 The impala is diurnal ( active mainly during the day ) , though activity tends to cease during the hot midday hours ; they feed and rest at night . Three distinct social groups can be observed – the territorial males , bachelor herds and female herds . The territorial males hold territories where they may form harems of females ; territories are demarcated with urine and faeces and defended against juvenile or male intruders . Bachelor herds tend to be small , with less than 30 members . Individuals maintain distances of 2 @.@ 5 – 3 metres ( 8 @.@ 2 – 9 @.@ 8 ft ) from one another ; while young and old males may interact , middle @-@ aged males generally avoid one another . The membership of female herds varies from 6 to 100 ; herds occupy home ranges of 80 – 180 hectares ( 200 – 440 acres ; 0 @.@ 31 – 0 @.@ 69 sq mi ) . The mother @-@ calf bond is weak , and breaks soon after weaning ; juveniles leave the herds of their mothers to join other herds . Female herds tend to be loose and have no distinct leadership . Allogrooming is an important means of social interaction in bachelor and female herds ; in fact , the impala appears to be the only ungulate to display self @-@ grooming as well as allogrooming . In allogrooming , females typically groom related individuals , while males associate with unrelated individuals . Each partner grooms the other six to twelve times . 
