Miocene Saint Bathans Fauna contains the earliest moa fossils. These represent two species that are already rather large, based on several eggshells and hind limb parts.

Behaviour and Ecology

Waikanae Creek (1872), Manawatu River (1895), Napier (1887), Palmerston North (1911), Marton (1896), Rangitikei River (1939), and are underwater in Lake Taupo are among the eight moa trackways discovered in the North Island, containing fossilised moa footprint impressions in river silts (1973). Walking speeds of 3–5 km/h (1.75–3 mph) are estimated based on the spacing of these tracks.

• Diet:

Their food has been inferred from the fossilised components of their gizzards and coprolites, and also subsequently through morphological studies of their skull and beak and stable isotope examination of their bones. Moa ate a variety of plant types and parts, such as fibrous leaves and twigs from low shrubs and trees. Pachyornis elephantopus had a beak that looked like a pair of secateurs and might clip the fibrous leaves of New Zealand flax (Phormium tenax) and twigs with a diameter of at least 8 mm.

Moa inhabited an ecological niche previously inhabited by huge browsing mammals including antelopes and llamas in the other nations. According to some biologists, a variety of plant species have evolved to escape being eaten by moas. Plants with small leaves and a thick network of branches, including Pennantia corymbosa, and Pseudopanax crassifolius (the horoeka or lancewood), that have brittle juvenile leaves, are suitable instances of divaricating plants.

Moa animals consumed gizzard stones (gastroliths), that were kept in their muscular gizzards and provided a grinding action, which enabled them to ingest coarse plant material, similar to several other birds. These stones have been typically smooth spherical quartz pebbles, however, preserved moa gizzard contents have yielded stones of over 110 millimetres (4 in) in length. Gizzards of Dinornis can often hold several kilogrammes of stones. The gizzard stones were most likely chosen with care by Moas, who chose the hardest pebbles.

• Reproduction

The pairs of moa animal species known as Euryapteryx curtus / E. crassus/ E. exilis, Emeus huttonii, and Pachyornis septentrionalis / P. mappini had long been thought to be males and females. DNA collected from bone samples was analysed for sex-specific genetic markers, which corroborated this. 

Before 2003, there were three species of Dinornis: the South Island giant moa (D. robustus), the North Island giant moa (D. novaezealandiae), and the slender moa (D. novaezealandiae) (D. struthioides). D. struthioides have all been males, while D. robustus were mostly females, according to DNA. As a result, the three Dinornis species had been categorised as two species, one for each of the North Island (D. novaezealandiae) and the South Island (D. robustus); nevertheless, D. robustus contains three separate genetic lineages and may potentially be classified as multiple species, as stated above.

These birds, like so many other huge endemic New Zealand birds, have been K-selected, according to growth rings in the moa cortical bone. They have a low fertility rate and a protracted maturation period, requiring around 10 years to reach older age. Because giant moa bird Dinornis species required as long to mature as small moa species, their skeletal growth was rapid throughout their juvenile years.

There is no information to imply that moa had been colonial nesters. Moa nesting is frequently inferred from eggshell pieces found in caves and rock shelters, although there is little proof of the nests themselves. Moa nests had been discovered during 1940s excavations of rock shelters in the eastern North Island, that was characterised as "tiny depressions visibly scraped out in the soft dry pumice." Moa nesting material is also being discovered in rock shelters in the South Island's Central Otago region, in which the dry climate keeps preserved plant material that is used to construct the nesting platform. The nesting season was late spring to summer, based on seeds and pollen discovered in moa coprolites discovered among the nesting material.

Relationship with Humans

Extinction: 

The only predator of the moa even before the introduction of human settlers was the huge Haast's eagle. Before humans arrived, New Zealand was isolated for 80 million years and had very few predators, which meant that not only are its ecosystems vulnerable to foreign species, but the local species were often ill-equipped to deal with human predators.

Polynesians arrived around 1300, and all of the moa genera were quickly wiped out through hunting and, to a smaller extent, habitat loss due to forest clearance. By 1445, all moa, as well as Haast's eagle, that had depended on them for sustenance, had vanished. Polynesians arrived around 1300, and all of the moa genera became quickly wiped out through hunting and, to a smaller extent, habitat loss due to forest clearance. By 1445, all moa, as well as Haast's eagle, that had depended on them for sustenance, had vanished.

Some scholars have argued that a few Megalapteryx didinus might well have survived in distant parts of New Zealand into the 18th and even 19th centuries, although this theory is controversial. As late as the 1770s, certain Mori hunters reported to be hunting moa; however, these tales may have referred to a now-lost South Islander rite rather than actual moa hunting. Whalers and sealers reported witnessing huge birds around the South Island's coast, and in the 1820s, a man named George Pauley claimed to have seen a moa in New Zealand's Otago region.

