The most arboreal of the great apes, orangutans spend most of their time in trees. They have proportionally long arms and short legs and their hair is reddish-brown. Adult males may develop distinctive cheek pads or flanges and make long calls that attract females and intimidate rivals; younger males do not and resemble adult females. Orangutans are the most solitary of the great apes, social bonds occurring primarily between mothers and their dependent offspring, who remain together for the first two years. Fruit is the most important component of an orangutan's diet, but they will also eat vegetation, bark, honey, insects and bird eggs. They can live over 30 years both in the wild and in captivity.