For nearly every step of his almost 12-mile walk, Darryl Dyer has company. Flocks of crows follow him, signaling each other, because they all know that he’s the guy with the peanuts.

“They know your body type. The way you walk,” Dyer said. “They’ll take their young down and say: ‘You want to get to know this guy. He’s got the food.”

Scientists for years have known that crows have great memories, that they can recognize a human face and behavior, and can pass that information onto their babies.

Nowadays, researchers are trying to understand more about the crow’s brain and behavior, specifically what it does when the birds see one of their own die. They react loudly to the dead, but the reasons aren’t entirely known. Among the guesses is that they are mourning; losing a partner could be a significant moment for the social animals. Crows place sticks and other objects on dead birds—a funeral of sorts.

“Crows have evolved to have these complex social relationships, and they have a big brain,” said Kaeli Swift, who led the study.

How big of a brain? Crows are on par with smart mammals, like dolphins and monkeys, in brain-to-body proportion (比例). They have been known to be problem solvers and are among the few animals recorded to use tools.

In another part of the experiment, using slightly radioactive tracers, researchers measured the brain activity of crows after they were shown a dead bird. The scans showed the section of the hippocampus-the part involved in memory formation-light up at the sight of death. “In that particular situation at least, that crow was learning about a place, or a face, or a situation and associated it with that dead crow,” said Johin Marzluff, the lead researcher.

If a woman has an extra piece of cake, don’t blame it on greed, blame it on her brain.

Scientists have found that women’s brains react to food very differently — and much more strongly — than men’s. Academics found that decades of dieting pressure on women and advertising have programmed certain parts of the female brain to react strongly when faced with any kind of food. Men, on the other hand, are not usually as obsessive (着迷的) about what they eat.

Dr. Rudolf Uher and his colleagues at the Institute of Psychiatry in King’s College London used brain scanning technology, known as functional magnetic resonance imaging (FMRI), to look at the brains of eighteen men and women.

The volunteers were given images of food to look at, as well as food to taste. Their brain reactions were observed by the scientists.

They found that the female brains reacted much more strongly than those of males.

The same reaction did not happen when they were shown non-food images. The team believe this means women think more about food than men tend to do.

Dr. Uher said, “This could be related to biological differences between men and women. But the more likely explanation is that women have a more complicated reaction to food because of social pressure.

Professor Carey Cooper, psychology and health professor at Lancaster University, said, “For centuries women have had a providing role — preparing and cooking food for their families. And it is part of that rule to make sure the food is safe. They will therefore be much more sensitive to food than men are, and I would not be surprised if that was now built into their DNA. If the female brain reacts to food because it historically has developed neural (神经的) pathways to do this, then food will be the way they express their stress. Food actually, is a comfort for women.”

But other experts have said that more research must be done before the results can be proved. American scientist Angelo del Parigi of the John B. Pierce Laboratory in New Haven, Connecticut, said, “Looking at an FMRI alone cannot make sure whether the stronger reaction in women is due to innate (天生的) differences or a learned process.”

Climate change is drying out rivers, supercharging wildfires, raising seas and changing the seasons as we know them. These disastrous changes to the environments we depend on for food and shelter are also harming our mental health.

“We’re seeing a lot of anxieties in research, especially as more people start to understand that climate change is a very real phenomenon,” says Derrick Sebree, a psychologist (心理学家) at the Michigan School of Psychology.

A recently published UN report noted that mental health cases are resulting from extreme weather and rising temperatures. It also warned that these extreme conditions are only going to worsen. In 2017, the American Psychological Association argued that therapists (理疗师) will be almost as important as cooling centers to help people deal with a changing planet.

When Hurricane Katrina struck New Orleans, the storm and resulting floods killed nearly 2,000 people and damaged nearly 300,000 homes. A study of 400 people found a quarter experienced post-traumatic stress disorder (PTSD) for two years following the storm.

Therapists treating natural disaster survivors say mental health issues may not always appear immediately. “Two to three years later, somebody may think they are doing great, but actually they’re not,” says Dix Moore-Broussard, a therapist who experienced Katrina and treated those who suffered PTSD from it.

Along with the typical symptoms (症状) of PTSD, like anxiety, Moore-Broussard says she saw patients who had deep worry about what might happen in the future, which can badly affect normal brain function. People who had been impacted by natural disasters also struggled to focus and process their thoughts.

Psychologists are taking climate change seriously. They help patients find local therapists who have signaled an interest in treating climate-related disorders. “People experiencing climate anxiety tend to care about the environment and can benefit from spending time outdoors,” says Derrick Sebree. He adds that spending time in nature improves both mental health conditions and physical conditions.