Surviving Remains:

Joel Polack, a trader that stayed on the North Island's East Coast from 1834 to 1837, reported seeing "many enormous fossil ossifications" near Mt Hikurangi in 1838. He was certain that they have been emu or ostrich bones, observing that "the Natives add that in times long ago they acquired the traditions that very huge birds had existed, but that the shortage of animal food, and also the ease with which they could be entrapped, had caused their extinction." Polack also mentioned that he had heard from Mori that a "kind of Struthio" still thrived in the South Island's remote areas.

Dieffenbach also mentions a relic found near Mt Hikurangi, which he believes belonged to "a now-extinct bird named Moa (or Movie) by the Māori." The bird's first written name is 'Movie.'

In 1839, a Mori that had discovered a fragment of strange bone on a riverbank gave it to John W. Harris, a Poverty Bay flax trader and natural-history enthusiast. He presented the 15 cm (6 in) bone piece to his uncle, Sydney surgeon John Rule, who forwarded it to Richard Owen, who had been serving at the Hunterian Museum at the Royal College of Surgeons in London at the moment.

Feathers and Soft Tissues:

Several outstanding specimens of moa remains were discovered, including soft tissues (muscle, skin, and feathers) preserved by desiccation when the bird expired in a fairly dry location (for example, a cave with a constant dry breeze blowing through it). The majority of such specimens were discovered in New Zealand's driest region, Central Otago. These are some of them:

• Gold miners discovered dried muscle on bones of a female Dinornis robustus at Tiger Hill in the Manuherikia River Valley in 1864.

• Several Emeus crassus bones with muscle attached, as well as a row of cervical vertebrae containing skin, muscle, and feathers, were collected in 1870 from Earnscleugh Cave near Alexandra.

• A male D. giganteus' articulated foot, complete with skin and footpads, was discovered in a crevice on the Knobby Range in 1874.

• Megalapteryx didinus type specimen discovered near Queenstown in 1878.

• Pachyornis elephantopus lower limb with skin and muscle, taken from the Hector Range in 1884.

• In 1894, a whole feathered leg of an M. didinus was discovered in Old Man Range.

• Before 1949, the head of an M. didinus was discovered near Cromwell.

Outside of Central Otago, two specimens have been discovered:

• In the 1980s, a full foot of M. didinus was discovered in a cave on Mount Owen near Nelson.

• In 1980, a skeleton of Anomalopteryx didiformis was discovered in a cave in Te Anau, complete with skin, muscle, and feather bases.

In contrast to such specimens, loose moa feathers were recovered from caves and rock shelters in the southern South Island, and a rough estimate of the moa plumage was made based on such remains. The Old Man Range leg of M. didinus demonstrates that such a species was feathered down to the foot. This is probably an adaptation to residing in high-altitude, snowy habitats, and it can also be observed in Darwin's rhea, which resides in a related seasonally snowy environment.

Claims of Survival:

Since the late 1800s, and as lately as 1993 and 2008, there has been suspicion that certain moa could still live, especially in the wilderness of South Westland and Fiordland. The Department of Conservation has been actively interested in the 1993 storey, but the animal in a fuzzy photograph was recognized as a red deer. Although cryptozoologists continue to look for them, their claims and proof have received relatively little attention from specialists and are pseudoscientific. Alice Mackenzie met a giant moa she thought was a takahe in 1880, but when it was unearthed in the 1940s and Mackenzie realized what it appeared like, she recognized she saw something else. 

The rediscovery of the takah in 1948, after none had been sighted since 1898, demonstrated that rare birds could go unnoticed for long periods of time. The takah, on the other hand, would have been a much smaller bird than that of the moa, and it has been reinvented after its tracks were recognised no credible evidence of moa tracks has yet been discovered, and experts continue to believe that moa survival is highly unlikely, given that they would have had to live unrecognised for over 500 years in a region frequented by hunters and hikers.

Potential Revival:

The monster has been cited several times as a possible candidate for cloning rebirth. Because of its iconic significance, as well as the reality that it went extinct just a few hundred years ago and that considerable quantities of moa remains exist, it is frequently named with the dodo as a top contender for extinction. Ankoh Yasuyuki Shirota, a Japanese scientist, has done preliminary work with DNA extraction.

In mid-2014, New Zealand Member of Parliament Trevor Mallard claimed that bringing back certain smaller species of moa within 50 years was a plausible notion, reigniting interest throughout the moa's potential for rebirth. Many people laughed at the suggestion, but it was backed up by certain natural history professionals.