![]() ![]() Mean temperatures may have hovered in the mid- to high-80s Fahrenheit or higher. The trees had wider leaves, indicating greater precipitation-more than 150 inches of rain per year, compared with 80 inches for the Amazon now. We have it all, and you can’t find it anywhere else in the tropics.”įifty-eight million years ago, a few million years after the fall of the dinosaurs, Cerrejón was an immense, swampy jungle where everything was hotter, wetter and bigger than it is today. “Cerrejón is the best, and probably the only, window on a complete ancient tropical ecosystem anywhere in the world,” said Carlos Jaramillo, a paleontologist at the Smithsonian Tropical Research Institute. The multinational corporation that runs the mine, Carbones del Cerrejón Limited, extracted 31.5 million tons of coal last year alone.Ĭerrejón also happens to be one of the world’s richest, most important fossil deposits, providing scientists with a unique snapshot of the geological moment when the dinosaurs had just disappeared and a new environment was emerging. It is one of the world’s largest coal operations, covering an area larger than Washington, D.C. Without this breathing adaptation, they say, snakes may not have become such a diverse class of reptiles spread out across the globe.In the lowland tropics of northern Colombia, 60 miles from the Caribbean coast, Cerrejón is an empty, forbidding, seemingly endless horizon of dusty outback, stripped of vegetation and crisscrossed with dirt roads that lead to enormous pits 15 miles in circumference. The team believes that this ability to modulate rib engagement emerged while or before snakes evolved the ability to constrict, and perhaps ahead of a snake’s ability to eat large prey. Capano, who added that as soon as the cuff was removed, the ribs used to breathe during rest immediately re-engaged. “The snake just turns off a section of the rib cage and then turns on another section,” said Dr. ![]() But when the blood pressure cuff was wrapped around those ribs, a specific set of ribs further down the snake’s body began expanding to draw in air. When resting, boa constrictors breathe using ribs near the upper third of their lungs. Then they filmed these regions with X-ray video and, using a blood pressure cuff, restricted rib motion in specific regions, simulating what happens in nature when these snakes constrict their prey. With the snakes anesthetized, the team implanted metal markers no bigger than half a millimeter in the ribs and vertebrae they wanted to image. To test these hypotheses, the research group visualized a boa constrictor’s rib cage during constriction using 3-D X-ray technology. But another option would be that they use any uncompressed area of their rib cage to draw air into their lungs. Brainerd said.īased on previous observations in the field, scientists had theorized that, when constricting and ingesting prey, snakes are most likely changing the specific region of their rib cage that’s expanding. “Something had to happen with the evolution of their lung ventilation system in order for them to become these elongated, small-headed animals that eat big meals,” Dr. Exactly how boas could breathe while constricting or ingesting remained a mystery. Ingesting prey also expands ribs to their limit. While they’re squeezing, those ribs are compressed. “Large prey ingestion really opened up all these new avenues for snakes to evolve that otherwise would not have been possible,” said John Capano, an evolutionary biologist at Brown University and an author of the study. Their findings shed light on the anatomy of snakes and how these slithering predators have come to thrive in so many parts of the world. ![]() Their work was published on Thursday in the Journal of Experimental Biology. ![]() Brainerd and her colleagues set out to understand how boa constrictors breathe under such cramped conditions and discovered that they’re able to precisely shift the region of their rib cage that expands to draw air into their lungs. “And that takes quite a bit of energy, so they have to be breathing.”ĭr. “They do this for 10, 15, up to 45 minutes,” said Elizabeth Brainerd, an evolutionary biologist at Brown University. Some of their larger relatives, anacondas, can eat capybara and deer, and there have been some instances of pythons eating people.īut constricting and ingesting prey is no small - or quick - feat. To kill its prey, a boa will coil around it, squeezing hard enough to stop the prey’s blood from flowing, and then, stretching its jaws open, devour it whole. The boa constrictor got its name for a reason. ![]()
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