biology

Moa

Moa is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Moa rather than just read about it. In short: Moa (order Dinornithiformes) are an extinct group of flightless birds formerly endemic to New Zealand. During the Late Pleistocene-Holocene, there were nine species, in six genera.

Key takeaways

Moa belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Moa to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Moa from memory before moving on to harder problems.

Reference excerpt

Moa (order Dinornithiformes) are an extinct group of flightless birds formerly endemic to New Zealand. During the Late Pleistocene-Holocene, there were nine species, in six genera. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about 3.6 metres (12 ft) in height with neck outstretched, and weighed about 230 kilograms (510 lb); the smallest, the bush moa (Anomalopteryx didiformis), was about the size of a turkey. Estimates of the moa population when Polynesians settled New Zealand circa 1300 C.E. range from 58,000 to 2.5 million. Moa are traditionally placed in the ratite group. Genetic studies have found that their closest relatives are the flighted South American tinamous, once considered a sister group to ratites. The nine species of moa were the only entirely wingless birds, lacking even vestigial wings, which all other ratites have. They were the largest terrestrial animals and dominant herbivores in New Zealand's forest, shrubland, and subalpine ecosystems until the arrival of the Māori, and were hunted only by Haast's eagle. Moa extinction occurred within 100 years of human settlement of New Zealand, primarily because of overhunting.

Etymology The word moa is a Polynesian term for domestic fowl. The name was not in common use among the Māori by the time of European contact, likely because the bird it described had been extinct for some time. Nevertheless, knowledge was passed down through traditional stories and proverbs, such as kua ngaro i te ngaro o te moa (lost as the moa is lost). The earliest written record of the name was by missionaries William Williams and William Colenso in January 1838; Colenso speculated that the birds may have resembled gigantic fowl. In 1912, Māori chief Urupeni Pūhara claimed that the moa's traditional name was te kura (the red bird). The North Island giant moa is also called kuranui.

Description

Moa skeletons were traditionally reconstructed in an upright position to create impressive height, but analysis of their vertebral articulations indicates that they probably carried their heads forward, in the manner of a kiwi. The spine was attached to the rear of the head rather than the base, indicating the horizontal alignment. This would have let them graze on low vegetation, while being able to lift their heads and browse trees when necessary. This has resulted in a reconsideration of the height of larger moa. However, Māori rock art depicts moa or moa-like birds with necks upright, indicating that moa were capable of assuming both neck postures.

No records survive of what sounds moa made, though some idea of their calls can be gained from fossil evidence. The trachea of moa were supported by many small rings of bone known as tracheal rings. These rings were preserved within some articulated skeletons, and shows that at least two moa genera (Euryapteryx and Emeus) exhibited tracheal elongation, where their trachea, up to 1 metre (3.3 feet) long, formed a large loop within the body cavity. They are the only ratites known to exhibit this feature, which is also present in several other bird groups, including swans, cranes, and guinea fowl. The feature is associated with deep resonant vocalisations that can travel long distances.

Feathers and soft tissues Several examples of moa remains have been found with soft tissues (muscle, skin, feathers) preserved through desiccation after the bird died at a dry site (for example, a cave with a constant dry breeze blowing through it); these specimens are a form of natural mummy. Most were found in the semiarid Central Otago region, the driest part of New Zealand, but others are known from outside the Central Otago region. These include:

Dried muscle on bones of a female Dinornis robustus found at Tiger Hill in the Manuherikia River Valley by gold miners in 1864 (currently held by Yorkshire Museum) Several bones of Emeus crassus with muscle attached, and a row of neck vertebrae with muscle, skin, and feathers collected from Earnscleugh Cave near the town of Alexandra in 1870 (currently held by the Otago Museum) An articulated foot of a male D. giganteus with skin and foot pads preserved, found in a crevice on the Knobby Range in 1874 (currently held by the Otago Museum) The type specimen of Megalapteryx didinus found near Queenstown in 1878 (currently held by Natural History Museum, London; see photograph of foot on this page) The lower leg of Pachyornis elephantopus, with skin and muscle, from the Hector Range in 1884; (currently held by the Zoology Department, Cambridge University) The complete feathered leg of a M. didinus from Old Man Range in 1894 (currently held by the Otago Museum) The head of a M. didinus found near Cromwell sometime before 1949 (currently held by Te Papa Tongarewa). A complete foot of M. didinus found in a cave on Mount Owen near Nelson in the 1980s (currently held by Te Papa Tongarewa) A skeleton of Anomalopteryx didiformis with muscle, skin, and feather bases collected from a cave near Te Anau in 1980.

In addition to these specimens, loose moa feathers have been collected from caves and rock shelters in the southern South Island, and based on these remains, some idea of the moa plumage has been achieved. The preserved leg of M. didinus from the Old Man Range reveals that this species was feathered right down to the foot. This is likely to have been an adaptation to living in high-altitude, snowy environments, and is also seen in the Darwin's rhea, which lives in a similar seasonally snowy habitat. Moa feathers are up to 23 cm (9 in) long, and a range of colours has been reported, including reddish-brown, white, yellowish, and purplish. Dark feathers with white or creamy tips have also been found, and indicate that some moa species may have had plumage with a speckled appearance.

Classification

Evolutionary relationships

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Moa

Start with the simplest possible case. Write down what Moa claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Moa before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Moa ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Moa

In research: Moa appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Moa in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Moa is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animals with only two limbs, Bird extinctions since 1500, Dinornithidae, so understanding it makes those chapters shorter.
In everyday life: Look for Moa outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Moa in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Moa means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Moa out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Moa in simple terms?

Moa (order Dinornithiformes) are an extinct group of flightless birds formerly endemic to New Zealand. During the Late Pleistocene-Holocene, there were nine species, in six genera.

Why does Moa matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Moa?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Moa.

Moa