This Was The Biggest Land Animal On The West Side

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If you could visit the west side 5,000 years ago, you’d see a turkey-sized duck wandering around munching on plants.

We know the moa-nalo lived here because scientists have found its bones in Kalaeloa. It was three feet tall, weighed around 15 lbs — about the same as a Thanksgiving turkey — and ate a vegetarian diet.

Birds Were The West Side’s Biggest Land Animals For Millions Of Years

Hawaii didn’t have any land-based mammals until humans invented boats to get here. Until that point, the only arrivals were animals who could fly or swim thousands of miles on their own.

Birds were the first large animals to get here. When they arrived, the islands would have had ample grasses and ferns. On the continents, grasses and ferns were food for deer or goats. But since Hawaiʻi didn’t have any, the moa-nalo said: Don’t mind if we do!

The moa-nalo evolved, starting about 3.6 million years ago, from small ducks who must have gotten blown off course during migration. Over thousands of years the ducks grew bigger (which tends to happen on islands) and started eating the grasses and ferns that no other animals were.

Eventually the moa-nalo lost the ability to fly — they didn’t really need it.

The stilt-owl was another mostly terrestrial bird you’d see. This long-legged bird hunted smaller birds on foot—though they could fly if need be.

This animation by Pawel Nuckowski of Oʻahu Films imagines how the stilt owl might have looked.

How We Know About The Moa-Nalo, And Why It’s Extinct

We know these birds lived here because scientists have found their bones. I say “bones,” rather than “fossils,” because they died out fairly recently.

Wrote the scientists who found them: “Chemically they are essentially modern bone, little altered from their original composition when once part of a living organism.”

These birds, and many others, went extinct within the last 1,000 years, which coincides with the arrival of that boat-making animal species we mentioned earlier.

Science’s best guess is that the humans — or the pigs, dogs, or rats who hitched rides on their boats — hunted and ate the birds out of existence.

In any case, by 200 years ago, when humans started recording the types of animals they saw on these islands with another invention, writing, the moa-nalo and many others were not to be found.

Happily, the exposed reefs in Kalaeloa, with their sinkholes and caves, hid their bones so we could find out about them.

References

Ornithological Monographs No. 45 and No. 46: Descriptions of 32 New Species of Birds from the Hawaiian Islands.(This paper, by Helen F. James and Storrs L. Olson, is a milestone in biological archaeology. To find and describe a single previously unknown species is a massive achievement in the biology world. To find 32 of them is unheard of. Many of the species were found in the Kalaeloa area.)

Relationships of the extinct moa-nalos, flightless Hawaiian waterfowl, based on ancient DNA, by Michael D. Sorenson, Alan Cooper, Ellen E. Paxinos, Thomas W. Quinn, Helen F. James, Storrs L. Olson and Robert C. Fleischer.

Hawaiian Natural History, Ecology, and Evolution, by Alan Zeigler.

Photo illustration above uses drawing by Stanton F. Fink, used via Creative Commons license.