Gorillas are social animals with many similarities to humans. When threatened, a male leader may attempt to protect his group through aggressive displays which commonly involve chest-beating or short rushes toward the danger. However, studies indicate that gorillas are normally quiet, even shy, animals that live in stable family groups. In zoos this shyness sometimes develops into inactivity or depression. Some zookeepers in Russia therefore have come up with a plan to give gorillas a broader experience of life by showing them wildlife videos. Although watching TV or videos is sometimes said to be harmful to human beings, the keepers think that this plan might make gorillas "think more about life."