Mar. 6, 2013 Boys are right-handed, girls are left ... Well at
least this is true for sugar gliders (Petaurus breviceps) and
grey short-tailed opossums (Monodelphis domestica), according to
an article in BioMed Central’s open access journal BMC
Evolutionary Biology that shows that handedness in marsupials is
dependent on gender. This preference of one hand over another
has developed despite the absence of a corpus collosum, the part
of the brain which in placental mammals allows one half of the
brain to communicate with the other. Many animals show a
distinct preference for using one hand/paw/hoof over another.
This is often related to posture – an animal is more likely to
show manual laterality if it is upright, related to the
difficulty of the task, more complex tasks show a handed
preference, or even with age. As an example of all three:
crawling human babies show less hand preference than toddlers.
Some species also show a distinct sex effect in handedness but
among non-marsupial mammals this tendency is