A team of researchers led by Russian biologist Yegor Malashichev has published a paper in the Current Biology journal which claims that, after extensive observation of kangaroos, it found out that the marsupials present signs of true-handedness and have a preference for their left hand.
Malashicev’s team observed the kangaroos in the wild through locations in Australia and Tasmania, and found that kangaroos prefer to use their left hand to do select actions such as picking leafs and grooming their nose, a preference mostly observed in red and eastern grey ones. Red-neck wallabies are the only types who use different hands for different functions: they tend to use their left hands for actions that require finesse and right hands for what requires strength.
The finding is peculiar when considering the fact that it is mostly thought kangaroos do not possess handedness; that is because their brain does not have the connections between their left and right hemispheres which are linked to handedness in primates. However, the fact that kangaroos are bipedal might be a decisive factor in their unique trait amongst non-primates.
The end result showing that kangaroos are mainly left handed gets even more ambiguous when considering the fact that certain types of kangaroos don’t show signs of handedness at all. This includes both wild kangaroos that stay more in trees and captive kangaroos as well.
Handedness was considered to be an uniquely human trait for a long time, later evidence reclassifying it as a primate trait. However, in the last years more evidence has surfaced which shows that some mammal types – such as some marsupials – showed signs of handedness. This research is the most comprehensive and decisive in this regard to date, though it is unlikely to stop the ongoing dispute in the scientific world about non-primate handedness.
Research on handedness in wild animals has been scarce until now due to its high difficulty, and so most critics of the notion have pointed out that such traits might have been picked up by captive animals from human keepers. But observations made on wild chimpanzee populations have shown that they have certain hand preferences for different tasks.
One particular observation during this research might prove to be key here: red-necked wallabies showed no bias towards any of their hand while feeding down on an all four posture. This could ultimately prove that handedness is actually tied to posture rather other factors, as ultimately the hands are freed up in bipeds for a vast array of activities.
Image Source: Sentinel Republic