Massive eggs were the most fragile of any bird (Pocket Science)
Some of the largest bird eggs in history were surprisingly also some of the most fragile. That’s the conclusion from Leon Huynen from Brisbane University, who has been studying the eggs of an extinct group of flightless birds called moas. These giants roamed New Zealand until the 14th century when they were wiped out by humans. Today, all that remains are bones and eggs but some of the broken shells have preserved traces of the moas’ DNA. Earlier this year, Australian scientists sequenced the genes of moas for the first time. Now, Huynen has used the same techniques to work out how these birds cared for their young.
By sequencing DNA from 69 shell fragments, he worked out which of the 10 species of moa had laid each egg. To his surprise, he found that several of the eggs were incredibly thin, including some belonging to two species of Dinornis, the heaviest of moas. These eggs were barely more than a millimetre in thickness, even though they were laid by female birds that weighed as much as 250kg. Their fragility is astounding. Even though the largest moa eggs were 80 times larger than those of a chicken, they were more prone to breaking than any egg from the 3,400 species of birds measured to date.
The reason for this fragility is unclear but regardless, the huge females couldn’t possibly have incubated the eggs by sitting on them; instead, that job fell to the males. When Huynen sequenced DNA from the outside of the shells, he only found male sequences. Among the moas’ modern relatives, like ostriches, emus and rheas, it’s the lighter male who incubates the eggs and rears the young. It seems that moa daddies shared the same burden.
However, moa eggs were so easily broken that even the lighter male might have shattered them. It’s possible that they built special nests but all the evidence so far suggests that they merely scraped a shallow depression in the ground and lined it with bark and coarse foliage. For the moment, we have no idea how these big birds incubated their young.
Reference: PNAS http://dx.doi.org/10.1073/pnas.0914096107
More on eggs
- Giant dinosaurs used the planet to warm their eggs
- An 60,000-year old artistic movement recorded in ostrich egg shells
- Sanajeh, the snake the ate baby dinosaurs
- Dinosaur daddies took care of their young alone
- DNA from the largest bird ever sequenced from fossil eggshells
Go Further
Animals
- How can we protect grizzlies from their biggest threat—trains?How can we protect grizzlies from their biggest threat—trains?
- This ‘saber-toothed’ salmon wasn’t quite what we thoughtThis ‘saber-toothed’ salmon wasn’t quite what we thought
- Why this rhino-zebra friendship makes perfect senseWhy this rhino-zebra friendship makes perfect sense
- When did bioluminescence evolve? It’s older than we thought.When did bioluminescence evolve? It’s older than we thought.
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
Environment
- Are the Great Lakes the key to solving America’s emissions conundrum?Are the Great Lakes the key to solving America’s emissions conundrum?
- The world’s historic sites face climate change. Can Petra lead the way?The world’s historic sites face climate change. Can Petra lead the way?
- This pristine piece of the Amazon shows nature’s resilienceThis pristine piece of the Amazon shows nature’s resilience
- Listen to 30 years of climate change transformed into haunting musicListen to 30 years of climate change transformed into haunting music
History & Culture
- Meet the original members of the tortured poets departmentMeet the original members of the tortured poets department
- Séances at the White House? Why these first ladies turned to the occultSéances at the White House? Why these first ladies turned to the occult
- Gambling is everywhere now. When is that a problem?Gambling is everywhere now. When is that a problem?
- Beauty is pain—at least it was in 17th-century SpainBeauty is pain—at least it was in 17th-century Spain
Science
- Here's how astronomers found one of the rarest phenomenons in spaceHere's how astronomers found one of the rarest phenomenons in space
- Not an extrovert or introvert? There’s a word for that.Not an extrovert or introvert? There’s a word for that.
- NASA has a plan to clean up space junk—but is going green enough?NASA has a plan to clean up space junk—but is going green enough?
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
Travel
- Could Mexico's Chepe Express be the ultimate slow rail adventure?Could Mexico's Chepe Express be the ultimate slow rail adventure?
- What it's like to hike the Camino del Mayab in MexicoWhat it's like to hike the Camino del Mayab in Mexico