Why do animals migrate or move? They do so to find a place that will offer better living conditions. Not all animals migrate, but those that migrate are attempting to help the survival of their species. There are a variety of reasons why animals leave. Some migrate to avoid weather changes. Some leave because of the food supply. Unlike humans who migrate because of relationships, job changes, or other social reasons, animals migrate to survive.

There are different types of migration, but one of the most interesting is the seasonal migration. In seasonal migrations, animals move twice a year. These movements usually occur due to changes in the seasons or in the weather. For example, some birds migrate away from colder regions to warmer weather and then come back to a place once the colder weather has passed.

How do animals know when it is time to migrate? Some animals do not leave an are until the environment changes and becomes a place that is not favorable for them to live. Other animals seem to have inborn systems that tell them when it is time to leave.

Animals that migrate use many different ways to successfully reach their destinations. Scientists believe animals’ senses play a huge role in helping them find their way. For example, salmon(三文鱼)are thought to recognize specific smells that help them. Others are thought to use even the sun, moon, and stars to help guide them on their journeys. Although the animals use different methods to migrate, one thing is the same: migration remains an important journey for the survival of many of Earth’s most amazing species.

Patients with memory loss will often remember songs and specific song lyrics (歌词) . Doctors will often use music and lyric recall to help individuals recover lost memories. Music and its effect on memory has been a heated debate in the scientific world, but research now has found the evidence that music can get results on the job.

University of Kansas Medical Center researchers conducted an experiment where they divided 70 healthy adults, aged 60 to 83, into three groups based on their amount of musical experience: no musical training, one to nine years of music lessons and at least 10 years of musical study.

The participants, who had similar fitness and education levels and were free of Alzheimer’s disease, were given several cognitive (认知的) tests:

●Those with the greatest amount of musical experience did best on these tests of mental sharpness followed by those with less musical study followed by those who never took music lessons.

●Compared to non-musicians, the individuals with a high degree of musical experience had much higher scores on the cognitive tests, including those related to visual and special memory, naming objects and the brain’s ability to adapt to new information.

●The really cool part? The benefits of musical study and training were still obvious even in participants who no longer played an instrument.

Music and musical training have been shown to protect the aging brain and keep it healthy. Here’s a story about the power of music from Kimberly Hersey, whose father has Alzheimer’s:

“As a family, we didn’t know what to do when our father was diagnosed (确诊) with this Alzheimer’s disease. We have been through so many stages and now he seems to just be worsening to nothing. However, the music seems to have brought back some of his brain to him!”

Now, you can tell your mom that those hours of musical practice for high school band were totally worth it.

Can a fish be depressed? This question has been on my head ever since I spent a night in a hotel across from a sad-looking fish. His name was Bruce Lee.

The pleasant woman at the front desk assured me that he was well taken care of. Was I incorrectly assuming his laziness was a sign of being upset?

When I sought answers from scientists, I assumed that they would find the question ridiculous. But they did not. New research has been totally shifting the way that scientists think about fish cognition (认知)，building a case that pet and owner are not nearly as different as many assume. The neurochemistry (神经化学）is so similar that it’s scary, said Julian Pittman，a professor. We tend to think of them as simple living things, but there is a lot we don't give fish credit for.

Dr. Pittman likes working with fish, in part, because they are so obvious about their depression. A zebrafish gets dropped in a new tank. If after five minutes it is hanging out in the lower half, it’s depressed. If it’s swimming up top, then it’s not.

Is depression the right word? There's the obvious issue that we cannot ask animals how they feel, says Dr. Diego A. Pizzagali . Neither fish nor rats can catch the entire range of depression as we know it.

There is a heated debate about whether anxious or depressed is a more appropriate term. But what has convinced Dr. Pittman, and others, over the past ten years is watching the way the zebrafish lose interest in just about everything: food, toys, exploration, just like clinically depressed people who are withdrawn. The same is true of fish.

One of the things we're finding is that fish are naturally curious and seek novel things out, said Dr. Braithwaite. In other words, your goldfish is probably bored. To help get rid of depression, she urges introducing new objects to the tank or switching up the location of items.