The birth of the Gulf of California, which rifted from Mexico and created the Baja Peninsula 6 million to 8 million years ago, was accelerated by the formation of a double subduction zone more than 6,000 miles (9,600 kilometers) away, near Japan. This reorganization led to a transfer of tectonic force across the Pacific tectonic plate, which, in turn, opened the Gulf of California and ultimately led to the Grand Canyon's formation, according to new research published Oct. 29 in the journal Science.
The findings will help researchers understand more about plate boundaries, which is where most of the strongest earthquakes on the planet originate.
"It's more than a regional curiosity," study co-author Thorsten Becker, a geophysicist at the University of Texas at Austin (UT Austin), told Live Science. "It's a reminder of the global connectedness of mantle convection and plate tectonics."
The Gulf of California is an example of a rift zone, a place where continental crust pulls apart and creates a spot so low that it can be filled by ocean water. There are many rift zones around the world; a currently active one is the Red Sea. But rifting can slow down, speed up or peter out entirely. In the Gulf of California, rifting not only persisted, but sped up. Rifting took about 6 million to 13 million years — much quicker than the typical speed of 30 million to 80 million years.
Study co-author Guido Gianni, a geophysicist at the Czech Academy of Sciences, wondered why that was. No previous research fully explained the rapid rifting, which changed the face of North America in many ways. Not only did the rifting transfer Baja California to the Pacific Plate, but it provided an outlet for the developing Colorado River, which subsequently carved the Grand Canyon on its way to sea level.
Gianni and Becker's doctoral student at UT Austin, Xiang He, used a global model of plate tectonics, run on supercomputers at the Texas Advanced Computing Center on campus, to find out if far-flung forces might provide an explanation. Around the same time the Gulf of California was pulling apart, Japan was undergoing its own geological changes. Off the coast of Japan, the Pacific Plate subducts, or pushes under, the Eurasian Plate. About 10 million to 12 million years ago, a single subduction zone near Japan transitioned into two separate subduction zones.
A double subduction zone off Japan (left inset) accelerated the growth of the Gulf of California (right inset). (Image credit: He et al.)This transition at the western end of the Pacific Plate influenced the tectonic forces on the other side of the plate, He, Gianni, Becker and their colleagues found.
"It turned out — ta-da! — [with] the change in this pulling stress, Baja California was one of the few places outside the Japan region that were affected," Becker said. It was "unexpected and sort of a little bit too good to be true."
The researchers tweaked their model to see if the result held with different assumptions about stresses and mantle properties, and it did.
influenced the tectonic forces on the other side of the plate, He, Gianni, Becker and their colleagues found.
"It turned out — ta-da! — [with] the change in this pulling stress, Baja California was one of the few places outside the Japan region that were affected," Becker said. It was "unexpected and sort of a little bit too good to be true."
The researchers tweaked their model to see if the result held with different assumptions about stresses and mantle properties, and it did.
The Gulf of California was already rifting regardless of the situation across the Pacific. The initial rift was caused by the subduction of a tectonic plate called the Farallon Plate, located under the West Coast of North America. The Farallon slab stretched and thinned the continental crust of the North American plate as it moved. But such rifting might have ended with nothing more than the formation of a little valley or low spot if Japan's influence had not kicked in to give the rifting some extra oomph.
The findings have a direct effect on scientists' understanding of how plate boundaries form, Becker said. And this isn't just academic. The findings could have implications for understanding earthquake-generating faults such as the San Andreas in California and the Cascadia subduction zone in the Pacific Northwest, Becker said. Cascadia is what's known as a "megathrust" boundary, capable of triggering quakes of more than magnitude 9.
"If I'm asking what is the mantle doing underneath Cascadia so I get our megathrust correct," Becker said, "I need to include these effects."
