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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: I Can Feel Your Heartbeat ... Stop
17 January 2012 7:01 pm
The heart wants what the heart wants, and boa constrictors want the hearts in their prey to stop beating. New research reveals that the snakes stop squeezing when they sense their prey's heart stop. In the study, scientists inserted a tiny, water-filled bulb next to the hearts of dead rats, and pumped water in and out of it to mimic heartbeats. The researchers also warmed the rodents to their living body temperature of 38°C. Then they let the snakes at them. Although wild-caught boas squeezed harder than captive-bred snakes, both stopped constricting shortly after the fake rat heart stopped beating, the team reports online today in Biology Letters. The authors speculated that boas evolved their sensitivity to heartbeats early on, when they went after cold-blooded animals that could survive for hours on little oxygen; just because their prey stopped struggling didn't necessarily mean they were dead. Constriction requires an enormous amount of energy—seven times what the snake spends while resting—so once an animal is deceased, the reptiles can save their strength for eating it.
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