Brief reminder of Part 1 (without mistake ) : Gorillas live in tropical and subtropical forests . They have a life expectancy of 30 years in the wild and 50 in captivity . The patriarch , known as the ' silverback ' is responsible for organising the group . He is prepared to give his life to defend his fellow creatures . There is no breeding season . Females reach sexual maturitie at around seven years of age . After a gestation period of 250 to 270 days , a baby is born weiging 1-2 kg and walking very quikly at around 6 months . The mother will have a baby every four years , which she will raise for 3 years . Once a female has procreated within a group , she stays there until she dies . Gorillas feed mainly on plants : berries , different types of shouts , stems , leaves , tree bark , which they strip off with their hands , and sometimes insectes (termites , ants ) . They do not drink water , contenting themselves with the water contain in their food to meet their needs . The group walks up to 5 km all day to find its subtenance . The gorilla is a mainly herbivoreus animal . The gorilla has a large stomach . This enables it to swallow an enormous quantity of food with a fibrous component (30 kg for males and 18 kg for females ) and therefore to maintain a high energy level . As they move around , ingesting large quantities of seed and throwing them back into forest gaps , gorillas help to regenerate the forests . Around 6 pm , the dominant male looks for a place for its family . Gorillas sleep in nests that they make themselves from plants . Each nest is only used once , as gorillas are nomads and are constantly on the move . Sleeping positions difer according to age and size ; adult gorillas generally sleep on their side or stomach , while babies nap on their mother ' s back .
