Divers excavating an underwater collapse Mexico have found the bones of large meat eaters that lived there over the past ice age, a brand new examine reported.
The discovering is exceptional, as a result of few historic animal stays survive in Mexico’s scorching, tropical local weather. However these historic beasts, the short-faced bear (Arctotherium wingei) and the wolf-like Protocyon troglodytes, fell to their deaths in a deep cave, which was flooded quickly after. Consequently, their bones had been preserved in pristine situation, the researchers mentioned.
Each of those species had been removed from what scientists had thought of the animals’ houses. Beforehand, the creatures had been identified solely from South America. This discovering exhibits that in addition they lived a lot farther north, or greater than 1,200 miles (2,000 kilometers) away from their identified habitat, in regards to the distance from Boston to Miami. [Photos: These Animals Used to Be Giant]
Divers discovered the animal bones in Hoyo Negro, a totally submerged pit contained in the Sac Actun cave system within the japanese Yucatán Peninsula. Hoyo Negro is known for its anicent human stays; in 2007, divers discovered the cranium and bones of a teenage woman who lived about 12,000 to 13,000 years in the past.
The woman’s bones, in addition to these of the animals — together with tapirs, saber-toothed cats, cougars, elephant kinfolk referred to as gomphotheres, bears and canids — had been properly preserved. That is as a result of rising sea ranges on the finish of the final ice age flooded the caves, turning them right into a low-oxygen surroundings that was favorable for bone preservation, mentioned examine lead paleontologist Blaine Schubert, govt director on the Heart of Excellence in Paleontology at East Tennessee State College.
Nevertheless, as a result of a lot of the eye paid to Hoyo Negro’s bones centered on the teenage woman’s stays, a few of the animals had been misidentified, Schubert mentioned. Beforehand, the bear was mistakenly positioned within the genus Tremarctos and the wolf-like species was regarded as the coyote Canis latrans. The brand new examine units the document straight, Schubert mentioned.
Because the preliminary excavation, divers have discovered much more bones. Researchers now have the bones of 1, presumably two people of the canid and at the least seven of the short-faced bear, which date to the late Pleistocene, about 11,300 years in the past.
“The entire earlier document of this explicit kind of bear is simply identified from a number of localities in South America, and people are fragmentary stays,” Schubert informed Stay Science. “So, we went from not having any of the sort of bear exterior of South America to now having the most effective document of the sort of bear from the Yucatán of Mexico.”
Exploring north and south
The invention additionally sheds mild on the Nice American Biotic Interchange (GABI), which came about when North America related to South America and animals from every area crossed over into new lands. Most scientists suppose that this connection occurred about 2.5 million to three million years in the past, Schubert mentioned.
Throughout considered one of these early crossovers, the North American short-faced bear traveled right down to South America, as did the wolf-like canid. These ancestors then advanced into the brand new species that had been discovered within the cave, which, till now, scientists had by no means seen exterior of South America.
So, how did A. wingei and the wolf-like creature find yourself in Mexico? One concept is that they had been capable of recross that land bridge from South America into North America at a later time, Schubert mentioned. Nevertheless, it is also attainable that when the bear and canid had been coming right down to South America, a few of them stayed in Mexico, the researchers famous. [10 Extinct Giants That Once Roamed North America]
Just one dwelling relative of the short-faced bear presently lives in South America: the spectacled bear (Tremarctos ornatus). This bear has by no means been discovered exterior of South America. The brand new proof means that’s as a result of A. wingei was blocking its means, possible taking on the identical habitat and consuming the identical meals that the spectacled bear wanted to outlive, Schubert mentioned. “Maybe they created a barrier,” he mentioned.
The researchers did a formidable job of appropriately figuring out the bear and canid species, mentioned Ross MacPhee, curator of mammalogy and vertebrate zoology on the American Museum of Pure Historical past in New York Metropolis, who was not concerned within the examine.
The examine highlights how helpful these underwater websites are, particularly within the scorching, moist tropics the place historic bones normally degrade, Ross informed Stay Science. “You may get a probe into the previous that you do not ordinarily count on to get, and that is the beauty of these caves within the Yucatán.”
The examine was printed on-line yesterday (Could 1) within the journal Biology Letters.
Initially printed on Stay Science.