Kangaroos are born at a very early stage of nervous system development, compared to other mammals. After 33 days in the womb, newborns are only able to breath and suck, and their muscular ability is only enough to allow them to climb from the site of birth to the teat, inside the pouch, where they will stay for about six months.
Kangaroos and other marsupials have a very distinct brain microcirculation, which refers to the small vessels that irrigate the organ. While in most mammals numerous capillary vessels connect in the brains forming a mesh-work, in kangaroos this connections occur in pairs, forming loops. This evolutionary feature has been related to the kangaroo's ability to survive in Australia's hot and arid zones.
The corpus callosum is a bundle of nervous fibers that connect the right and left brain hemispheres of most mammals. However, kangaroos and other marsupials do not have such brain structure. To connect their brain hemispheres, kangaroos have a similar nervous structure called fasciculus aberrans. Connection between the hemispheres of the brain is related to eye sight in all mammals, including kangaroos.
The kangaroo's accurate vision and hearing is related to its early brain development. Some species, such as the red kangaroo, have nocturnal habits and an exceptional night vision. In addition to a well-developed cochlear or auditory nerve, which links kangaroos' internal ears to the brain, the animals can also rotate their ears, helping them to perceive the direction of the sound.