Kangaroos, as marsupials, carry their young in a pouch.  
Far more convenient than the strollers used by humans.
The baby Kangaroo, called a joey, gets a great
view, plus mother's milk from nipples in the pouch.
Even after the youngster grows too large for
the pouch, it remains the source for nursing.
Australia has about 65 different species of Kangaroos,
in all sizes.  This is a Rock Wallabee, quite small and
unable to resist oatmeal.  The two pouch photos at the
top of this page are of Rock Wallabees.
Another small member of the Kangaroo family
is this Pademelon.
If you have a high speed internet
connection,  watch the Intrepid Berkeley
Explorer's free video of this trip by clicking
Kangaroo From Kakadu