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The islands breed strange animals. Isolated from the rest of the world, these ecosystems often produce creatures specially adapted to their particular environment. Nations like Madagascar and New Zealand can thus lead a surprisingly similar life despite different climates.
So, while most birds in the world depend primarily on vision, Madagascar and New Zealand have some strange additions. Or in some cases, had.
Although the phrase "elephant bird" probably evokes images of emu or ostrich, a recent study published in Acts of the Royal Society B suggests that these extinct giants had more in common with the kiwi. Both were unable to fly and, according to the new study, were mostly blind and nocturnal. This corresponds to what you might think of a kiwi. They are tiny, with tiny fluffy brown feathers and oversized eggs compared to their bodies – you might even call them idiots. The fact that they can barely see and roam the night in the New Zealand bush in search of larvae jives with their image.
But the elephant birds were huge. At a height of 10 feet and a weight of half a ton – it's more than two SUVs – it was the biggest birds in the world. already. Imagine Big Bird, but increase it by more than two feet and make it more reptilian, then push it into a dense wood at night, walking blindly. That's what elephant birds looked like. (A species of elephant bird is literally named after the Malagasy word meaning "big bird".)
Most of this is a recent revelation. Fossils of this extinct family are rare and researchers at the University of Texas at Austin digitally reconstructed the brains of two skulls of elephant birds; They came to this conclusion by examining the olfactory bulb and the optical lobes, where the smells and images are processed, and finding that the balance was different than that of an average bird. Most avian species depend primarily on vision to navigate and hunt their prey. Consequently, their optical lobes are well developed in relation to their olfactory bulbs. This is even true for nocturnal species. Owls hunt at night and their evolutionary strategy is to increase their night vision capabilities to see in the dark.
But elephant birds, like kiwis, have olfactory bulbs much larger than their optical lobes, suggesting that they depend more on smell than on sight. In fact, they have virtually no optical lobes. This means that the birds would have been almost blind.
Although the idea of a huge bird that crushes in the undergrowth is hilarious enough, it is unlikely that these monsters had no problem navigating in the woods. As the authors of this recent article point out, some wild kiwifruit are completely blind, but their overall fitness does not diminish. They have somatosensory, olfactory and auditory systems so complex that they can move very well in the dark, much like bats (except without sonar). Researchers suspect that elephant birds may not have been quite the evolutionary ace of kiwifruit, but were obviously adapted enough to survive. Elephants have even managed to stay after the start of human settlement in Madagascar, a feat that many island birds, such as the New Zealand moa, have failed to accomplish. A combination of human intervention and habitat loss seems to have killed them in the 1600s, but no one is completely sure.
After all, until this newspaper, no one had ever doubted that a bird of this size would be blind. We clearly have a lot to learn.
This discovery will help researchers understand the evolutionary tree that spawned kiwis, elephants, emus, cbadowaries, moas, rheas, and tinamous (a family of birds living in Mexico, in America). Central and South America). This group, palaeognathae, is the sister clade of all other living birds, making them useful tools for understanding how all birds have appeared.
They are also just strange. "The evolution of Palaeognath has been marked by repeated gains in gigantism, helplessness, island endemism and twilight / nocturnality," the authors note. They then explain that losing sight of the olfaction could be a trait reserved for landbirds living on predator-free islands, because "only nocturnal birds unable to fly on the islands are known to reduce the system. visual in favor of the other senses. "In the absence of large mammals or reptiles to eat them, birds could evolve to detect their prey in another way, without having to worry about having to spot a potential predator.
We still know very little about these huge weirdos, and researchers hope that their discovery will spur further investigation on multiple species of elephant birds. Who knows what surprises might be hidden under all these feathers.
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