'> Tectonic forces near Japan helped fuel the formation of the Grand Canyon Skin carries sensors to detect heat and cold that influence each organism's decision to stay in or move out of an environment. The new study, published Oct. 28 in the Journal of Physiology, found that these sensors activate at higher temperatures in female mice, which appears to shift their preferred temperature roughly 7 degrees Fahrenheit (4 degrees Celsius) higher than that of male mice. Testosterone seems to influence this difference in activation.
"You could say it's just a cute observation of no particular importance," said study co-author Peter McNaughton, a pharmacologist at King's College London who studies pain, thermal sensation and thermoregulation. "[But] it's got practical ramifications," in that it might be important in designing buildings and spaces that accommodate people, he told Live Science.
A distinct temperature preference
Proteins in the skin's nerve endings activate in response to warmth or cold. "You can look at them like little electrical generators in the nerve endings," said Dr. Michael Caterina, a neuroscientist at Johns Hopkins University who was not involved in the research.
When activated, these proteins allow charged ions to enter sensory nerve cells, which, in turn, transmit electrical signals to the brain. The circuits a given nerve cell connects to determines our perception of heat or cold, Caterina told Live Science.
Beyond humans, it is known that many female animals, including mice and birds, prefer slightly warmer temperatures than their male counterparts do. So the researchers set up an experiment to investigate these differences.
They put 30 male and 27 female mice on two adjacent plates of different temperatures — one at 91.4 degrees Fahrenheit (33 degrees Celsius) and another that varied between lower and higher temperatures. A camera tracked the mice's movements and calculated how much time they spent on each plate.
Both male and female mice spent more time at the 91.4 F plate when the second plate was cooler. However, when put next to a plate measuring 100.4 F (38 C), female mice spent significantly more time on the warmer plate than male mice did. The average preferred surface temperature was approximately 89.6 F (32 C) for male mice and 96.8 F (36 C) for female mice.
"Since the top of the cage was completely open, there was no question of the air temperature affecting the mice," McNaughton said, so the preference was driven solely by the sensors in their skin. The researchers also measured the internal and skin temperatures of the mice and confirmed that there were no significant differences between the sexes on those fronts.
The role of testosterone
The scientists explored what would happen if they genetically deleted the warmth-detector protein. In male mice, this reduced their avoidance of the warmer plate, suggesting this protein normally sends a signal that discourages them from staying on warmer surfaces. The mice's preferred temperature also rose to about 95 F (35 C), closer to that of females.
The study suggests that testosterone somehow tweaks the function of heat-sensing nerves in the skin. (Image credit: Alllex via Getty Images)In female mice, deleting or blocking the protein did not have any significant effect.
The team then tried eliminating or blocking the coolness-detecting protein, finding that males and females didn't avoid the cool plates as strongly as they did before. Female mice also spent less time on the warmer plates, but males' preference for the warmer plates didn't change.
"Females are a little bit more responsive to activation of the cold receptor," Caterina said, "and a little bit less responsive to activation of the warmer receptor." That's despite the temperature-sensing neurons in both sets of mice working identically, the team found.
The researchers suspected that sex hormones might help to explain this difference.
They gave a group of male mice a drug that blocks the production of testosterone. Weeks after the treatment, these mice spent more time on the 38 C plate than males with normal testosterone. Meanwhile, female mice given testosterone lost their preference for warmer temperatures.
Interestingly, giving male mice female hormones, including forms of estrogen and progesterone, did not affect their temperature preferences. And blocking the hormones in female mice also had no effect. These hormones are known to influence other aspects of temperature regulation in the body, though, such as heat dissipation through the skin; but in this case, they didn't seem to affect animals' perception of temperature.
"So it really seems as though testosterone is the most important determinant," McNaughton said. But these changes were only partial; testosterone did not completely reverse the differences between the sexes. "So there is something else going on that we weren't able to identify," he added.
The exact mechanism for how testosterone impacts the sensor proteins is not clear. Because the effect happened over weeks, researchers suggested that it did not directly affect the temperature-sensing proteins. It might instead act indirectly by influencing the activity of genes, but further studies would be needed to confirm this idea.
