The elephant bird and the moa were two flightless bird species that inhabited the Southern Hemisphere during the late Quaternary period. They share some similarities, which has led some people to wonder if they were actually the same species. However, the elephant bird (Aepyornithidae) and the moa (Dinornithiformes) belonged to two different taxonomic families and had distinct evolutionary histories and anatomical features.
Quick Answers
Where did the elephant bird and moa live?
The elephant birds were endemic to Madagascar, an island off the coast of southeast Africa. The moa inhabited New Zealand, an island country in the southwestern Pacific Ocean. So, the elephant bird and moa lived on islands thousands of miles apart.
When did they live?
Elephant birds went extinct around 1,000 years ago, with the last known species surviving until around the 13th century. Moa disappeared from New Zealand approximately 600 years ago after the arrival of the Maori people. There was an overlap in the time periods when both species inhabited the Earth.
How big were they?
On average, elephant birds were much larger than moa. The largest elephant bird species, such as Aepyornis maximus, stood over 10 feet tall and weighed 880 pounds. By comparison, the tallest moa was Dinornis robustus, which reached about 10 feet in height but only weighed around 500 pounds.
Were they related?
Genetic evidence indicates elephant birds and moa belonged to evolutionary lineages that diverged tens of millions of years ago. Elephant birds were most closely related to kiwi and emus, while moa share a more recent common ancestor with tinamous in South America. So, they were only very distant relatives.
Taxonomy and Evolutionary History
The elephant bird and moa belonged to distinct taxonomic families that arose independently through separate evolutionary histories:
Elephant Birds
Elephant birds, or Aepyornithidae, were large flightless birds that lived in Madagascar. There were several genera and species of elephant birds, including:
– Aepyornis – The largest elephant bird genus, including the giant A. maximus.
– Mullerornis – A medium-sized genus, with species around 6 feet tall.
– Flacourtia – The smallest elephant bird, about the size of a turkey.
Elephant birds belong to the ancient avian group called paleognaths, which includes flightless ratites like ostriches, rheas, cassowaries, emus, and kiwi. Molecular evidence indicates elephant birds were most closely related to the kiwi and emu lineages, diverging from them sometime in the Paleogene period around 40 million years ago.
Some taxonomists consider elephant birds to be giant ratites, while others place them in their own family Aepyornithidae separate from other ratites. Whatever their exact taxonomy, elephant birds represent a branch of Gondwanan ratites that evolved independently in isolation on the island of Madagascar for millions of years.
Moa
The moa were a diverse group of extinct flightless birds that inhabited New Zealand. There were nine valid species across six genera of moa:
– Dinornis – The largest moa genus, including the giant moa D. novaezealandiae.
– Emeus – Medium-sized moa around 6 feet tall.
– Euryapteryx – A smaller genus of stout, turkey-sized moa.
– Pachyornis – The heaviest moa with thick legs and short bills.
– Anomalopteryx – The smallest moa, similar to a kiwi.
– Megalapteryx – A rare genus known from a few fossils.
Moa belong to an ancient avian order called the Dinornithiformes. Molecular phylogenetics indicates moa are part of a branch of ratites called the Australaves, which originated in South America and later dispersed via Antarctica to Australia and New Zealand. The ancestors of moa diverged from the ancestors of their closest living relatives, the tinamous of South America, sometime in the Paleocene around 60 million years ago.
So moa represent an early Australasian lineage of ratites distinct from elephant birds and other Gondwanan ratites like ostriches and emus.
Geographic Distribution
Elephant birds and moa inhabited completely different landmasses separated by thousands of miles of open ocean:
Elephant Birds
All known elephant bird fossils have been found on the island of Madagascar off the southeastern coast of Africa. Madagascar was part of the ancient supercontinent Gondwana, but it separated from Africa about 160 million years ago. This isolation allowed unique flora and fauna like the elephant birds to evolve there.
There is no evidence elephant birds ever dispersed beyond Madagascar. They went extinct around 1,000 years ago, likely due to human hunting and habitat loss.
Moa
Moa fossils are found exclusively on the islands of New Zealand, an isolated landmass around 1,200 miles southeast of Australia. New Zealand split from Australia 80 million years ago, allowing the ancestral moa lineage to thrive there for millions of years.
Fossil sites and cultural evidence show moa once inhabited both North Island and South Island of New Zealand. Moa disappeared from New Zealand shortly after the arrival of Polynesian settlers 700-600 years ago.
Size Comparison
On average, elephant birds were much larger than moa. However, there was some overlap in size between the largest moa and smallest elephant birds:
Elephant Birds
Species | Height | Weight |
---|---|---|
Aepyornis maximus | 10 ft | 880 lbs |
Aepyornis hildebrandti | 8.2 ft | 450 lbs |
Mullerornis agilis | 6 ft | 220 lbs |
Flacourtia rudolfensis | 3.6 ft | 55 lbs |
The largest elephant bird, Aepyornis maximus, reached over 10 feet tall and weighed around 880 pounds. But smaller species were only around 3-4 feet tall.
