If it's not,then why so many rays living in it.As far as i know,stingrays only live in the ocean.Could it be that the rays ancestors were once a sea dweller millions of years ago and succesfully evolve into a fresh water creature when there's a sudden geological changes to the ocean floor?
2006-10-18 19:09:27 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
The Rio Pantanel drains into the Atlantic. So, rays could have evolved to become more fresh water tolerant and gradually moved into the environments upriver. The process would not necessarily have required a sudden geologic change, but you are probably on the right track about the ancestors of the freshwater rays having been ocean dwellers.
However, I discovered an article that at least one scientist believes that a high sea level during the Miocene resulted in "left behinds" that evolved into fresh water rays, so perhaps you are correct.
2006-10-19 04:18:09 · answer #1 · answered by luka d 5 · 0⤊ 0⤋
Everywhere was once the ocean floor.
2006-10-18 20:27:21 · answer #2 · answered by S h ä r k G û m b ò 6 · 0⤊ 0⤋