Sharks almost dissappeared, like dinosaurs -new extinction event discovered

[FfFfFfFF 58,058]

Sharks are some of nature’s greatest survivors. For more than 400 million years, the marine predators have plied Earth’s waters, from shallow reefs to the heart of the open ocean. Sharks are older than the oldest fossil forest. They’ve made it through at least four mass extinctions.

And yet, 19 million years ago, something mysteriously dealt open-ocean sharks a huge blow—one from which they’ve never recovered.

Records of this extinction, detailed for the first time in the journal Science, come in the form of shark scales, called denticles, found in seafloor samples from the Pacific Ocean. Based on the shapes and abundance of denticles in the samples, the researchers estimate that the planet’s open-ocean shark populations suddenly and inexplicably fell by more than 90 percent. By contrast, during the extinction event that killed off the non-avian dinosaurs 66 million years ago, sharks suffered losses of roughly 30 percent.

“The sharks are screaming, Something really big happened here,” says lead study author Elizabeth Sibert, a paleobiologist and oceanographer at Yale University. “Sharks have a 400-million-year evolutionary history; they’ve been around a long time; they’ve seen a lot. And there’s something that could knock out 90 percent of them?”

Nobody knows what triggered the extinction, but whatever occurred, it must have happened in roughly 100,000 years, the geological blink of an eye. Bizarrely, the extinction doesn’t align with any known major shift in Earth’s climate or any major evolutionary change among other open-ocean predators.

That said, the decline in sharks may have given other marine animals their chance to shine. Several million years after the extinction, groups including tuna, seabirds, whales, and migratory sharks diversified, locking in the kind of open-ocean ecosystem we see today.

 

 

Right - Smooth (#62 and #63) and linear (all others) denticle types described in the study. Those marked with a (†) are extinct. Most modern sharks have linear denticles.Credit...E. Sibert and L. Rubin, Science 2021

Left - Geometric denticle types, with extinct types also marked with a (†). Extant geometric denticles are found mostly on smaller ambush-style predators that live in the deep sea.Credit...E. Sibert and L. Rubin, Science 2021

 

Source: https://www.nationalgeographic.com/science/article/mystery-event-caused-shark-populations-to-crash-19-million-years-ago?, https://www.nytimes.com/2021/06/03/science/sharks-extinction-oceans.html

[Mother of Puppies 36,615]

I ****ing LOVE sharks... why do people hate them? They are one of the most fascinating wild animals out there...

[MyQueen 2,409]

 

Why predators.... Its nature! 

[FfFfFfFF 58,058]

3 minutes ago, MotherOfPuppies said:

I ****ing LOVE sharks... why do people hate them? They are one of the most fascinating wild animals out there...

Katz Perrys Superbowl damaged their reputation.

 

[MyQueen 2,409]

5 minutes ago, MotherOfPuppies said:

I ****ing LOVE sharks... why do people hate them? They are one of the most fascinating wild animals out there...

They are demonised like snakes, spiders.....fear

[Mother of Puppies 36,615]

15 minutes ago, MyQueen said:

They are demonised like snakes, spiders.....fear

well... I'm very scared of them too... I'd ****ing **** my pants if I ever saw one while I'm snorkeling

[TasteLikeWhiskey 1,561]

I have had the experience of cage-diving with great whites. It is fuccccking terrifying.

It is an amazing species. But it is really not hard to understand why they are (irresponsibly) demonized. Their eyes are so dead, yet focused

[huttont 6,001]

Ugh I love your threads @FfFfFfFF this is fascinating