Chinese fossil shows owls 'rejected night for fun in the sun'
A Chinese-led research team have made what they say is the first discovery of a fossil skeleton of an owl that lived more than six million years ago and was active in daytime.
Most owl species are active at night, but a few are diurnal - active during the day and resting at night.
The researchers analysed eye bones from the fossil - found in China near the Tibetan Plateau - alongside those of other birds and reptiles. They found that the extinct owl was a member of the Surniini group, which includes most diurnal owl species.
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The study was published on Monday in peer-reviewed journal Proceedings of the National Academy of Sciences.
Li Zhiheng, the lead author of the study and a researcher with the Chinese Academy of Sciences (CAS), said the fossil was the first trace of an ancient daytime-active owl.
"There were previous studies on owl fossils, but they didn't analyse their behaviour and didn't know clearly about their evolutionary history," he said.
"Our study is the first comprehensive analysis of the evolution of nocturnal and diurnal owls."
Thomas Stidham, a co-author of the study and also a researcher at the CAS, was quoted as saying by the institution that the fossil was the first record of an evolutionary process spanning millions of years and stretching across the globe, during which some owls evolved to "reject the night for some fun in the sun".
The ancestors of the owls were all nocturnal, but a small group of species evolved with diurnal habits, Li said.
The fossil was found in the Linxia Basin in Gansu province, close to the northeastern edge of the Tibetan Plateau. It had preserved nearly the entire skeleton from head to feet, and included the tail bone, the researchers said.
Their report said that they analysed the owl's eye bones and compared their characteristics with those of about 360 species of bird and 55 species of reptile, which led them to find that the own was diurnal.
They carried out statistical analysis on behavioural data from the bird species, including owls, and found that the extinct owl's ancestors had evolved from nocturnal to diurnal habits.
"Their results show that the ancestor of all living owls was almost certainly nocturnal, but the ancestor of the Surniini group was instead diurnal," the CAS said.
Li said the evolution of diurnal owls might be linked to changes in the climate and environment in the Tibetan Plateau region, but that this was not yet proven.
"We will keep researching other bird species in the region and discovering their relationship to ecology and biodiversity," he said.
This article originally appeared on the South China Morning Post (SCMP).
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