Today in Science: Ultramarathoners can burn an astounding 11,000 calories per day

A daily read for all who love science, discovery, and insight ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­

SPONSORED BY

October 21, 2025—Octopuses also fall for the "rubber hand" illusion, a retinal implant restores reading in people with blindness, and fundamental limits to human metabolism.   —Andrea Gawrylewski, Chief Newsletter Editor TODAY'S NEWS An electrical device implanted under the retina helps to restore some visual acuity to people with age-related macular degeneration. Science Corporation An electronic retinal implant allows people with age-related macular degeneration to read again—but it isn't a full restoration, and it didn't improve participants' quality of life. | 4 min read  Individuals participating in the "No Kings" protests over the weekend were "radically less supportive of political violence" than those previously surveyed, according to sociologists polling protesters this year. | 2 min read   Different storytelling techniques can change how information is stored and retrieved in the brain of the listener. | 4 min read Is there a fundamental limit to human metabolism? A new study finds that even elite endurance athletes like ultramarathoners run up against a hard metabolic ceiling. | 3 min read Controversial evidence hints that complex life might have emerged hundreds of millions of years earlier than previously thought—and possibly more than once. | 17 min read More News Support science journalism you can trust with a subscription to Scientific American. Today in Science readers get special deals.  TOP STORIES An octopus ready for "rubber arm" testing. Sumire Kawashima Octopus Illusion Octopus brains can be tricked like human brains. In a recent experiment, octopuses fell for an adapted version of the "rubber hand" illusion. Scientists placed a fake rubber tentacle next to them and hid their real arm behind a partition. The researchers stroked both arms with tweezers, then after a few seconds, only stimulated the fake arm. The octopuses reacted with defense responses as if their real arm was being poked—with escape maneuvers and body color changes.   Why this is interesting: Before this study, only some mammals, including humans and mice, were known to be susceptible to this illusion. The study offers evidence that octopuses are "self-conscious" or aware of their bodies, says Kristin Andrews, a philosopher at York University in Toronto, who studies animal minds.   What the experts say: "We can't assume that octopuses have the same intuitive belief in a separation between a core self and the body that humans seem to have," Andrews says. "[They] might see the world in a very different way." —Andrea Tamayo, Newsletter Writer

SPONSORED CONTENT BY YAKULT Yakult: Pioneering Global Wellness  For 90 years, Yakult has been at the forefront of scientific research, focusing on gut microbiota, probiotics, and immunity to enhance human health. Through its innovative development of food and cosmetics, Yakult promotes global wellness, offering probiotic-based solutions in 40 countries and regions worldwide.   Learn More

FROM THE ARCHIVE Scientific American, Vol. 233, No. 4; October 1975

From the October 1975 issue of Scientific American:  Advent of Tomography: "Medicine is making the internal structures of the body far more accessible by noninvasive procedures. One, called reconstruction from projections, is coming into service. A tomogram is made by having an X-ray source move around a person in one direction, and film in the other direction, and mathematically combining X-ray images made from numerous angles into an image in three dimensions of organs within the body." EXPERT PERSPECTIVES The view of nature and animals only in terms of the economic services they provide to humans has been coined the "Capitalocene," and it reduces nature to a monetizable commodity. This oversimplified way of thinking ignores the complexity of nature and ecosystems, write Chirag Dhara and Vandana Singh, environmental scientists at Krea University, India, and Framingham State University, respectively. "The essential task today is to internalize this truth and to realign our values and the economy with it, before we irreversibly push Earth into a state less congenial to life," they say. | 5 min read PUZZLER Try to unscramble this image of our cover from April 1955. This cover shows tiny flowers—the largest is nickel-sized—that grow in the California desert and flower simultaneously in April as the days get longer.  More Puzzles Tonight will be a great night for stargazing. The rare Comet Lemmon will make its closest approach to Earth this evening. Look for it west of the arm of the big dipper, about an hour after sunset. By coincidence, the Orionid meteor shower also peaks tonight so lookout for shooting stars as well. Today is the new moon, so the sky will be darker and make it easier to spot cosmic objects. Enjoy and let me know what you see. Reach me: newsletters@sciam.com. Thanks for reading.   —Andrea Gawrylewski, Chief Newsletter Editor

Subscribe to this and all of our newsletters here. Scientific American One New York Plaza, New York, NY, 10004 ​ Support our mission, subscribe to Scientific American here ​ Unsubscribe    Preferences     View in Browser