【推荐1】Female cichlids are mouthbrooding (口育) fish, which carry their young in their mouths first as eggs and then as hatchlings. But in a study published in the journal Biology Letters, the scientists reported that in some instances, cichlid mothers swallow some of their young.

Dijkstra and his coworkers first suspected that something was wrong with their cichlid mothers when they noticed that some of the eggs in one female cichlid’s mouth were missing because the fish can hold up to 100 eggs at once, but in this case, the female was carrying only 25 eggs.

“We realized that one of the mothers wasn’t holding all of her young,” Dijkstra said. “We figured that she probably ate them. There’s quite a bit of literature out there about this phenomenon. It’s very common in a lot of animal species.”

But why would a mother chow down on her babies? The researchers said it likely is because females become desperate for nutrients while they’ re mouthbrooding.

Mouthbrooding also can be a high-stress time for female cichlids, and a prior study of A. burtoni, published in 2020, found that high-stress environments can lead mouthbrooding females to this behavior. In the new study, the authors discovered that some mouthbrooding mothers showed signs of liver damage, with levels of DNA damage that were 24% higher than in non-brooding females.

Horrible as it may sound, this behavior of female cichlids is actually a beneficial strategy for reproduction.

“As a parent, you don’t want to spend all of your energy on one child, and this is also true for humans,” Dijkstra said. “You want to make sure that in the future maybe you will have more children and you still want to be in good enough shape to take care of your existing children as well.”

It’s not only cichlids that exhibit this baby-swallowing behavior. Many different types of animals engage in this phenomenon, including many fish species, birds, insects, spiders and even some large animals.

【推荐3】Cats certainly know the sound of their food can being opened, but do they know their own name? Cats might be skilled in knowing how to always land on their feet, keep themselves clean, and strategically knock things off the counter, but do they know their own names?

“While cats might not always understand what exactly we’re saying. They definitely can learn to associate sounds with good or bad outcomes,” says Mikel Delgado Cat Behavior Expert with Rover. “When you talk to your cat,they probably respond most to your tone of voice. People tend to talk to their pets in higher-pitched voices which are good at getting their attention.”

Cats can also recognize noises that indicate food or attention is coming. They associate those sounds with a positive experience, so they learn to recognize what they mean.

Delgado adds, “Over time, our pets do learn to associate their name with certain things-like attention, or food. You can help your cat learn their name faster by not using lots of different nicknames, which might be confusing to your pet and they may not always realize that you are speaking to them, “Your cat is more likely to respond to their human's voice versus a stranger’s voice.” says Delgado.

You can train a cat to respond to words the same way dogs do. In order to train,Delgado says you first need to identify what motivates your cat, like a particular treat or toy. Then start with something simple such as sit.

“Over time, your cat makes the connections between their behavior, your response or the sound, and the treat,” says Delgado. “Then when they want a treat, you might notice that they offer the behavior you trained-such as sitting or rolling over-which is why it’s a good idea not to train your cat to do annoying things.”

【推荐1】In Central America, scientists have made some recent discoveries about the ancient Maya people. These findings show that the Maya developed their civilization centuries earlier than experts thought. While Europe was still in the midst of the Dark Ages, these Maya had charted the heavens, evolved the only true writing system native to the Americas and were masters of mathematics and calendar. Without advantage of metal tools, beasts of burden or even the wheel, they were able to construct vast cities. Their legacy in stone, which has survived in an impressive fashion at places, lives on as do the seven million descendants (后嗣) of the classic Maya civilization.

Scientists have made some recent discoveries about the ancient Maya people. Experts call the time between the year 250 and the year 1900 the Classic Maya Period. It was a period of great civilization. Until now, scientists think that earlier Maya people were simple farmers. The discoveries show that they used writing, drew pictures and built complex structures. Three separate teams made the discoveries in the rainforest of Guatemala (危地马拉).

Scientists have found some things they say are more than 2000 years old. For example, a team found two masks inside the main pyramid in a city. These masks are three meters tall. They are cut in the image of a sun god. The Maya used the pyramid as a temple. The masks may have been a part of ceremonies led by a king.

At Waka, scientists found the burial place of a woman they think was a Maya queen. They believe she ruled more than 1,200 years ago. Her bones were lying on a stone table. Many jewels surrounded her remains. The team also found pieces of green stone that appeared to be the remains of the kind of war helmet worn by rulers. Scientists say the discovery will help them understand how Maya women shared power with men. Not many burial places of important royal women have been found. Also in northern Guatemala, scientists found a stone showing an 8th-century king playing a game of ball with visiting rulers. It is the third such stone found at the city of Cancuen. They also found large pieces of stone with writing and pictures of leaders. A Guatemalan expert called it one of the greatest masterpieces of Maya art ever discovered in Guatemala.

【推荐2】According to statistics, 358bee species live in the Netherlands, but more than half of them are part of the Dutch red list — a catalog listing endangered species. To support the insects, the city of Utrecht Council, together with advertising agency Clear Channel, has transformed 316 bus stops across the city into “bee bus stops”. They are like ordinary bus shelters, but small gardens have been added to the roofs. The gardens are filled with grass and wildflowers chosen to attract bees.

The city authorities put the project out to tender (投标). In the tender, they outlined the requirements and encouraged applicants to develop a nature-inclusive design that offers ecological benefits to the city. Finally, they signed an agreement with Clear Channel, who won the tender and setup 316 bus shelters. The project didn’t cost the city government anything. The operators are responsible for the upkeep of the stops citywide, using income from advertising.

The bus shelters have brought about great changes in the city. Green roofs catch fine dust, store rainwater and provide cooling in the heat. They also ensure biodiversity in the city. There are also 96 bus stops fitted out with LED lighting and bamboo benches. The base plate is also made from recycled concrete. The advantages of the bus stops have not gone unnoticed by the media. But what particularly has caught the media’s attention is that these eco-friendly shelters make people happy and enthusiastic, and encourage them to do something for nature.

This unique Dutch city even has a program for residents who can transform their own roofs into green roofs for bees. Residents interested in this can apply for government allowances. Click here for more information and details.

【推荐3】A retired couple in the Netherlands have moved into Europe’s first fully 3D-printed house. The two-bedroom bungalow (平房) in Eindhoven is the first of five homes planned on the site in the coming months, using a huge 3D-printer. It’s part of some special teamwork between Eindhoven University of Technology and the Vesteda housing company called Project Milestone.

This house was designed by an architect and printed using a huge robotic arm in a special warehouse (仓库). The printer uses a nozzle (喷嘴) that squirts out special substance to print out the building, layer by layer.

Once the house had been printed it was transported by vehicle to the building site where it was placed on a foundation, and a roof and windows were added.

In the longer term, many in the building industry believe that 3D-printed homes could become a sustainable solution for tackling housing shortages. The technology is friendlier to the environment and reduces costs because it uses less concrete and homes are quicker to build. The new home took just 120 hours to print, much quicker than building a house in the traditional way, which can take around 1-2 years to build.

The new owners Elize Lutz and Harrie Dekkers, will pay $800 a month to live in the house for six months, after they responded to a request for volunteers.

“I saw a drawing of this house and it looked exactly like a garden,” said Elize. “It’s beautiful.” “It feels safe,” added Harrie.

Construction companies in the US and France have already been using 3D printing to build parts of homes, but this one is the first to be fully built and have people live in it.