Although the researchers did not conduct any tests in humans, McNaughton noted that the same sensor proteins are present in people and that studies with humans suggest that they behave in a similar way.
This research provides "valuable information" for understanding how the proteins responsible for sensing temperature work, Caterina said. Understanding these mechanisms could be useful for studying conditions like neuropathic pain, in which people's sensitivity to heat and cold is enhanced.
"What kinds of signals create our daily experiences around temperature is by itself very important," he told Live Science. "It's a big part of understanding ourselves as living beings."
This article is for informational purposes only and is not meant to offer medical advice.
'> Women often get cold more easily than men — a mouse study offers hints why That weekend, I started to feel a little sick, but nothing too bad. My mom kept giving me over-the-counter medicine and it would work for a bit, then once it wore off, it would get really bad. I'd planned to go to one of my friend's birthday parties then spend the night with my best friend. I went to the party, but I texted my mom saying I should come home because I really wasn't feeling well, which was not usual for me at all. That night I asked my mom to sleep with me because I just felt terrible.
That was Saturday. By Sunday night, the only position that I could get comfortable in was my mom holding me like a baby. My mom just held me all weekend. My whole body just hurt and I started feeling like I couldn't breathe properly. That got way worse Monday morning.
We were waiting for my pediatrician to open up and my mom suggested taking a shower, saying, "Maybe that will help you feel a bit better before we go to the doctor." She had to help me take a shower because I was so weak, I couldn't stand by myself. She stepped away for a second just to grab a towel and said that when she came back, my lips were turning gray and my eyes were starting to look sunken in. She knew that something was not right so she called my dad, who was at the grocery store, and told him to just leave everything, that we need to get to the hospital.
Allen was put on life support and had to be intubated for five weeks after getting sick with flu. (Image credit: Madi Allen)Our local hospital is just a small rural hospital — everybody gets transferred out. They diagnosed me with double pneumonia and then sent me to a different hospital 30 minutes away that specialized more in kids.
My dad rode with me in the ambulance while my mom went home and grabbed a few things — she thought we'd just be there for a few days. By the time we got to the second hospital, I was in respiratory distress. They wanted to intubate me straight away but were waiting until my mom got there so she could talk to me — my dad did the best he could, but my dad didn't know how to calm me down.
I don't think the doctors even told me that they were putting me to sleep. My mom had to be the one to tell me. I remember being very scared. They put this mask on my face for the BiPAP [bilevel positive airway pressure machine, which delivers pressurized air to a patient] and I felt like that was suffocating me. It didn't feel like it was helping at all, which, I guess, at that point, it wasn't. They were just trying everything they could. I was begging them to take it off of me, crying and just saying, "one minute, just take it off for one minute."
Finally my mom tried to calm me down and she's like, "They're gonna have to put you to sleep now." I remember her telling me, "You're just gonna go to sleep for like a couple of hours and then you're gonna wake up and you're gonna feel a lot better."
My mom had to leave the room while they were doing that. As she was walking out the door, the last thing I said was "Mom" and then I put my hands in a heart shape. That was the last thing I did and the last time my mom heard my voice for five weeks.
After I was intubated, things got worse. I had to be put on life support so needed to be moved to a bigger hospital in St. Louis, Missouri. The flight team came to evaluate me and they later told me they didn't think they were ever going to get me to Saint Louis. They thought I wasn't going to make the trip. But they said my mom was begging them to help me, everyone in my family was begging them, so they did everything they could to get me on the helicopter. They worked on me for several hours — every time they tried to move me something would go wrong — but eventually they got me there.
The doctors had to call my parents to get permission to do surgery and put me on life support. My mom said that every time she heard my dad's phone ring, she thought they were calling to tell them that I didn't make it. They were told twice that it was more than likely I was going to pass than make it. They were trying to prepare my parents that I wasn't going to make it.
