Can Dogs And Cats Be Left-Handed?
Humans handedness is influenced by hundreds of genes and environmental factors. That being said, a consistent 10 percent of the human population is left-hand dominant… so there's definitely a big genetic component. A study in PLOS Genetics identified a gene, PCSK6, which helps determine how the body organizes itself in early development, and correlated it with hand-dominance. But, if handedness is genetic, shouldn't we see it throughout the rest of the natural world too? Well, it is seen in some animals! Great apes have handedness, for example; it has been detailed in studies published in Behavioural Brain Research and Animal Cognition. Scientists have theorized one of the influencing factors of hand dominance is rooted in the language processing part of the brain, but it could also have been passed down by our ancestors, thanks to our use of tools. The studies on great apes found they used different hands for different activities!
They preferred their right-hand for inanimate targets like sticks or toys, but for grooming they didn't report any dominance at all! Researchers believe this may be due to which hemisphere of the brain is being used. Grooming is emotional and social, while grabbing sticks is purely functional. This functional preference for hands has been observed in other primates too! Seventy percent of chimps are right-handed for functional tasks like manipulating a tool, or hilariously, which hand they choose when they throw feces at the researchers… MRI scans again showed it was probably due to brain hemispheres! Evolutionarily, scientists believe this preference for one hand may have appeared even before chimps and humans split from their common ancestor, as the scans showed similar structures to our own brains. Some enterprising researchers found similar brain structures toward handedness exist in cats, but with a twist: they're sex specific! When cats went to play with toys or remove food from jars, they found females preferred to use their right-paw, while males went left! Cat brains have this weird specialization too! Dogs on the other paw, don't seem to have this brain specialization. A 2006 study in Behavioural Processes found no population-level preference for a dominant hand, but that it might just be split 50-50. Scientists haven't just studied our fur-babies though. Kangaroos were discovered to be hand-specific (weirdly, most of them are lefties), and frogs were found prefer their right foot for some tasks.
Fish prefer one eye to the other when spotting predators! And even some birds, like chickens and pigeons, have brain-level hemisphere specializations for some visual tasks. But overall, quadruped animals aren't often studied for handedness -- one because they don't have hands, but two, because they're usually walking on all of their limbs. That's obviously a weird thing to think about, but handedness is kind of weird anyway. Even though we've identified some genes involved, geneticists don't agree on the exact process of how it happens. So we don't really know where it comes from! It just… is! And overall, as usual... more research is needed. I love that. We can't do episodes like this without our sponsors. If you listen to music and podcasts and are looking for a new Bluetooth speaker, check out Monster's reimagined boombox, the Monster Blaster. It's available for monthly payments starting at $25. The Monster Blaster has the power to bring music to life indoors and out.
They preferred their right-hand for inanimate targets like sticks or toys, but for grooming they didn't report any dominance at all! Researchers believe this may be due to which hemisphere of the brain is being used. Grooming is emotional and social, while grabbing sticks is purely functional. This functional preference for hands has been observed in other primates too! Seventy percent of chimps are right-handed for functional tasks like manipulating a tool, or hilariously, which hand they choose when they throw feces at the researchers… MRI scans again showed it was probably due to brain hemispheres! Evolutionarily, scientists believe this preference for one hand may have appeared even before chimps and humans split from their common ancestor, as the scans showed similar structures to our own brains. Some enterprising researchers found similar brain structures toward handedness exist in cats, but with a twist: they're sex specific! When cats went to play with toys or remove food from jars, they found females preferred to use their right-paw, while males went left! Cat brains have this weird specialization too! Dogs on the other paw, don't seem to have this brain specialization. A 2006 study in Behavioural Processes found no population-level preference for a dominant hand, but that it might just be split 50-50. Scientists haven't just studied our fur-babies though. Kangaroos were discovered to be hand-specific (weirdly, most of them are lefties), and frogs were found prefer their right foot for some tasks.
Fish prefer one eye to the other when spotting predators! And even some birds, like chickens and pigeons, have brain-level hemisphere specializations for some visual tasks. But overall, quadruped animals aren't often studied for handedness -- one because they don't have hands, but two, because they're usually walking on all of their limbs. That's obviously a weird thing to think about, but handedness is kind of weird anyway. Even though we've identified some genes involved, geneticists don't agree on the exact process of how it happens. So we don't really know where it comes from! It just… is! And overall, as usual... more research is needed. I love that. We can't do episodes like this without our sponsors. If you listen to music and podcasts and are looking for a new Bluetooth speaker, check out Monster's reimagined boombox, the Monster Blaster. It's available for monthly payments starting at $25. The Monster Blaster has the power to bring music to life indoors and out.
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