Boys are right-handed, girls are left...

Mar 05, 2013
Many animals show a distinct preference for using one hand/paw/hoof over another. Credit: Andrey Giljov, Karina Karenina and Yegor Malashichev

Well at least this is true for sugar gliders (Petaurus breviceps) and grey short-tailed opossums (Monodelphis domestica), finds an article in BioMed Central's open access journal BMC Evolutionary Biology, and 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 show less hand preference than toddlers.

Some species also show a distinct sex effect in handedness but among non-marsupial mammals this tendency is for left-handed males and right-handed females. In contrast researchers from St Petersburg State University show that male quadruped marsupials, such as who walk on all fours, tend to be right-handed while the females are left-handed, especially as tasks became more difficult.

Dr Yegor Malashichev from Saint Petersburg State University who led this study explained why they think this has evolved, "Marsupials do not have a corpus callosum – which connects the two halves of the mammalian brain together. Reversed sex related handedness is an indication of how the marsupial brain has developed different ways of the two halves of the brain communicating in the absence of the corpus callosum."

Explore further: A molecular compass for bird navigation

More information: Forelimb preferences in quadrupedal marsupials and there implications for laterality evolution in mammals, Andrey Giljov, Karina Karenina and Yegor Malashichev, BMC Evolutionary Biology (in press)

add to favorites email to friend print save as pdf

Related Stories

Discounting the 'lefty' myth

Jun 07, 2011

(Medical Xpress) -- Left-handed people consistently perform worse than right-handed people in measures of cognitive ability, or IQ, with the ‘level of disability’ equivalent to being prematurely born.

Recommended for you

A molecular compass for bird navigation

12 minutes ago

Each year, the Arctic Tern travels over 40,000 miles, migrating nearly from pole to pole and back again. Other birds make similar (though shorter) journeys in search of warmer climes. How do these birds manage ...

100,000 bird samples online

2 hours ago

The Natural History Museum (NHM) in Oslo has a bird collection of international size. It is now available online.

New genetic technologies offer hope for white rhino

3 hours ago

With support from the Seaver Institute, geneticists at San Diego Zoo Institute for Conservation Research are taking the initial steps in an effort to use cryopreserved cells to bring back the northern white rhino from the ...

Cats put sight over smell in finding food

19 hours ago

Cats may prefer to use their eyes rather than follow their nose when it comes to finding the location of food, according to new research by leading animal behaviourists.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.