After getting out of hospital, it took years for Allen to recover, eventually having part of her lung removed that had been badly damaged by the virus. (Image credit: Madi Allen)I woke up five weeks later, and it was very confusing. Everybody was told if I asked what day it was, just to tell me the day of the week. When someone accidentally told me the date, I started crying because my aunt was supposed to be getting married a few weeks later and I was worried about being at her wedding. My mom wasn't there, so my dad had to calm me down and then he told me the wedding had been pushed to October so I could be there.
The second thing I was worried about was that I was supposed to take a test on the Constitution and that I'd missed it. I ended up taking it in the hospital. I was there for 93 days. I got out the very last week of school, so I got to go in on the last day of school and surprise my classmates and my teachers.
That summer, I didn't really do anything besides go to doctor's appointments. I was doing physical therapy, occupational therapy and speech therapy — literally all my time was spent at the hospital in therapy. I'd missed three months of school, but I got to start eighth grade with all my friends, and I ended up playing basketball again. But the next several years was a lot of hard work of trying to get back to my normal.
It probably took the rest of junior high and high school to get back to how I would have been before. It was a very long process and during that time I got sick a lot, so I ended up back in the hospital several times. And it was hard going through that as a teenager — I felt like everybody else is living their normal life, and I felt like I missed out on a lot. Looking back now, I still feel like I did miss out a lot. But I think we made the best of the circumstances.
During COVID, when I was 22, I kept getting sick, and the doctors finally told me that part of my lung was so damaged from the flu it was causing infections, so they gave me an option of getting part of my lung removed. It was a major surgery, but I did it and that was probably the best decision I ever made, because it's been five years and I have not been in the hospital once.
I moved to Florida about three years ago, and I started working as a medical assistant in a pulmonary clinic. This semester I got accepted into respiratory therapy school, so for the next two years, I'm going to be in school for respiratory therapy. It's kind of a full circle moment, to come back into the medical field, because there was a point in my life where everybody was asking me, "Oh, do you want to be a doctor? Do you want to be a nurse?" And I'm like, "Absolutely not." I was still so sick that I was there all the time. I never wanted to be there.
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I went to college and I got a degree in criminal justice, but I never really knew what I wanted to do. I ended up getting a job at our local hospital — that first hospital that I went to. Every time they put me in the ER I just loved being there. That job made me realize that this is what I wanted to do.
When people hear my story, they don't realize that if I don't tell the end — after the hospital until now — they don't realize that my life didn't go back to normal after. It's taken 10 years. And it's hard. Some of the other family members that we've gotten to know through Families Fighting Flu, it's difficult listening to their stories. Sometimes I feel like I have this survivor's guilt. Their stories sound exactly like mine — but their kids didn't make it.
Before I got sick I got the flu shot every year, but that year we just got busy and it got put on the back burner. Since getting sick I have always made it a priority to get the flu shot every year. I know it is not a guarantee that I will never get the flu again — but hopefully it will reduce the chances of it ever getting that bad again.
With thanks to Families Fighting Flu, a non-profit organization that promotes flu vaccination and raises awareness of the severity of the infectious disease through families that have been affected.
Opinion on Live Science gives you insight on the most important issues in science that affect you and the world around you today, written by experts and leading scientists in their field.
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'> I almost died from flu. My life didn't go back to normal after. When a cat is petted in these areas, its body language often changes. "They might do a quick head turn, looking at your hand, or they might start moving away from you or wiggling around a lot, basically trying to get away from the petting," Mikel Delgado, a cat behaviorist and senior research scientist at Purdue University, told Live Science in an email. "If these early warning signs are ignored, they might escalate to biting, hissing or scratching."
But why do cats dislike it so much when humans touch these specific areas?
Although there has been little formal research into this question, animal behavior experts proposed a few ideas for why cats don't like to be touched in certain areas.
Off-limits petting zones
"Cats are prey animals as well as predators and so they can be very protective of areas that are particularly vulnerable to injury during attack, such as the belly area," Sarah Ellis, head of cat mental well-being and behavior at the cat welfare charity International Cat Care, told Live Science in an email.
