Just like humans, birds rely on sound to communicate, too. Often, birds recognize their mates or young by sound rather than sight. Hungry young birds use begging calls to let their mothers know it is feeding time, and warning calls are other sounds given out frequently by the adults. In addition to all these regular calls, some male birds develop beautiful songs intended（打算）to attract the females.

A new study carried out by an American university shows that songbirds practice their songs even in their sleep. The research team discovered that the electrical brain activity of the birds that were asleep was similar to the brain activity produced when the birds were awake and singing. Clearly the bird stores a song after hearing it, then practices it later in its sleep. Scientists now believe the birds dream of songs to help them master the fine art of singing and that sleep plays a key role in the learning process！

It is commonly known that many songbirds learn to sing by listening to adult birds of the same species. If taught the song of an adult of another bird species, the chick grows up singing the new song and passes on the foreign song to its chicks. For instance, researchers carried out an experiment in which a male bullfinch（红腹灰雀）was raised by a female canary（金丝雀）. The bullfinch soon learned the canary's songs and when it was later mated to a female bullfinch, Mr. Bullfinch taught his children the canary's songs.

Early last year, a British survey of London's songbirds showed that the city's birds are losing their melodies. Birds could hardly hear one another over the traffic noise；as a result they had difficulty in learning songs and communicating with potential mates. And instead of copying the sweet notes of the adults, chicks were copying sounds, which they heard most often—namely car horns（喇叭）and mobile phones！

   Penguins are the number-one attraction for many visitors to Antarctica. If you go on a ship that is allowed to make shore landings, you may see them. But to get a close look at penguins, you have to be smart.

First of all, keep in mind that Antarctica’s visitor rules require that you remain at least five meters away from the penguins in order not to disturb them. You could easily become responsible for the death of a little penguin or the destruction of an egg if your too-close presence should disturb a penguin parent.

If a penguin is trying to move away from you, you must stop what you’re doing and back off even if you’re farther than five meters away. However, the rules don’t prevent a curious penguin from approaching within five meters of you — as long as the bird makes the move, not you.

Little penguins, in particular, are quite curious. I’ve seen several lucky tourists who were astonished to find that little penguins came right up to them. If a penguin comes extremely close to you, remember that you are not allowed to touch or hold it.

Here are more tips for getting close to penguins.

Ignore the smell: where penguins live is filled with guano（海鸟粪）and the smell takes some getting used to.

Be quiet because loud noises make penguins nervous. Fast or sudden movements signal meat — eating animals to penguins, and they react accordingly, so slow down when you walk around them.

Since it may take half an hour or more before the penguins get used to you, you need to be patient. Put away your camera — too often people are so focused on getting the pictures that they forget to look with their own eyes, but most of your most memorable experiences in Antarctica will be marked in your mind, not on a roll of films.

   Many years ago in a zoo，I was shocked by finding that chimpanzees could behave in a more civil manner than youths. Great apes（类人猿）are always one of the favourite attractions in any zoo. The main reason for this is that they are so similar to us.

This similarity has persuaded a group called the Great Ape Project（GAP）to campaign for these animals to be afforded“human rights”.

This has resulted in laws in New Zealand，which could mean that great apes would become the first animals in the world with basic rights protected by the law.

Not everybody is happy with this idea，however. Scientists using animals for scientific research fear that this is just the first stage in a process that will lead to a ban on using all animals for research.

The GAP declaration claims great apes should have“human rights”due to scientific evidence about their abilities. But if we compare the abilities of humans and great apes，then why not the abilities of great apes and monkeys，monkeys and lemurs，and so on until insects are granted“human rights”？This is not foolish. There are people without basic human rights. How long ago，for example，did women not have the right to vote？

Yet another argument by those who don't support GAP is that the human-like qualities of great apes have been exaggerated（夸大）for certain reasons，and that this has led people to exaggerate the similarities but ignore the differences between humans and great apes.

In a fascinating book entitled What It Means to be 98% Chimpanzee，Jonathan M. Marks points out that，although a human and a daffodil（水仙花）share the common ancestry and their DNA matches more than 25% of the time，it is plainly ridiculous to claim that we are one-quarter daffodils.

He goes on to demonstrate that，if looked at from one angle，it is true that we are apes phylogenetically. But also fish from another angle！“It doesn't sound quite so profound now，does it？”

   Dogs will do absolutely anything for the people they love，and for one North Carolina dog，that meant _________his own life in order to save his best friend.

This past Saturday morning，a deadly fire _________in an apartment building that left multiple families and their beloved pets _________inside waiting for help to arrive. "My wife got a phone call and it was very  very _________because she had her on the speakerphone and my daughter was very  very _________ and she was screaming that the apartment was on fire，"said Mare Martinez，whose daughter Karina was _________in the apartment when the fire started.

Karina had no _________ that her life was in danger until her dog，a 2-year-old German Shepherd named Riddick，woke her up with his panicked _________."Her dog wouldn't settle down so she called him up on her bed to cuddle（依）him，"Martinez explained." _________，he was still sitting up and __________barking at the wall."

After __________there was a fire，Riddick helped guide Karina to safety. "She went down the landing（楼梯平台）because there were already flames，but the dog got __________and went back up and would not come down，"said Martinez __________，she couldn't get Riddick to come back down and he __________before firefighters could rescue him." He was her best friend，they were __________and he did what he was supposed to do. He __________and took care of her when she was in danger.”

"The great Greenville Fire and Rescue department of the city did us very  very __________.They made this even just a little bit more tolerable，"said Martinez，who was __________when they went into the building and got back Riddick's __________ so they could give him a proper __________.