PAW PREFERENCE IN CATS
Copyright 2012, Sarah Hartwell
Owners sometimes wonder if pet cats have a paw-preference in the same way that humans are left-handed, right-handed, or more rarely, ambidextrous. These owners may have noticed that their cats favour one or other forepaw when reaching for a toy or small object.
A 1991 study at Ataturk University in Turkey [Ref 6] found that 50 percent of cats were right-pawed, 40 percent were left-pawed and 10 percent showed no preference. In 1993, a French study [Ref 2] of 44 cats found that 17 were left-handed and 6 were right-handed when reaching towards a moving spot of light. The remaining cats showed no preference. Cats that did have paw preference reacted faster with their dominant paw than with their less-used paw.
In 1997, Pike and Maitland [Ref 4] studied pet catss reaching for a static food treat found 46% to be right-pawed, 44% were left-pawed and 10% were ambidextrous. 60% of the studied cats used their preferred paw 100% of the time over the 10 week study and there were no significant sex differences.
In a 2009 study, published in the journal Animal Behaviour [Ref 1] and reported in New Scientist, Dr Deborah L Wells and Sarah Millsopp of the School of Psychology, Queen's University, Belfast studied the paw-preference behaviour of 42 pet cats. They found that female cats tended to be right-pawed, while males had a strong tendency to be left-pawed when faced with complex or difficult tasks. However, for simple tasks, the cats would use either paw. In 2012, the same researchers [Ref 5] noted that paw-preference develops between 6 and 12 months old. This may be linked to hormones and sexual maturity. Burgess and Villablanca [Ref 14] had also noted that kittens at 6 to 8 weeks old had not developed paw-preference.
For humans, a simple task would be something like opening a door or batting away an irritating fly. Most of us use whichever hand is closest to the object, or whichever isn’t already performing another task (such as holding a cup of coffee or using the computer mouse). However, we prefer to use our dominant hand to perform more complex tasks such as writing. Some people are ambidextrous and equally adept at performing complex tasks with either hands. Others have learned to use the non-dominant hand for certain complex tasks, for example I learned to manipulate fiddly microscopes with my left hand so that my right hand remained free for note-taking ... and when writing on a blackboard, I can use either hand!
In humans, left handedness is more common in men than in women. “Handedness,” “paw preference”, “dominant side” and “lateralized behaviour” are the main terms used to describe the same thing.
PAW PREFERENCE ON SIMPLE TASKS
For simple games, such as grasping a toy mouse being dragged along on a string, the male and female cats showed equal preference for either paw. This would be why the French study [Ref 2], Pike and Maitland [Ref 4] and Tan and Kutlu [Ref 6] didn’t show a significant paw preference when the cats were performing the simple task of reaching for a moving spot of light or for a food treat.
If the mouse was suspended above the cats’ heads, they would use either paw and showed no preference.
PAW PREFERENCE ON COMPLEX OR DIFFICULT TASKS
One particularly difficult task presented to the cats in the study was a small jar containing a piece of tuna. All 21 female cats favoured their right paw. 20 of the 21 tom cats used their left paw exclusively while the remaining male appeared to be ambidextrous.
This was significant in showing that cats, like humans, are more skilled with one paw than the other. Although there was a 50/50 split between left and right paw preference, this split reflected a gender difference.
According to Dr Wells, "The more complex and challenging [the task], the more likely we're going to see true handedness,"
Like humans, cats have a forepaw that is more coordinated than the other, but this “handedness” is much less pronounced in cats than in humans. For simple tasks cats are more ambidextrous than humans, but when pushed to perform more complex tasks they use the more co-ordinated paw. But consider this – in the developed world, tools, utensils and appliances tend to be designed for right-handed people which reinforces our behaviour. The pronounced human “handedness” behaviour may also be conditioned during childhood to conform to cultural norms [Ref 17].
WHAT PERCENTAGE OF CATS ARE SOUTHPAWS?
The answer depends on which studies you read and whether the cats were performing simple or demanding tasks. The studies from the 1990s mostly used a simple food-reaching test which didn’t cause the cats to properly show paw preference.
In 1990, Tan, Yaprak and Kutlu found 51.5% to be right-handed, 36.4% to be left-handed, and 12.1% to be ambidextrous. 41.7% of the males were right-pawed, 50.5% were left-pawed, and 8.3% were ambidextrous. 52.4% of the females were right-pawed, 33.3% were left-pawed, and 14.3% were ambidextrous.
In 1991, Tan and Kutlu [Ref 6] found 49.5% of cats were right-handed, 40.4% were left-handed and 10.1% were ambidextrous. 54.0% of female cats were right-handed, 36.5% were left-handed, and 9.5% were ambidextrous. 43.5% of male cats were right-handed, 45.7% were left-handed, and 10.9% were ambidextrous.
In 1997, Pike and Maitland [Ref 4] found that 46% of cats studied were right-pawed, 44% were left-pawed and 10% were ambidextrous.
