Wow! Actually Mamals Is Nocturnal, But Meteor Changes It

Kayentatherium, a dinosaur-era mammal. (Mark Witton / Recreating an Age of Reptiles)

Once upon a time the ancestors of mammals were nocturnal animals, animals that are active at night. But the asteroid hit that hit the earth and triggered the extinction of the dinosaurs unknowingly also changed the lifestyle of the predecessors of mammals.

A study published in Nature Ecology & Evolution revealed that after the event, mammals began to change in the daytime or diurnal life. "Frankly we are surprised by the correlation between the extinction of dinosaurs with the beginning of daytime activities in mammals," said Roi Maor, a researcher from the Tel Aviv University's Zoology School, as quoted by Inverse, Monday (6/11/2017).

The theory suggests that the ancestors of nocturnal mammals have existed for some time. Some scientists assume that ancient mammals lived nocturnal life because they could not compete for feeding with active dinosaurs during the day. Or ancient mammals want to avoid being eaten by dinosaurs themselves. But this is the first time the study was conducted. This study also tries to give the date when the transition begins.

The study was conducted by examining data of 2,415 species of mammals that exist today. Researchers from University College London and the Steinhardt Museum of Natural History in Tel Aviv use computer algorithms to reconstruct patterns of mammalian ancestral activity.
The results are found if there are two different mammal family trees, both of which reveal that these mammalian ancestors switched from nocturnal life to daytime life after the dinosaurs disappeared. The process occurs gradually over a million years.

"It is very difficult to link behavioral changes in mammals that have lived so long to ecological conditions as they are today, but we see a clear correlation in our findings," said Tamar Dayan, another researcher involved in the study.

The researchers found that simian ancestors were the first mammals to switch from nighttime to daytime activities. And now, simian has a visual acuity and color perception that is comparable to lizards and birds whose ancestors are always active during the day. "It shows monkeys and apes, including humans are the only mammals that develop their eyes like animals that live during the day or diurnal," he said.

But not all mammals then evolved like primates. As we see today there are also many nocturnal mammals. So the existence of this study eventually also answers why some mammals still have the ability to adapt and survive in the dark environment. Like for example antelope or other carnivores that have a keen sense of vision and smell that can support at night.


Source : Sains.kompas.com