The world's first-known nursery for baby giant manta rays(蝠鲼) has been discovered hidden away in the Gulf of Mexico, the place of 70 miles off the coast of Texas, after studying decades of giant manta ray data from the area by the scientists.

    Where the baby manta rays grow up has long troubled scientists, as they are rarely spotted in the four to five years it takes them to become adults, when they can often grow to more than 20ft wide.

In the study Mr Stewart and colleagues describe a reef (暗礁)—filled with mantas of all ages—where the sea floor runs down into deeper water. He said "We think they may be feeding on specific types of zooplankton(浮游生物) there, then migrating up toward the surface, where we saw them. They might be hanging around the banks because it could be a little safer than open water. We've seen them so rarely that we know very little about these baby manta rays. We don't know how far they move, or exactly what they feed on, or all of the habitats these access.”

    Giant manta rays are listed as species dying out by protectors, although actual population numbers of the mysterious "gentle giant" are hard to calculate. Sightings of the closely-related reef manta, however, have dropped by 90 percent in regions of southeast Asia in the past decade, according to a study.

    Fishing is considered the biggest threat to giant manta numbers, both intentional and accidental. Their gill plates(腮下肉)- the parts through which they filter(过滤) their food from seawater-are sold in China for medical purposes, while they often end up as something caught by mistake due to their huge wings.

    You're sitting on the sofa, and there's your dog, right at your feet. You stand up? He stands up. But then you head to the bathroom, and guess who comes with? Why, your dog, of course. But why? Why does your dog follow you like a shadow, no matter where you go?

    Ever get the feeling you're being followed? As for why your companion follows you everywhere you go, read on!

    "When dogs follow their owners, there can be several scientific explanations, depending on the dog and the individual situation," according to Mary Burch, Ph.D., an animal behaviorist(行为学家).

    These explanations include:

    Positive reinforcement(正面强化): When your dog follows you, good things happen. Think dog food, a hot bath and taking a walk around the neighborhood. Your dog's no dummy. And one of his many talents is learning from experience, that is "reinforcement."

    Natural instinct(本能) to be part of a pack: In fact, a study out of Princeton University that was published in the journal, Science Advances, shows that your dog's drive (驱动力)to follow you around (as well as watch you attentively and seek physical contact (身体接触) from you) lies in his genes(基因).

    Feel good chemicals(化学物质): Your presence causes your dog's brain to release "feel good" chemicals, Dr. Primm explains, citing this study. Considering how much we as humans enjoy those feel-good chemicals, it's no surprise your dog likes them too—and will follow you around to get some!

    Sense of responsibility : As you move about your home, your dog might feel that you are patrolling your territory (巡视领地) and take on the duty to assist you.

    People often say that there is nothing in the world that can be as great as a mother's love. Some mother expressions mean just that. The phrase "mother lode" comes from mining. It means the place where the largest amount of gold can be found. But now, the term "mother lode" means a rich supply of anything. For example, you might say, "She just graduated from college and struck the mother lode with her new job!"

    When we call something "the mother of all", this means it is the biggest or best of something. Here is an example: "We are going to throw the mother of all parties this weekend. So you have to come!"

    Naturally, the word "mother" can be used to mean to give birth, even to something you cannot touch, such as an idea or wisdom. The saying "necessity is the mother of invention" means that when people really need to do something, they will find a way to do it. And "experience is the mother of wisdom" means that people learn from what happens to them.

    You might think all expressions about mothers are sweet and loving. Not so. A boy who is "tied to his mother's apron strings(围裙带)" is controlled by his mother. We can also call him a "mama's boy". Both of these terms are even more insulting(侮辱人的) if you are talking about a man, not a young boy. It can be a huge mistake for a woman to marry a "mama's boy" who is still "tied to his mother's apron strings".

    A show about mothers would not be complete without talking about the very popular but mysterious "Mother Goose". The short poems and songs that "Mother Goose" wrote are a part of growing up in the United States. Real or not, you could say "Mother Goose" is the mother of all nursery rhyme(童谣) writers.

    Learning is so complex that there are many different psychological theories to explain how people learn. A psychologist named Albert Bandura suggested a social learning theory which shows that observation, imitation (模仿), and modeling play a primary role in this process.

    In Albert Bandura's opinion, people can learn through observation. Observational learning doesn't even necessarily require watching another person join in an activity. We can also learn by reading, hearing, or watching the actions of characters in books and films. However, just observing someone else's actions isn't always enough to lead to learning. Your own mental state also plays an important role in determining whether a behavior is learned or not. In addition, though in many cases, learning can be seen immediately when the new behavior is displayed, yet sometimes we can learn things even though that learning might not be immediately obvious, which means people can learn new information without showing new behaviors.

    Not all observed behaviors are effectively learned. Certain requirements need to be related to the observational learning process. For example, you need to be paying attention. Also your retention is an important part of observational learning as you need to pull up information later and act on it during the process. Once you've paid attention to the model and kept the information, it's time to actually perform the behavior you observed. Further practice of the learned behavior leads to improvement. Finally, you have to be motivated to imitate the behavior that has been modeled.

    Social learning theory have many real-world applications. For example, researchers employ it to look into and understand ways that positive role models can be used to encourage desirable behaviors. Besides, it's also applied in the field of education, and today, both teachers and parents recognize how important it is to model appropriate behaviors.

    The world maps will soon be altered to reflect an eighth continent! Dubbed "Zealandia" the landmass that lies east of Australia covers 4.9 million km. Over 94 percent of it is submerged (淹没的) in the southwest Pacific Ocean, with just the islands of New Zealand and New C aledonia visible above sea level.

    To be clear, the underwater land is not a recent find. Researchers have known about its existence since 1995 when Bruce Luyendyk discovered and proposed an eighth continent that he called Zealandia. At the time, the area was dismissed as a collection of islands and land fragments (碎片), or at the most, classified as a micro continent—a landmass of continental crust that is not geologically connected to the nearest continent, in this case, Australia.

    However, after observing the areas features on an underwater topography map, New Zealand geologist Nick became convinced that Zealandia is a continent. Mortimer says that while Zealandia is much smaller than our seven continents, at over half the size of Australia, it is unfair to classify it as a microcontinent. The geologist argues, “If you could pull the plug on the world's oceans, then Zealandia would probably long ago have been recognized as a continent.”

    Geologist Christopher Scotese argues that too much of the landmass is underwater, asserting it's "almost a continent the way Pluto is almost a planet." Richard Ernst, a geologist, proposes coining a new term minicontinent—for Zealandia. He thinks this is perfect given that it is too large to be called a microcontinent and too small to be classified as a full-sized continent. Given that there is no international panel to decide the fate of Zealandia, its future as a continent is uncertain. Mortimer hopes that if supporters start using the term Zealandia, it may eventually catch on. Whether that happens remains to be seen, but for now, we will have to be satisfied with just seven continents!