Moa
Species | Height | Weight |
---|---|---|
Dinornis robustus | 10 ft | 500 lbs |
Dinornis novaezealandiae | 8.5 ft | 400 lbs |
Emeus crassus | 5.5 ft | 200 lbs |
Anomalopteryx didiformis | 2 ft | 25 lbs |
The tallest moa, Dinornis robustus, reached about 10 feet in height, but was slimmer than elephant birds at around 500 pounds. The smallest moa was under 2 feet tall.
So there was some overlap between the larger moa and smaller elephant birds. But on average elephant birds were the heavier birds, with some species weighing nearly twice as much as the largest moa.
Anatomy and Appearance
While sharing some superficial similarities, elephant birds and moa differed significantly in their detailed skeletal anatomy:
Elephant Bird Anatomy
– Extremely large and robust skeleton to support their massive size.
– Broad pelvis and sturdy legs with shortened trochlea.
– Large skull and massive down-curved beak.
– Long neck with 13 elongated cervical vertebrae.
Overall, elephant birds were very robust with skeletons adapted to support enormous weight. Aepyornis had especially shortened legs coupled with an enormous torso. Mullerornis had proportionally longer legs and neck.
Moa Anatomy
– Slender skeletons despite their large sizes.
– Narrow pelvis, small femoral heads and thin leg bones.
– Variable beak shapes from long and slender to short and downturned.
– Short necks with 12-13 cervical vertebrae.
Moa had much more delicate skeletal structure than elephant birds. Dinornis and Pachyornis had longer legs with proportionally small bodies. Emeus and Euryapteryx had shorter, thicker legs and larger bodies.
The differences in pelvic anatomy and leg bone robustness between elephant birds and moa were especially pronounced.
Behavior, Ecology and Diet
Elephant birds and moa were likely both herbivores that filled similar ecological niches, but their exact diets and behavior differed:
Elephant Birds
– Likely fed on small fruits, seeds, and vegetation close to the ground.
– May have been territorial omnivores that occasionally ate small vertebrates.
– Their large size may have deterred predators, but crocodiles and humans preyed on them.
– Probably laid very large eggs like other ratites.
– Sparse fossils offer limited information about behavior and ecology.
Moa
– Herbivores that browsed leaves, twigs, fruits and seeds of bushes and small trees.
– Had gizzard stones to grind tough plant material.
– Fill many ecological niches from forests to grasslands.
– Eggshell fossils indicate clutch sizes around 1-2 eggs.
– More abundant fossils and subfossils reveal details about diet and habitat.
While both were large herbivores, moa occupied more diverse ecosystems than the forest-dwelling elephant birds. More moa remains allow paleontologists to reconstruct their ecology.
Extinction
The elephant bird and moa both met their demise shortly after humans first arrived on their island homes:
Elephant Birds
– Survived in isolation until humans first settled Madagascar around 1,500-2,000 years ago.
– Hunting and habitat destruction by early human settlers likely drove all elephant bird species to extinction.
– Some reports indicate they may have survived until the 13th or 17th century.
– Most species were likely extinct by 1000 AD, or approximately 1,000 years ago.
Moa
– Flourished in New Zealand until Polynesians first arrived around 1250-1300 AD.
– Hunted aggressively by Maori settlers; they were extinct throughout New Zealand by 1500 AD.
– Habitat loss and predation by settler’s rats also contributed to extinction.
– Most species died out within 100-200 years of human settlement.
Both elephant birds and moa had no natural predators and were highly vulnerable to human over-exploitation due to their flightlessness. They represent some of the most recent extinctions of megafauna species.
Conclusion
While the elephant bird and moa were large, flightless birds that filled similar ecological roles, they clearly represent distinct species that evolved independently in isolation:
– Elephant birds and moa belonged to different taxonomic families with deep evolutionary divergences.
– They lived on landmasses thousands of miles apart with no biogeographical connections.
– Elephant birds were much larger on average than moa.
– They had pronounced differences in anatomy, proportions, and skeletal structure.
– Their behavior and ecology were somewhat different based on habitat differences.
– And they went extinct thousands of kilometers apart under similar circumstances.
So in summary, the elephant bird (Aepyornithidae) was endemic to Madagascar, while the moa (Dinornithiformes) was restricted to New Zealand. They represent a classic case of evolutionary convergence, where similar adaptations evolved independently in distant locations. Though superficially similar, the elephant bird and moa were quite distinct both evolutionarily and biologically. Their similarities were the result of convergent evolution on different continental land masses.