Alligators Regrow Tails After Amputation, New Study Finds

American alligators fight near launch pad 39A at Kennedy Space Center in Cape Canaveral, Florida June 7, 2007. REUTERS/Charles W. Luzier (UNITED STATES) - RTR1QK2L (REUTERS/Charles W. Luzier)
American alligators fight near launch pad 39A at Kennedy Space Center in Cape Canaveral, Florida June 7, 2007. REUTERS/Charles W. Luzier (UNITED STATES) - RTR1QK2L (REUTERS/Charles W. Luzier)
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Alligators Regrow Tails After Amputation, New Study Finds

American alligators fight near launch pad 39A at Kennedy Space Center in Cape Canaveral, Florida June 7, 2007. REUTERS/Charles W. Luzier (UNITED STATES) - RTR1QK2L (REUTERS/Charles W. Luzier)
American alligators fight near launch pad 39A at Kennedy Space Center in Cape Canaveral, Florida June 7, 2007. REUTERS/Charles W. Luzier (UNITED STATES) - RTR1QK2L (REUTERS/Charles W. Luzier)

Cornered by a dangerous predator, a gecko can self-amputate its still twitching tail, creating a fleeting moment of distraction - a chance for the lizard to flee with its life.

Small reptiles such as geckos and skinks are well known for this remarkable ability to sacrifice their tails. Now, scientists discovered that much larger alligators can regrow theirs too, but only while they're young.

Researchers from the University of Arizona found that Juvenile American alligators (Alligator mississippiensis) can regrow up to 18 percent of their total body length back (about 23 cm or 9 inches of length). By imaging and dissecting the tail regrowth, researchers found alligators do this quite differently from the other animals we know that can regenerate their appendages. The study was published in the latest issue of the journal Scientific Reports.

While other animals self-amputate themselves, small geckos often lose their tails due to injuries caused by dangerous predators or hunting attempts by humans. In addition to difference in amputation conditions, the researchers observed differences in the mechanism and timing of regrowth.

"If injured, reptiles can reform a segmented skeleton, complete with muscles, while the regrown alligator tail is supported by an unsegmented cartilage tube rather than bone," ASU cellular biologist and first author of the research Cindy Xu said in a report published Saturday on the Science Alert website.

"It also may take them considerably longer to regrow their missing bits. While skinks can do it in as little as six months, a related crocodilian takes up to 18 months to reform their tails," she explained.

The researchers reached these conclusions by studying the final regrowth results of American alligators. But given that they are a threatened species, further studies on how this process works may be challenging, but could provide some useful information.

"If we understand how different animals are able to repair and regenerate tissues, this knowledge can then be leveraged to develop medical therapies," said ASU anatomist and co-author Rebecca Fisher.



Eastern Half of US Braces for More Long Days of Dangerous Heat

A kid cools off in Crown Fountain in Millennium Park as temperatures climbed to over 95 degrees Fahrenheit (35 degrees Celsius), in Chicago, Illinois, on June 21, 2025. (Photo by KAMIL KRZACZYNSKI / AFP)
A kid cools off in Crown Fountain in Millennium Park as temperatures climbed to over 95 degrees Fahrenheit (35 degrees Celsius), in Chicago, Illinois, on June 21, 2025. (Photo by KAMIL KRZACZYNSKI / AFP)
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Eastern Half of US Braces for More Long Days of Dangerous Heat

A kid cools off in Crown Fountain in Millennium Park as temperatures climbed to over 95 degrees Fahrenheit (35 degrees Celsius), in Chicago, Illinois, on June 21, 2025. (Photo by KAMIL KRZACZYNSKI / AFP)
A kid cools off in Crown Fountain in Millennium Park as temperatures climbed to over 95 degrees Fahrenheit (35 degrees Celsius), in Chicago, Illinois, on June 21, 2025. (Photo by KAMIL KRZACZYNSKI / AFP)

Tens of millions of people across the Midwest and East braced Sunday for another sweltering day of dangerously hot temperatures as a rare June heat wave continued to grip parts of the US.

Most of the northeastern quadrant of the country from Minnesota to Maine was under some type of heat advisory Sunday. So were parts of Arkansas, Tennessee, Louisiana and Mississippi, The Associated Press reported.

The temperature had already reached 80 degrees Fahrenheit (26.6 degrees Celsius) in the Chicago area by 7:30 a.m. Sunday, according to the National Weather Service. Forecasts called for heat indices of between 100 and 105 degrees F (37.7 to 40.5 degrees C).

The heat index in Pittsburgh was expected to top 105 F. The temperature in Columbus, Ohio, was 77 F (25 C) at 8:30 a.m. Highs there were expected to reach 97 F (36 C) with a heat index around 104 F (40 C).

Forecasts called for a heat index of 100 F in Philadelphia on Sunday, with a 108 F (42.2 C) heat index on Monday.

The city’s public health department declared a heat emergency starting at noon Sunday and ending Wednesday evening. Officials directed residents to air-conditioned libraries, community centers and other locations, and set up a “heat line” staffed by medical professionals to discuss conditions and illnesses made worse by the heat. At Lincoln Financial Field, officials said each fan attending Sunday’s FIFA World Cup match would be allowed to bring in one 20-ounce (0.6-liter) plastic bottle of water.

Sunday marked the second straight day of extreme heat across the Midwest and East Coast. Heat indices on Saturday hit 103 F (39.4 C) in Chicago and 101 F (38.3 C) in Madison, Wisconsin, turning that city's annual naked bike ride into a sticky and sweaty affair.

Minneapolis baked under a heat index of 106 F (41.1 C). The actual temperature was 96 degrees F (35.5 degrees C), which broke the old record for the date of 95 F (35 C) set in 1910, according to the weather service.

The heat is expected to persist into the coming week, with the hottest temperatures shifting eastward. New York City is expected to see highs around 95 F (35 C) on Monday and Tuesday. Boston is on track for highs approaching 100 F (37.7 C) on Tuesday, and temperatures in Washington, D.C., were expected to hit 100 F on Tuesday and Wednesday.

Meteorologists say a phenomenon known as a heat dome, a large area of high pressure in the upper atmosphere that traps heat and humidity, is responsible for the extreme temperatures.

Mark Gehring, a National Weather Service meteorologist in Sullivan, Wisconsin, said this level of heat is not uncommon during the summer months in the US, although it usually takes hold in mid-July or early August. The most unusual facet of this heat wave is the sheer amount of territory sweltering under it, he said.

“It's basically everywhere east of the Rockies,” he said, referring to the Rocky Mountains. “That is unusual, to have this massive area of high dewpoints and heat.”