A huge footprint with three fingers marked on the ground recalls the passage of the great dinosaurs through our land. But it has been many millions of years since the dinosaurs became extinct. The creator of this imprint survived one of the great mass extinctions. But now he tries to flee from a new danger: a bipedal being that carries ropes and spears. Until then, the moa only feared an eagle attack, but the new inhabitant of his island is making his life miserable.
New Zealand’s giant “ostrich”
The dinornitiformes or moas were flightless birds that lived in New Zealand from the Cretaceous, more than 90 million years ago, until the year 1500 AD. C. approximately when they were extinguished by human action.
A dozen species of various statures are known. From Euryapteryx curtus , which was barely the size of a rooster, to Dinornis robustus , the giant moa that could reach 3.5 meters in height and weigh 250 kilos , taller and significantly heavier than current ostriches, which are around 180 kilos. The females were much larger than the males, to the point that they were considered different species until this notable sexual dimorphism was verified and what had been two until then had to be grouped into the same species.
We could find birds very similar to ostriches. However, although more robust, the moas have a clear difference: during their evolution they lost their wings , so their body lacks front limbs. On the contrary, they had very powerful legs and a long neck that would be carried more horizontally, although in recreations it usually appears in a more vertical position, in the manner of ostriches.
Moas were herbivorous animals. They ate ferns, branches and seeds, in addition to, as with other birds, swallowing small pebbles that help to grind their food once it was deposited in the gizzard.
A paradise to live
After the extinction of the dinosaurs and with continental drift, the moas benefited from an isolation that led to their speciation, evolving to giant species. Until the arrival of man, the islands of New Zealand had hardly any mammals except for a couple of species of bats and marine mammals. But it was not in danger from terrestrial predators that could hunt the vast majority of birds that inhabited the islands . This circumstance allowed the development of non-flying bird species, some with great success, such as the moas, which reached enormous sizes and spread over much of the New Zealand islands.
Haast’s eagle ( Hieraaetus moorei ), the largest known eagle in Earth’s history, was the only predator the giant moas had. But the situation changed drastically with the arrival of the human being.
moa extinction
Polynesians arrived in New Zealand between 800 and 1300. Humans are usually accompanied by two groups of loyal followers, in this case the Polynesian dog and the Polynesian rat. A predator and a rodent that had a tremendous impact on the native fauna.
Dinornis robustus was adapted to avoid overpopulation on the island. It took ten years to reach reproductive maturity (current ostriches live between 30 and 40 years). This natural defense of the giant moa was a burden that only contributed to its extinction due to a reproduction rate that was unable to sustain the rate of Maori hunting . Around 1500 AD C. we no longer have evidence of living moas.
A New Zealand icon
Currently, the moa is in a context of dusting off, study and recognition as an icon for the new generations of New Zealand. Traditionally, New Zealanders have been receiving a Eurocentric education, under the premise that they were an insignificant element of the Commonwealth. But that point of view has changed and today a native and own history is claimed, as opposed to the past linked to imperialist ambitions. That is why local elements have gained strength as symbols to be better known and exhibited. Among them, the moa stands out, which gives its name and logo to shields, shops and even a brand of beer.
References:
Baker, A. et al. 2005. Reconstructing the tempo and mode of evolution in an extinct clade of birds with ancient DNA: The giant moas of New Zealand. PNAS 102, 23, 8257-8262. DOI: 10.1073/pnas.0409435102.
Martínez, G. 2020. The moa, from extinct animal to symbol of New Zealand. Travel.nationalgeographic.com.
Turvey, S. and Holdaway, R. 2005. Postnatal ontogeny, population structure, and extinction of the giant moa Dinornis. Journal of Morphology 265, 1, 70-86. DOI: 10.1002/jmor.10341.c
