Scientists have an unlikely new helper while exploring the Earth’s crust (地壳) deep beneath the ocean: Fin whales. New research, published Thursday in Science, finds these Fin whale calls’ sound waves can help create images of the seafloor down to 2. 5 kilometers.

Seafloor imaging, which is important for studying things like earthquake mechanics and carbon storage capacity, usually uses large air guns that send waves of sound downwards. The sound waves go through the crust and bounce back to instruments on the seafloor, carrying information about the structures they travel through. But such surveys are expensive, and the guns’ explosive noise may interrupt sea creatures that use sound to communicate.

Vaclav Kuna, the study co-author, was studying earthquakes when he noticed strange readings on the seafloor seismic (地震的) instruments, which turned out to match the frequencies of fin whale calls. Whale songs often appear in such instruments’ records, says Emily Roland, a marine seismologist at the University of Washington. Seismologists usually see these signals as annoyance. Kuna, however, noticed that the signals were not coming directly from the whales, but were echoes bouncing back from within the crust.

This technique does have limitations, Kuna says. Fin whale songs are limited in frequency, meaning the subsurface images are not as clear as those made with air guns. Additionally, a relatively flat seafloor is needed to triangulate (作三角测量) the whales’ positions while multiple stations would be needed in uneven or mountainous regions, he says.

Nevertheless, these whales are found almost everywhere except the ice-covered areas of the Arctic. The whale calls’ wide existence means they could provide new insight into old seismic datasets, Roland says. “At least the whale songs can serve as an additional source of signals. They are free and they are always there,” Kuna says. “It’s a win-win.”

Researchers at a university in Hungary say there is truth to what many dog owners always believed. Dogs do understand what humans say.

The researchers made images of the brains of 13 dogs using a machine that records brain activity. The dogs were trained to lie down in the machine for seven minutes. During that time，they listened through headphones to their trainers5 voices. Dog owners may think the news is not surprising. But scientists are impressed.

Brian Hare is a professor of evolutionary anthropology at Duke University. 【小题1】 The brain imaging showed dogs processed words using the left side of their brains,just as humans do. They use the right side of their brains to understand tone and pitch. 【小题2】 Meaningful words said in a neutral way did not have the same effect as the same words said in an encouraging way.

Attila Andies was the lead researcher on the project. “Dog brains care about both what we say and how we say it,” he said. 【小题3】 It’s because dogs have lived with people for a long time. Andies said he thinks other animals probably can understand human language like dogs do. But those animals are not very interested in what humans have to say.

People reacted to the story on Facebook and Twitter. They said they always knew their pets could understand them. 【小题4】 One reader from Virginia said she thought her dog could probably read her mind, too. Someone in California joked that he always knew his dog ignored him. And Greg Matos in Boston called the study “Fascinating!”

When it comes to the smartest species within the animal kingdom, elephants are definitely near the top of the list. Studies have shown that elephants have complex behaviors and survival skills. After all, an elephant’s brain weighs almost 5 kilograms and has three times more neurons (神经元) than a typical human brain.

Elephants have impressive memories. We’ve all heard the old saying “an elephant never forgets” at some point. As it turns out, the saying is based on far more truth than you’d think. Elephants are capable of remembering food and water locations for amazingly long periods of time! Elephants also remember friends and even enemies for several years.

The most well-known method of measuring animal intelligence is the “mirror test”. Most animal species regard their reflections as other animals rather than images of themselves. They may try to fight with their reflection immediately. But elephants are capable of recognizing themselves in a mirror.

When it comes to social intelligence, elephants are also amazingly outstanding! They care deeply for and protect one another within their family groups. Elephants commonly work together to access and share resources like food and water or to protect each other from enemies. In addition, elephants are expert at communication. They use all their senses—hearing, sight, smell, taste, and touch when interacting with each other. Their emotional range is also impressive. They will even get into deep sorrow when a close companion or family member dies.

It turns out that elephants are masters ot using tools like rocks and tree branches for very complex purposes! Their strong, flexible trunks are a huge help to them. Researchers have observed elephants using branches to knock fruits and leaves out of trees so they and their group members can eat them. The use of tools is a key determinant (决定因素) of animal intelligence, as it takes a highly intelligent animal to figure out and remember how to use them.