LIKE a modern owl, Archaeopteryx may have come alive at night. The shapes of eye sockets differ predictably in birds that feed during the day, night or twilight, according to a study that promises to spill the beans on the dino-bird鈥檚 lifestyle.
When Lars Schmitz at the University of California, Davis, studied 77 bird species, he found he could predict the foraging lifestyle of any species simply by measuring the bones that their eyes are set in. Each bird pupil is surrounded by a ring of bony segments called the scleral ring. Schmitz found that the outer and inner diameter of this ring, combined with the depth of eye sockets, could closely predict when a bird forages (). This opens up the tantalising possibility of discovering whether extinct birds were nocturnal.
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Schmitz is currently making detailed measurements, but a quick look at Archaeopteryx fossils reveals that it had wide scleral rings and deep eye sockets, says at the University of Manchester. According to Schmitz鈥檚 findings, this would make the dino-bird nocturnal.
鈥淚 don鈥檛 think it had occurred to anyone to suggest this,鈥� says Yalden. If he is right, all drawings of Archaeopteryx flying through the daytime skies of early Earth will need to be revisited.
