mammals gave up night life only
Last Updated : GMT 09:40:38
Themuslimchronicle, themuslimchronicle
Themuslimchronicle, themuslimchronicle
Last Updated : GMT 09:40:38
Themuslimchronicle, themuslimchronicle

after dino doom

Mammals gave up night life only

Themuslimchronicle, themuslimchronicle

Themuslimchronicle, themuslimchronicleMammals gave up night life only

Squirrels, like many carnivores, have a keen sense of smell and acute hearing
Paris - Muslimchronicle

The earliest mammals were night creatures which only emerged from the cover of darkness after the demise of the daytime-dominating dinosaurs, researchers said Monday.

This would explain why relatively few mammals follow a daytime-active or "diurnal" lifestyle today, and why most that do still have eyes and ears more suitable for living by night.

"Most mammals today are nocturnal and possess adaptations to survive in dark environments," study co-author Roi Maor of the Tel Aviv University told AFP.

"Monkeys and apes (including humans) are the only diurnal mammals that have evolved eyes that are similar to the other diurnal animals like birds or reptiles. Other diurnal mammals have not developed such profound adaptations."

Maor and a team provide evidence for a long-standing theory that tens of millions of years of evading dinosaurs caused a nocturnal "bottleneck" in the evolution of mammals -- the group of warm-blooded, milk-producing creatures that includes our own species.

Because they hid out in darkness for so long, possibly to avoid competition with dinos for food or territory, or being eaten by them, mammals today are not quite on par with fish, reptiles and birds when it comes to daytime vision.

Mammals, apart from primates, lack a part of the eye known as the fovea, which many fish, reptiles and birds have and is replete with photoreceptor "cone" cells for seeing colour in high light.

Instead, they tend to have more "rod" cells, which can pick up scant light in dim conditions, but provide relatively low resolution.

Modern-day mammals which are active mostly by day -- including types of squirrel, tree-shrews, some antelope and many carnivores -- also still tend to have a keen sense of smell and acute hearing, attributes required for living in the dark.

- Primates first -

Maor and a team analysed the lifestyles of 2,415 living mammal species, and used computer algorithms to reconstruct the likely behaviour of their ancestors, and their ancestors before them -- going back to the very beginning of mammals.

The earliest mammal ancestor emerged between 220 million and 160 million years ago, evolving from a reptilian forebear. And it was probably nocturnal, according to the study published in the journal Nature Ecology & Evolution.

Dinosaurs, on the other hand, were likely day-dwellers seeking out sunlight to warm their bodies like reptiles today.

The data revealed that mammals remained nocturnal throughout the Mesozoic period, which ended about 66 million years ago when a massive calamity, possibly an asteroid strike, wiped out the dinos and about three-quarters of life on Earth.

Mammals, then mainly small, scurrying animals, survived, and flourished.

Most stayed nocturnal, some embraced the daytime, and others -- including cats, elephants and cows -- are today a bit of both.

Primate ancestors were among the first mammals to become strictly diurnal -- possibly as long as 52 million years ago -- the researchers found.

This explains why our primate family is better adapted to the sunlit way of life -- we've had more time to evolve and adapt.

The reason for the shift from night to day is not clear, said Maor, but may have included a "reduced risk of predation" to early mammals.

The study, while showing a strong correlation between the death of dinos and the daytime emergence of mammals, cannot conclude that one led to the other.

source: AFP

themuslimchronicle
themuslimchronicle

GMT 08:14 2018 Sunday ,14 January

Fossil fuels blown away by wind

GMT 08:56 2018 Tuesday ,09 January

Bacteria makes blue jeans green

GMT 10:03 2017 Friday ,15 December

US void hard to miss at Paris climate summit

GMT 09:39 2017 Thursday ,14 December

Investors turn against fossil fuels

GMT 09:44 2017 Tuesday ,12 December

The greening of international finance
Themuslimchronicle, themuslimchronicle
Themuslimchronicle, themuslimchronicle

Name *

E-mail *

Comment Title*

Comment *

: Characters Left

Mandatory *

Terms of use

Publishing Terms: Not to offend the author, or to persons or sanctities or attacking religions or divine self. And stay away from sectarian and racial incitement and insults.

I agree with the Terms of Use

Security Code*

mammals gave up night life only mammals gave up night life only

 



Themuslimchronicle, themuslimchronicle

GMT 09:23 2017 Wednesday ,19 April

1105 food baskets distributed in Yemen

GMT 09:35 2018 Monday ,08 January

Trump marijuana policy reversal stokes fears

GMT 11:09 2017 Saturday ,16 December

Russia poses risk to undersea cables: UK defense chief

GMT 09:56 2017 Thursday ,02 November

Digital subscriber gains rev up NY Times profit

GMT 01:38 2016 Thursday ,29 December

Iraqi President meets Kuwaiti Foreign Minister

GMT 17:37 2017 Tuesday ,21 February

Le Pen refuses to wear veil, fails to meet with Mufti

GMT 01:48 2016 Monday ,13 June

Pioneering solar pilots 'make sci-fi a reality'

GMT 18:45 2016 Wednesday ,21 December

Several Qaeda militants killed in drone strike

GMT 07:28 2018 Thursday ,11 January

As US freezes aid, Pakistan dismisses economic fears

GMT 11:14 2017 Sunday ,12 March

My video is flagrant but smashed the charts

GMT 09:21 2018 Wednesday ,10 January

unveils London boutique and appoints MG Empower

GMT 07:48 2018 Thursday ,04 January

L’Oréal Professionnel unveils Alexa

GMT 07:41 2017 Saturday ,19 August

Brief tourism impact from Spain attacks

GMT 00:02 2017 Friday ,22 December

UK-Iranian prisoner could be released

GMT 21:53 2016 Tuesday ,14 June

Israeli tech second only to Silicon Valley

GMT 00:25 2017 Friday ,27 October

Ex-HSBC executive can face US extradition: UK court

GMT 07:44 2017 Wednesday ,20 September

Iran asks award-winning film-maker to report to prosecutor

GMT 10:34 2017 Saturday ,11 November

Politics free? Even country music awards poke Trump

GMT 07:59 2017 Sunday ,17 December

Embassy in London marks Accession, National Days
Themuslimchronicle, themuslimchronicle
Themuslimchronicle, themuslimchronicle
 
 Themuslimchronicle Facebook,themuslimchronicle facebook  Themuslimchronicle Twitter,themuslimchronicle twitter Themuslimchronicle Rss,themuslimchronicle rss  Themuslimchronicle Youtube,themuslimchronicle youtube  Themuslimchronicle Youtube,themuslimchronicle youtube

Maintained and developed by Arabs Today Group SAL.
All rights reserved to Arab Today Media Group 2023 ©

Maintained and developed by Arabs Today Group SAL.
All rights reserved to Arab Today Media Group 2023 ©

muslimchronicle muslimchronicle muslimchronicle muslimchronicle
themuslimchronicle themuslimchronicle themuslimchronicle
themuslimchronicle
بناية النخيل - رأس النبع _ خلف السفارة الفرنسية _بيروت - لبنان
themuslimchronicle, themuslimchronicle, themuslimchronicle