Drudge Retort: The Other Side of the News
Wednesday, November 08, 2017

Mammals only started being active in the daytime after non-avian dinosaurs were wiped out about 66 million years ago (mya), finds a new study led by UCL and Tel Aviv University's Steinhardt Museum of Natural History.

A long-standing theory holds that the common ancestor to all mammals was nocturnal, but the new discovery reveals when mammals started living in the daytime for the first time. It also provides insight into which species changed behaviour first.

The study, published today in Nature Ecology & Evolution, analysed data of 2415 species of mammals alive today using computer algorithms to reconstruct the likely activity patterns of their ancient ancestors who lived millions of years ago.

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Two different mammalian family trees portraying alternative timelines for the evolution of mammals were used in the analysis. The results from both show that mammals switched to daytime activity shortly after the dinosaurs had disappeared. This change did not happen in an instant – it involved an intermediate stage of mixed day and night activity over millions of years, which coincided with the events that decimated the dinosaurs.

"We were very surprised to find such close correlation between the disappearance of dinosaurs and the beginning of daytime activity in mammals, but we found the same result unanimously using several alternative analyses," explained lead author, PhD student Roi Maor (Tel Aviv University and UCL).

The team found that the ancestors of simian primates – such as gorillas, gibbons and tamarins – were among the first to give up nocturnal activity altogether. However, the two evolutionary timelines varied, giving a window between 52-33 mya for this to have occurred.

This discovery fits well with the fact that simian primates are the only mammals that have evolved adaptations to seeing well in daylight. The visual acuity and colour perception of simians is comparable to those of diurnal reptiles and birds – groups that never left the daytime niche.

Comments

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And dok know because he was there.

#1 | Posted by Sniper at 2017-11-08 11:31 AM | Reply | Newsworthy 1

dinos went Pffft?

#2 | Posted by ichiro at 2017-11-08 02:41 PM | Reply

As in, pfffft, finished, over, done, outta here..

#3 | Posted by Doc_Sarvis at 2017-11-09 07:15 AM | Reply

They got this by studying current animal behaviour and somehow modelling historic behaviour with that. Sounds pretty fluffy. There wasn't any fossil evidence involved.

#4 | Posted by Snowfake at 2017-11-09 07:28 AM | Reply

And that's why it makes so much sense to create a Jurassic Park. Give those Dino's a second chance at humans..

#5 | Posted by boaz at 2017-11-09 12:57 PM | Reply

You got it sno. They make stuff up.

#6 | Posted by Sniper at 2017-11-09 01:59 PM | Reply

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