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eastern grey kangaroo (macropus giganteus)

social spacing

        Kangaroos are home range species (Dawson, 1995).  This comes as no surprise upon looking at the habitat they inhabit in Australia.  According to Dawson the eastern grey tends to inhabit wetter parts of the continent, but is the most widespread of the kangaroo species.  It is found in down the east coast Australia, which ranges from tropical in the north to drier lands in the south.  This suggests that they have an ability to adapt to different conditions, a factor that would suit their home-range nature.  They have been found to inhabit coastal areas, woodlands, sub-tropical forests, mountain forests, and inland scrubs (Firth & Calaby, 1969).  Since their diets consist almost entirely of grasses and shrubs, it would be impossible to occupy a classical territory and defend a resource such as grass (Firth & Calaby, 1969).  The main determinants of home range choice seem to be food availability and environmental changes.

Picture courtesy of The San Francisco Zoo

        Although they occupy a home range, Dawson writes that the grey kangaroo is mainly a sedentary species.  According to observational studies conducted by Dawson and colleagues they determined that during foraging males tend to travel larger distances than females.  This could be due to a number of factors.  Females - especially mothers - form the stable core of most aggregations.  They also have to very strong bond with their offspring (Dawson, 1995).  Another reason deals more with the physiological aspects of males and females.  Males can weigh on average twice as much as females as a result of the high level of sexual dimorphism in the eastern grey (Dawson, 1995).  As a result they may be less susceptible to predation pressure and more willing to forage further by themselves.  Like most other kangaroo species the eastern grey is mainly nocturnal.  However, Dawson also explains that this species of kangaroo has also been characterized as crepuscular.  This indicates that they are most active in the early morning and in the evening - with the lowest level of activity being during the day.  With their type of locomotion (hopping, quadrupedal, or pentapedal walking) it is of utmost importance to conserve energy.  With temperatures generally peaking during the day, it makes sense that these coincide with their lowest  level of activity.  A study by Moore, Coulson, and Way supports this idea.  They conducted a study in which they looked at patterns of habitat selection in kangaroos.  One of their findings was that eastern grey kangaroos tend to graze at a lower intensity throughout the day (Moore, Coulson, & Way, 2002).  The researchers also found that grassy clearings were selected for at a high frequency by individuals. 

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