Have you ever heard that there is a special fishing team? It is made up of human fishermen and dolphins in the coastal city of Laguna in Brazil. They work together to catch fish.

Mauricio Cantor from Oregon State University, US, studied this partnership (合作关系). As he told Science News Explores, the cooperation started more than a century ago.

“ The dolphins are good at finding fish in the cloudy water and driving them to the coast,” Cantor said.

“The fishermen are really good at trapping the fish with their nets.” Once the fish are caught in the nets, dolphins can move in and get some for themselves. By working with dolphins, fishermen catch more fish, and dolphins are more successful in hunting, too.

Cantor’s study described how fishermen and dolphins give signals (信号) to each other during fishing. When dolphins find fish, they drive them to the coast. Then they raise their backs in front of the fishermen to tell them to throw nets. Fishermen will then throw the nets right away, or they may lose the best chance. Fishermen need to be well-trained to understand the signals from dolphins, said Cantor.

The study found that fishermen are 17 times more likely to catch fish by working with dolphins. At the same time, cooperative dolphins have 13 percent higher survival rates (存活率) than other dolphins.

Human-animal partnerships have been rare throughout history. But they “give us an idea of how active our human interactions can be with nature,” Cantor said.

African penguins stand only 50 centimeters tall. Like people, each penguin has its own voice. They live along the southern coast of Africa. Like all the other penguins, they hunt fish in the ocean and lay eggs on land. But they are smaller than their well-known cousins in Antarctica and larger than little penguins in Australia and blue penguins in New Zealand. But the African penguins have a problem — they are endangered.

The African penguins used to nest (筑巢) underground in the guano, or bird poop (粪便). The guano came from the penguins and other seabirds. Over hundreds of years, it had built up to form a thick layer as deep as 3 meters.

However, in the 1860s, people began collecting the guano to use it on farms. Now there’s no more guano to make nests. The penguins have to lay their eggs in the open. As a result, the penguins often get too hot. When the parents leave the eggs to cool themselves down in the water, other animals can easily find the eggs and eat them.

Some scientists wanted to help. They created artificial (人造的) nests to protect the African penguins. But the penguins didn’t use them. The nests often got too hot.

To solve the problem, the scientists set up an artificial nest project in 2016. They came up with criteria for the nest. It had to protect penguin eggs from being eaten. It couldn’t flood in the rain. And it needed to keep penguin families cool. The scientists built 15 kinds of nests to find the perfect one. Finally two of them stood out. Both of them could let air flow through. The scientists plan to build more than 2,500 nests for the African penguins in the future. They hope the new nests can help increase the number of the endangered birds.