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Right-handed or left-handed? Kangaroos actually have a preference

Primate mammals aren't the only species with hand preferences. A study shows that kangaroos mostly prefer using their left paws over their right when it comes to eating, grooming and possibly boxing.

If you ever get into a fist fight with a kangaroo, watch out because it's probably got a mean left. Also, stop challenging animals to fist fights.Wikimedia

We cocky humans think we've got it all: opposable thumbs, a talent for using acronyms as whole sayings in spoken conversations and the ability to create machines that make ice cream and Xbox Ones.

Some of us may have even assumed that our preference for using one hand over the other is unique to our species and our primate ancestors. Well, get ready to feel like we've dropped another rung in the species dominion race, because hand preferences apparently aren't unique to primate mammals.

The journal Cell Biology published a study Thursday that found that wild kangaroos and other marsupials actually have a hand preference when it comes to everyday tasks -- and most would rather use their left one.

Researchers didn't expect to find "handedness" in kangaroos, as the brains of kangaroos and other marsupials don't have the same neural connections between the left and right hemispheres as species like primates and humans for which hand preference is common. This latest discovery seems to contradict that belief and could lead to a better understanding of the marsupial mind.

The research comes from biology professor Yegor Malashichev of St. Petersburg State University in Russia. He's been studying and observing hand preferences in animal behavior for quite awhile.

He first observed this behavior in amphibians back in 2002 in the American Psychology Association's Journal of Comparative Psychology and conjectured that this preference for one limb over the other "may be applicable to other vertebrates possessing paired appendages," according to the study's abstract.

Malashichev's latest study reported that "according to a special-assessment scale of handedness adopted for primates, kangaroos pulled down the highest grades," according to a release. Specifically, he observed that eastern gray and red kangaroos in parts of Tasmania and continental Australia favor the left hand when it comes to daily routine tasks such as eating, picking leaves and grooming.

The study observed similar behavior in other marsupials such as the red-necked wallaby.

Thanks to this and other recent studies, this is just the latest animal behavior we previously thought was only relegated to humans. Two separate studies released in the last two weeks revealed that wild chimpanzees enjoy drinking alcoholic beverages and prefer eating cooked food.

What's next? Do pythons prefer to drive themselves rather than ride in someone else's car because it makes them car sick? Are elephants more likely to "swipe right" when they see mates with longer trunks? Do jellyfish prefer food that's gluten-free?