Ancient Deer-Like Creatures Returned to the Ocean to Become Whales. But Why?

[eppur_se_muova]

Friday, March 23, 2018

During the Early Triassic period (approx. 252-247 million years ago) onward, dozens of terrestrial and freshwater animals returned to the sea. Birds, reptiles, amphibians, and mammals were among them. They evolved and eventually became dominant players in their ecosystems during the Mesozoic and Cenozoic eras. Today, lots of the marine mammals we know and love started out as land-based species.

For instance, a walrus’s ancestor resembles the modern otter, while whales come from a species of ancient deer-like creatures known as Indohyus. They roamed southern Asia about 48 million years ago. An Indohyus was only about the size of a raccoon, and researchers believe that they fed on aquatic plants.

So what coaxed these creatures back into the ocean 100 million years after their ancestors climbed out of it? A duo of researchers contend that this question has received far too little attention, until now. The results of their study has been published in a report in the journal Paleobiology. To date, there have been two prevailing hypotheses.
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Vermeij and Motani’s study supports the idea that terrestrial animals took advantage of food sources in the ocean periodically, not just after mass extinctions, and the trend has only increased over the past 60 million years or so. One reason that may be a pull factor: kelp and seagrass beds developed over this period, allowing for more marine life to sprout and proliferate closer to shore.

To learn more about whale evolution, click here.



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more: https://paleontologyworld.com/exploring-prehistoric-life-paleontologists-q/ancient-deer-creatures-returned-ocean-become-whales-why

[WhiteTara]

1. They saw the future on land

and said, hell no.

[eppur_se_muova]

2. ...

[exboyfil]

3. Turtles

Ocean, land, ocean, and back to land. They just can't make up their minds.

[Canoe52]

4. I used to live on land, but now live on the sea...of course I have a boat...

[Permanut]

5. Wish I coulda been there to see this..

Totally cool, thanks for posting, eppur. Seems that at times, life evolved to fill a niche in the environment just because it was there.

[Botany]

6. Deer are always getting hit by cars on land

https://upload.wikimedia.org/wikipedia/commons/4/45/Japan_road_sign_214-2.svg

[muriel_volestrangler]

7. "... no one should ever have left the oceans."

Orbiting this, at a distance of roughly ninety million miles is an utterly insignificant little blue-green planet, whose ape descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea. This planet has, or had, a problem, which was this. Most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movements of small, green pieces of paper, which is odd, because on the whole, it wasn't the small, green pieces of paper which were unhappy.

And so the problem remained, and lots of the people were mean, and most of them were miserable, even the ones with digital watches.

Many were increasingly of the opinion that they'd all made a big mistake coming down from the trees in the first place, and some said that even the trees had been a bad move, and that no-one should ever have left the oceans.

And then one day, nearly two thousand years after one man had been nailed to a tree for saying how great it would be to be nice to people for a change, a girl, sitting on her own in a small cafe in Rickmansworth suddenly realised what it was that had been going wrong all this time and she finally knew how the world could be made a good and happy place. This time it was right, it would work, and no-one would have to get nailed to anything.

The Hitch-Hikers Guide to the Galaxy prologue