A long-term American study shows the effect of early education on future learning abilities. The study followed more than 1,300 children from birth through the ages of ten or eleven years. The study is known as the Human Development Study of Early Child Care. It is said to be the largest, longest lasting and most complete study of child care in the United States. The children included in the study were born around 1991 in ten areas of the country. Researchers examined the quality and amount of child care the children received until they were 54 months old. Child care included any care provided by people other than the child’s mother that lasted at least ten hours a week. This included any care given by fathers or other family members. The researchers then examined cach child’s performance in school and social development. They also measured other influences, such as the quality of classroom education and parenting (教养).

Recently, the researchers examined whether the developmental qualities that bad been observed in young children were still present a few years later. They found that the older children who had received higher quality child care continued to show better ability in measures of language skills. The children’s understanding was observed using a method which shows their ability to name objects shown in some pictures. The study confirmed a link between high quality child care and better test results continued as the children grew older. It also found that the children’s ability was not dependent on the amount of time they had spent in child care.

Interestingly, children who had been in child care before entering school were also more likely to have shown aggression (攻击性) or refusal to obey in their early school years. However, the researchers said the children’s behavior was considered normal.

In the animal kingdom, mimics (模仿) are not rare. Stick insects pretend to be twigs. Hawk moth caterpillars resemble poisonous snakes. The examples, though, are visual. Auditory mimicry is rarer. Danilo Russo of the University of Naples Federico II thinks he has found a novel case of it, as he describes in Current Biology. Some bats, he believes, mimic angry bees in order to scare away owls that might otherwise eat them.

Dr. Russo first noticed bat buzzing a few years ago. The noise struck him is similar to the sound of some bees. He wondered whether bat buzzing was a form of mimicry which helped to scare off would-be predators.

To test this idea, he and his colleagues first recorded the buzzing that captured bats made. Then, with protective clothing, they began the more dangerous task of recording the buzzing made by different bees. Computer analysis revealed that bees’ and bats’ buzzing were, indeed, similar.

Then the researchers recruited several owls. They put the owls, one at a time, in an enclosure with branches for them to stay on, and two boxes with holes in them. They placed a loudspeaker alongside one of the boxes and, after the birds had settled in, broadcast through it five seconds of uninterrupted bat buzzing and a similar amount of insect buzzing three times in a row for each noise. As a control, they broadcast in like manner several non-buzzing sounds made by bats.

During the broadcasts and for five minutes thereafter, they videoed the owls. After analysis, the results were unequivocal. When they heard both the bat buzzing and the bee buzzing, the owls moved as far from the speakers as they could. In contrast, when the non-buzzing bat sounds were played, they crept closer.

Dr. Russo believes this is the first reported case of a mammal using auditory mimicry to scare away a predator. They strongly suspect, however, that it is not unique. Anecdotes suggest several birds also make buzzing noises when their nests are disturbed. And with the result of the experiment, he therefore predicts that auditory mimicry is far more widespread than currently realized.

Daphne Soares, a biologist, made an amazing discovery about alligators (短吻鳄). The investigation of the sensory dots of alligators began when she was at university. Now she holds a research position at the University of Maryland.

The first time Daphne Soares got really close to an alligator was when she was helping to hold down an eight-foot alligator. When she got close to the alligator, she noticed that its face was covered with little black spots.

She started her study of the black dots when she went to the library. When she read the books and the scientific journals, she learned that people had noticed the dots. People thought that the dots were some kind of sense organ. However, no one really knew what the dots were for.

It was a complete accident when she found out what the dots were used for. She placed electrodes (电极) on nerves coming from some of the sensory dots. When the nerves were stimulated, they created a tiny electric current. Just then she heard a small sound over a audio speaker. She tried to see if the dots acted like eyes and temperature sensors, but nothing worked. One day she accidentally dropped a tool into an alligator’s tank. When she put her hand in the tank to get the tool out, she made small ripples (涟漪) in the water. When the ripples reached the alligator’s face, she heard a noise over the speaker. She then realized that the dots must be sensitive to the changes in pressure when they were hit by ripples of water.

After that, she is now studying blind cavefish. She is trying to learn whether they are blind from birth or lose their sight as they grow up.