A cat's belly houses vital organs — such as the liver, stomach and intestines — without the protective bony cage that the ribs provide for the heart and lungs. Although cats have evolved a special feature called the "primordial pouch" — basically a flap of loose skin and fat on their belly — which provides a little extra padding to protect vital organs during fights, most cats still feel threatened when humans touch or rub their belly.
Cats have extra padding on their stomachs to protect their organs. (Image credit: Cyndi Monaghan via Getty Images)Dogs have a similar anatomy to cats, but they have to worry less about falling prey to larger animals. Cats, meanwhile, can be hunted by dogs, urban coyotes, and even birds such as hawks and owls, making it natural for them to be protective of their bellies.
The tail is also a vulnerable area for cats. "When a cat is chased by another animal, including other cats, the tail is often the part of the cat's body that is closest to touch," Ellis said, "and the risk of being bitten at the base of the tail is high." Therefore, cats may be skittish about having their tail stroked.
When it comes to foot rubs, there are two possible explanations for why most cats hate them. First, a cat's paws are essential in threatening situations. Running away from danger is a cat's preferred survival strategy, and they rely on their paws as a means of escape, Ellis explained. If they can't run away, "a cat may resort to repelling any threats through swiping and scratching and it needs its paws free to do so," she said. "It is therefore predisposed to not enjoy having its paws restricted in any way."
Another reason could be that cats' paws are very sensitive. They have wrist whiskers (also known as "carpal vibrissae") and toe pads that are sensitive to various types of stimuli, like pressure and heat, Delgado said, "so it's not surprising that many cats are sensitive about having their feet touched."
Petting rules and exceptions
If you're interacting with a cat, it's generally a good idea to stick to the areas where most cats like to be petted: the base of their ears, around their cheeks and under their chin. These areas are rich in scent glands, and cats tend to rub them against other cats they are friends with, Delgado explained. So essentially, cats like being petted in those areas because "they treat us as they do other cats," Delgado said.
But some cats go against the grain. "I've had a few who enjoyed belly rubs," Delgado said. Others enjoy having their tail stroked briefly and show their pleasure "by pushing their rump into the hand of the petter and holding their tail up in the air," Ellis said. (This behavior is sometimes called "elevator butt.")
As puzzling as it may be to humans, these varied preferences are a reminder that "each cat is an individual," Delgado said. Positive responses to petting of the belly, feet or tail can also signal close bonding to a human, Ellis said.
She advises people to "always take the cat's lead, learn what each individual cat likes and dislikes and respect these preferences."
How much of a cat fan are you? Find out by taking our cat quiz!
'> Why do most cats hate it when you touch their belly, feet or tail? .
Interestingly enough, the comments reflect a slightly different trend. One reader wrote, "Any pioneers who travel to Mars will be facing the prospect of death and never coming back. Even if they make it back, there are any number of health issues that could come up. These risks have not stopped people from exploring throughout human history. The bigger question is who to send?"
Other commenters echoed this sentiment, with another reader posting, "Explorers in the past have always been exposed to unusual risks; without the risk takers we would still believe the world is flat."
Beyond the feelings that Mars will be explored anyway, despite the health risks, other commenters highlighted the cost of these missions, with one reader stating, "Sending flesh water balloons to Mars is ridiculous. For the cost of one human on Mars, we could literally probe the entire solar system and map/sample/rove every planet and every major Moon."
Others highlighted the mental and emotional cost of a trip to Mars. "As a devoted sci-fi fan for decades, I always wished I could go into space," another reader noted. "Now that I am 77 years old, I realize I would miss the outdoors. The wind and trees, the birdsong and sweet grass under my feet would be a devastating loss. Let the brave explorers go instead. Life is too brief to leave this planet for the uncertainty and dangers of space travel."
'> 'Life is too brief to leave this planet': Live Science readers share whether they'd go to Mars, despite health risks