Everybody hates rats. But in the earthquake capitals of the world-Japan, Los Angeles, Turkey-rats will soon be man's new best friends.

What happens after an earthquake? We send in rescue dogs. Why? Because they can smell people. Dogs save lives. They help rescuers to find living people. But dogs are big and they can't get into small spaces. So now a new research project is using a smaller animal to save lives: the rat.

How does it work? First，the rat is trained to smell people. When this happens, the rat's brain gives a signal. This is sent to a small radio on its back, and then the rescuers follow the radio signals. When the rat's brain activity jumps, the rescuers know that someone is alive. The rat has smelled that person.

Although there are already robots which can do this job, rats are better. Christian Linster at Cornell University-New York says, “Robots' noses don't work well when there are other smells around. Rats are good at that.” Rats can also see in the dark.They are cheaper and quicker to train than dogs, and unlike robots, they don't need electricity!

The “rat project” is not finished, but Julie Ryan of International Rescue Corps in Scotland says, “It would be fantastic. A rat could get into spaces we couldn't get to and a rat would get out if it wasn't safe.” Perhaps for the first time in history, people will be happy to see a rat in a building (but only after an earthquake, of course).

From old times, crows(乌鸦)have been famous for their cleverness. They use tools, work out problems, and even enjoy playing. Scientists have studied carefully how crows go about these activities.

To make tools, crows cut off leaves with their ''mouths'', shape them, and use them to look for bugs(虫子)in wood or plants. Just as a carpenter carries his tools with him, a crow will carry its tool around. When the leaf isn’t needed for the moment, the bird stores the tool at its feet or somewhere else.

To test wild crows' abilities to work out problems, scientists placed food outdoors in covered bowls. They watched with interest as the birds smartly opened the bowls to get the food. Scientists also found out that crows can make use of the traffic. For example, crows would drop a nut on the road and wait for a car to run over the nut to break it.

Besides, crows seem to enjoy playing. Young crows will carry a stick or nut into the air, drop it, and fly to catch the object as it falls.

So just how smart are crows? Perhaps a crow will never do tricks as a dog will. But scientists agree that there’s a lot going on in the brain of a clever crow.

Parrots live extremely long partly due to their relatively large brains, an international team of researchers has discovered. Simeon Smeele, a doctoral student at the Max Planck Institute of Animal Behavior, led the study, the results of which were published in March in the Proceedings of the Royal Society.

When it comes to lifespan (寿命), birds truly stand out. Lifespan tends to increase with an animal’s body size, roughly speaking. Thus, the bigger the animal, the longer they live. But a bird tends to live much longer than a comparably-sized mammal. One theory is that birds’ ability to fly means they are less at risk from the animals that kill them, which reduces their risk of being eaten, decreases stress, and frees up bodily resources for growth.

And among birds, parrots are the aging champions. The confirmed longest-living bird was Cookie, a Major Mitchell’s cockatoo (a species of parrot), who lived at the Brookfield Zoo in Illinois for all but one of his 83 years. Though cockatoos often weigh around a pound, they usually live for four decades. Most of the other 398 parrot species also live longer than other birds of similar size.

What sets parrots apart? In the new research, Smeele and his colleagues gathered data on over 130,000 individual parrots held in more than 1,000 zoos, representing 217 species. Through this data, they created reliable estimates of the average lifespan for each species. They next searched for a link between each species’ lifespan and its relative brain size and found a clear, positive correspondence. Parrot species with larger brains relative to their body size lived longer than species with smaller brains.

“This supports the idea that in general larger brains make species more flexible. For flexibility allows them to live longer.” Smeele said in a statement. “For example, if they run out of their favorite food, they could learn to find something new and thus survive.” He added, “All parrots have relatively large brain sizes compared to most other birds.”

Researchers have previously shown that, when trained, some parrots can recognize and understand objects, colors, and shapes, and even speak with an impressive vocabulary. They can even match five-year-old humans on basic tests of intelligence.