Thinnest eggs belonged to largest Moas

August 31, 2010, weblog

Giant Haast's eagle attacking New Zealand moa. Artwork: John Megahan. Copyright: PLoS Biology. Via Wikipedia.
( -- In a detailed online study published by the Proceedings of the National Academy of Sciences on August 30th, scientists investigate questions surrounding New Zealand's moa eggs and the results are mystifying.

The 10 known species of moas, extinct relative of the ostrich and emus, were believed to be widely diverse in size varying from a small turkey-size to eight feet tall and beyond. For over a century, scientists and esteemed colleagues have studied 36 delicate, thin-shelled , discovering a few of which belonged to two of the largest, heaviest flightless bird species. Scientists scrutinized DNA from various moas found throughout New Zealand and compared each to eggshells. Their findings concluded the two thinnest eggshells belonged to the largest, heaviest female moas, Dinornis robustus and Dinornis novaezealandiae.

This begs the question, how did these giant creatures incubate such delicate eggs -- without breaking them?

With shells ranging from only 1.41-1.06 millimeters thick, it seems implausible for an adult female moa, weighing more than 550 pounds, to safely and effectively incubate such fragile eggs.

One theory based on trace is that male moas, weighing in at around 165 pounds, might have been responsible for incubation and caring for the young, much like the ostrich and emu. Though, it's been said the process would have been very difficult and hasn't yet been proven. Out of the 3,434 bird species studied both living and extinct, moa eggs are the most vulnerable to breakage, thus adding to the possibility that they had very unusual nesting habits.

Researcher David Lambert, an evolutionary biologist at Griffith University in Australia who was part of the investigation, told Live Science that nests weren't uncommon in the way they were built. With nothing but a mere scrape in the ground surrounded by a thin layer of twigs and leaves, this is something else the moas might have had in common with ostrich and emu relatives. Lambert also added it's been thought the moas may have curled around the eggs to warm them, instead of sitting directly on top of them to keep from obliterating their unborn offspring.

Moas were killed off into extinction once the Maori colonized in New Zealand in the late 13th century, but their size mixed with curious and nesting habits are a mystery scientists hope to someday solve for good.

Explore further: Extinct moa rewrites New Zealand's history

More information: Ancient DNA reveals extreme egg morphology and nesting behavior in New Zealand's extinct moa, Proceedings of the National Academy of Sciences, Published online before print August 30, 2010, doi:10.1073/pnas.0914096107

Related Stories

Extinct moa rewrites New Zealand's history

November 18, 2009

( -- The evolutionary history of New Zealand's many extinct flightless moa has been re-written in the first comprehensive study of more than 260 sub-fossil specimens to combine all known genetic, anatomical, geological ...

Scientists tease DNA from eggshell of extinct birds

March 9, 2010

( -- In a world first, scientists in Australia announced on Wednesday they had extracted DNA from the fossilised eggshells of extinct birds, including iconic giants such as the moa and elephant bird.

Scientists 'rebuild' giant moa using ancient DNA

July 1, 2009

( -- Scientists have performed the first DNA-based reconstruction of the giant extinct moa bird, using prehistoric feathers recovered from caves and rock shelters in New Zealand.

Recommended for you

How our cellular antennas are formed

January 17, 2019

Most of our cells contain an immobile primary cilium, an antenna used to transfer information from the surrounding environment. Some cells also have many mobile cilia that are used to generate movement. The 'skeleton' of ...

Individual lichens can have up to three fungi, study shows

January 17, 2019

Individual lichens may contain up to three different fungi, according to new research from an international team of researchers. This evidence provides new insight into another recent discovery that showed lichen are made ...

Sea slug study illuminates how mitochondria move

January 17, 2019

Your cells have an amazing ability—they can build their own energy factories, called mitochondria. Once built, mitochondria must move where needed in the cell. Defects in mitochondrial transport are a suspected cause of ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Sep 01, 2010
The 10 known species of moas, extinct relative of the ostrich and emus, were believed to be widely diverse in size varying from a small turkey-size to eight feet tall and beyond.

Saw this and just had to make it known. The Moa is not a relative of the ostrich or the emu. Furthermore, the ostrich and emu are not relatives of each other.
not rated yet Sep 01, 2010
The fate of the moa is similar to the fate of mega fauna around the world. In that contact with man meant extinction soon after.

Further to the relative comment above I am surprised that it appears to have been attributed to researcher David Lambert, an evolutionary biologist at Griffith University. I would think that any researcher of evolutionary biology would be well aware of the ancestry of the species being studied.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.