The manta ray is one of the largest fishes in the world, reaching up to 29 feet in width. And manta rays are some of the friendliest creatures. They allow divers to swim right up to them. Unfortunately, these gentle animals are in big trouble. Since 2011, manta rays have been listed as a threatened species worldwide.

Overfishing is considered the biggest threat to giant manta numbers, both intentional and accidental. People catch manta rays for their gill plates — the parts through which they filter their food from seawater — are sold in China for medical purposes. Driven by the huge demand, fishermen have hunted them mercilessly. From 2010 to 2013, the number of rays killed annually to supply the gill plate market tripled to 150,000. Clearly, overfishing is bad for any sea creature, but it’s even worse for giant manta rays. Female mantas usually have only one baby, every two to five years. So every manta ray that was caught hurts the population in a big way.

To protect giant manta population, Peru, a country in South America, recently took a big step to protect giant manta rays. It banned fishing for them. People who break the law can be fined or have their fishing licenses taken away. Even manta rays caught accidentally in fishing nets must be released. Although other countries have passed laws to protect manta rays, Peru’s may be the most important one yet, because there are more giant manta rays in the Pacific Ocean near Peru than in any other place in the world.

Scientists working in the Manta Trust, an organization that researches manta rays, are also trying to protect manta rays by learning more about them. Earlier this year, the organization attached video cameras, called Crittercams, to manta rays off the west coast of Mexico. The photos the cameras collect could help researchers predict where and when manta rays swim. The scientist could use the information to warn fishing boats to avoid these areas, helping reduce the number of accidentally caught manta rays.

___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Elephants can tell

It is easy for us to tell our friends from our enemies. But can other animals do the same? Elephants can! They can use their sense of vision and smell to tell the difference between people who pose a threat and those who do not.

In Kenya， researchers found that elephants react differently to clothing worn by men of the Maasai and Kamba ethnic groups. Young Maasai men kill animals and thus pose a threat to elephants； Kamba men are mainly farmers and are not a danger to elephants.

In an experiment conducted by animal scientists， elephants were first presented with clean clothing or clothing that had been worn for five days by either a Maasai or a Kamba man. When the elephants recognized the smell of clothing worn by a Maasai man， they moved away from the smell faster and took longer to relax than when they recognized the smells of either clothing worn by a Kamba man or clothing that had not been worn at all.

Clothing color also plays a role， though in a different way. In the same study， when the elephants saw red clothing not worn before， they reacted angrily， as red is typically worn by Maasai men. Rather than running away as they did with the smell， the elephants acted aggressively（攻击性地） toward the red clothing.

The researchers believe that the elephants’ emotional reactions are because of their different understanding of the smells and the sights. Smelling a potential danger means that a threat is nearby and the best thing to do is run away and hide. Seeing a potential threat without its smell means that risk is low. Therefore， instead of showing fear and running away， the elephants express their anger and become aggressive.