1 . Gorillas (大猩猩) in films such as King Kong and Tarzan are wildly beating their chests when under threat. Researchers have tried to find out what the behavior might mean, and they doubt that the gorillas exhibit this behavior not to start fights, but to prevent themselves — and chest-beating could be used to advertise their body size to other gorillas.

Scientists observed 25 wild male mountain gorillas for over 3,000 hours. The research team used audio (音频) equipment to record the sound frequency, rate, duration, and amount of chest beats. To determine each gorilla’s size, the researchers used cameras to photograph and measure each gorilla’s back.

Although the rate, duration, and amount of beats did not correlate with the size of the gorillas, sound frequency did , the researchers report. The team also noticed that larger gorillas produced deeper-tone chest drumming. Previous research has shown that a gorilla’s larger body size is linked to reproductive success and social rank. The chest-beating could be a way for the gorillas to advertise their size to others and, in turn, avoid fights that could result in serious injury or death.

Though gorillas can obviously observe size just by getting a good look at others, the researchers suggest chest beating is copper-bottomed when trying to communicate through a thick forest. The sounds gorillas created by beating their chests are powerful enough to travel long distance through thick forests and signal others their size and fighting ability.

Animal expert Anna Nekaris says it would be interesting to see if smaller gorillas can imitate the deep tones of larger ones in future studies. Nekaris says, “For now, the researchers will continue to study chest-beating to see if the action can pass on other information, such as dominance rank, sex, and individual identity, to nearby gorillas.”

1. What is the second paragraph mainly about according to the research?

A．Its findings.

B．Its purpose.

C．Its samples.

D．Its method.

2. Why do some gorillas beat their chests?

A．To declare war on other gorillas.	B．To frighten other gorillas away.
C．To welcome their companions.	D．To celebrate their victory in a fight.

3. What does Nekaris suggest researchers’ study in the future?

A．If smaller gorillas can make deep-toned chest drumming.

B．If gorillas’ chest-beating contains other information.

C．If larger gorillas are better at using their body influence.

D．If gorillas have other communication skills.

4. Which section may the passage come from in a newspaper?

A．Health.

B．Entertainment.

C．Science.

D．Sports.