The moa and elephant bird were two of the largest birds to ever live. Both flightless giants inhabited islands in the southern hemisphere and went extinct shortly after humans arrived. But which of these mega-birds was bigger?
Quick Facts
Here are some key facts about the moa and elephant bird:
- Moa: Flightless birds native to New Zealand. Went extinct around 1500 AD.
- Elephant bird: Flightless birds native to Madagascar. Went extinct around 1000 AD.
- Largest moa species stood up to 12 feet (3.6 m) tall.
- Largest elephant bird species reached 10 feet (3 m) tall.
Based on their maximum heights, the tallest moa species edged out the elephant bird as the larger of the two. But height is just one measure of size. To get a more complete picture, we need to look at other dimensions as well.
Species and Sizes
There were several different species of moa and elephant bird, ranging widely in size. Here is an overview of some key species and their estimated dimensions:
Moa Species
Species | Height | Weight |
---|---|---|
South Island giant moa | 12 ft (3.6 m) | 510 lb (230 kg) |
North Island giant moa | 10 ft (3 m) | 440 lb (200 kg) |
Heavy-footed moa | 6.5 ft (2 m) | 120 lb (54 kg) |
Eastern moa | 4.9 ft (1.5 m) | 75 lb (34 kg) |
Elephant Bird Species
Species | Height | Weight |
---|---|---|
Aepyornis maximus | 10 ft (3 m) | 880 lb (400 kg) |
Aepyornis hildebrandti | 7.9 ft (2.4 m) | 550 lb (250 kg) |
Aepyornis medius | 4.9 ft (1.5 m) | 100 lb (45 kg) |
Aepyornis grandidieri | 4.3 ft (1.3 m) | 90 lb (41 kg) |
As the tables show, the largest elephant bird (A. maximus) was rivaled in height by New Zealand’s giant moa, but outweighed even the heaviest moa by over 300 pounds. The elephant bird’s massive size is believed to be an outcome of isolated evolution in the absence of mammalian predators.
Skeletal Evidence
In addition to height and weight estimates, skeletal remains provide further evidence for calculating the sizes of the moa and elephant bird. Key skeletal measurements include:
- Leg bones – Thicker, more robust leg bones can indicate a larger animal.
- Pelvis width – Wider pelvic openings suggest a wider torso and larger body mass.
- Skull length – Longer skulls typically mean larger heads and total body sizes.
Here’s how some key skeletal measurements of the moa and elephant bird compare:
Measurement | Largest Moa | Largest Elephant Bird |
---|---|---|
Femur (leg bone) width | 5.9 in (15 cm) | 7.8 in (20 cm) |
Pelvis width | 39.4 in (100 cm) | 59.1 in (150 cm) |
Skull length | 19.7 in (50 cm) | 31.5 in (80 cm) |
The elephant bird has noticeably more robust leg bones, wider pelvic width, and longer skull length compared to the moa. Together, this skeletal evidence points to Aepyornis maximus being larger than even the giant moa in overall body size.
Egg Sizes
One final way to gauge the sizes of the moa and elephant bird is to look at their egg dimensions. As with all birds, the moa and elephant birds grew inside eggs before hatching. By comparing their egg sizes, we can infer details about the relative sizes of the full-grown birds:
Measurement | Largest Moa Egg | Largest Elephant Bird Egg |
---|---|---|
Length | 13 in (33 cm) | 34 in (86 cm) |
Width | 8.3 in (21 cm) | 22 in (56 cm) |
Circumference | 21.6 in (55 cm) | 76 in (193 cm) |
Volume | 1.5 gal (5.8 L) | 16 gal (60 L) |
Weight | 7-9 lb (3-4 kg) | 22 lb (10 kg) |
In every dimension, Aepyornis eggs eclipse even the largest moa egg. The elephant bird egg is more than double the length and triple the weight of the biggest moa egg. By inference, this suggests the adult elephant birds were considerably larger than moa upon hatching.
Conclusion
So which giant bird was bigger – the moa or elephant bird? Based on the evidence for height, weight, skeletal size, and egg dimensions, the elephant bird was overall the larger of the two.
Aepyornis maximus edged out the tallest moa in height and far outweighed even the heaviest moa species. The elephant bird’s leg bones, pelvic width, and skull size also indicate a much bulkier animal than the moa. Finally, the elephant bird egg is substantially larger than the moa egg, reflecting the greater size of the adults.
In summary, the elephant bird was most likely the largest bird ever to walk the Earth. The moa was smaller but still reached impressive sizes, especially the 12 foot tall South Island giant moa. While both birds are now extinct, the evidence shows the elephant bird was the heaviest and largest member of this giant flightless duo.