According to Augustus Brown’s children’s book of obscure facts about cats and dogs “Play it Again Tom” (Bantam Press, Oct 2007), for complicated tasks, 20% of cats are right-handed, 38% of cats are left-handed and 42% of cats are ambidextrous
The more recent studies using different types of test show the split of left to right paw preference is closer to 50/50. In comparison, around 10% of people favour their left hand, while 90% are right handed, but this is also influenced by cultural pressures.
The hormone testosterone has been shown to play a part in determining handedness. Greater prenatal testosterone exposure appears linked to left-handedness. In dogs, but not cats, neutering and spaying eliminated the gender bias.
TESTING YOUR CAT’S PAW PREFERENCE
Dr. Stefanie Schwartz offers a few simple tests you can use to determine your cat’s paw preference. You need to repeat the tests at least 100 times over several days and keep a note of the results. Other things can affect the results though; a cat with an injury might use its non-dominant paw.
FOOTNOTE FOR DOG-LOVERS
In case you’re wondering, a study at the University of Manchester, UK in 2006 found a similar gender-related split in dogs. In addition, dogs have a more pronounced “handedness” than cats and will use their dominant paw even if it’s injured. However, if your dog has been spayed or neutered, it will most likely lose paw preference. According to Dr. Stefanie Schwartz of the American College of Veterinary Behaviorists, studying right-brain and left-brain connections, genetics and sexual orientation may one day change the way dogs and cats are bred, raised, trained and used.
SUMMARY OF STUDIES
The study examined the paw use of 42 domestic cats on three tasks designed to determine whether the animals performed asymmetrical motor behaviour (“handedness”). The influence of the cats' sex and age on their paw preferences was also explored. Paw preference differed significantly between complex and simple tasks. Lateralized behaviour was found to be strongly sex related. The cats’ age was unrelated to either strength or direction of preferred paw use. There was a relationship between sex and handedness and also between task complexity and handedness. Lateralized behaviour was most evident on more complex manipulatory tasks, suggesting cats have functional brain specialization.
Paw-dominance was studied over a period of 6 years using 44 domestic cats trained to perform a reaching movement toward a moving spot of light. Both paw preference and paw performance were recorded. 23 cats had a significant preference for one paw. 17 were left-handed and 6 were right-handed. Lateralized cats (cats with a dominant paw) had faster reaction times than those that didn’t display paw dominance. The more-used paw had a shorter reaction time, a shorter movement time, and was more accurate than the less-used paw. This shows that there is an advantage to being lateralized.
9 unfortunate young male cats had their brains bisected so that the left and right hemispheres could not communicate with each other. While the cats didn’t have a dominant eye for sighting objects, they did have a dominant paw. Cats with strong paw preference resisted changing this even when the hemisphere controlling the paw was disconnected from the hemisphere receiving the visual cues (i.e. only one eye was allowed to see the object). This suggested a sub-cortical site of visual-motor integration. The cat’s resistance to change in paw preference when visual input is restricted to the “disconnected” hemisphere reflects the prominence of indirect (and apparent absence of direct) cortico-spinal connections with the final common path. This highlighted differences in cat brain anatomy and primate brain anatomy.
Unrestrained, untrained domestic cats (28 males and 20 females), living in a natural domestic environment, were studied for paw preferences using a food reaching test. 46% were right-pawed, 44% were left-pawed and 10% were ambidextrous. 60% of the studied cats used their preferred paw 100% of the time. (Left-handed cats: 15 male and 6 female. Right-handed cats: 11 male and 9 female. Ambidextrous (non-preferent) cats: 2 male and 5 female.) This preference was stable over the 10 week study and was not influenced by the presence of food residue on the cats' non-preferred paw. There was no difference between male and female cats in the proportions of left- and right-pawed individuals. In static food-reaching tests, domestic cats show a marked paw preference with an equal distribution of left- and right-pawed individuals and there were no significant sex differences. The authors noted that moving-target reaching tests indicated a preference for using the left paw.
This studied the development of paw preferences in cats. 12 cats were tested at ages 12 weeks, 6 months, and 1 year on a task where they had to use one or other paw to retrieve food. In case the cats learned behaviour specifically for the test, a separate set of 11 cats was tested at 6 months, while a third set of 14 cats was tested at 1 year old. At 12 weeks old and 6 months old, cats were much more likely to have no paw preference. By 1 year old their showed paw preference behaviour. Cats that had developed a paw preference at 6 months old still preferred the same paw at 1 year old. The lateralized behaviour was also strongly sex related. Females were mostly right-handed while males were significantly more inclined to be left-handed. Findings indicated that cats develop paw preferences by 1 year and suggest this preference remains stable thereafter. The strong sex difference in handedness strengthened the case for a biological mechanism influencing motor asymmetry in cats.
Paw preference in 109 cats was assessed using a food reaching test. 54 (49.5%) cats were found to be right-handed, 44 (40.4%) were left-handed and 11 (10.1%) were ambidextrous. In the 63 female cats studied, 34 cats (54.0%) were right-handed, 23 (36.5%) were left-handed, and 6 (9.5%) were ambidextrous. This study found right-handedness to be significantly higher than left-handedness in females; similar to humans. In the 46 male cats studied, 20 (43.5%) were right-handed, 21 (45.7%) were left-handed, and 5 (10.9%) were ambidextrous. The proportion of the strongly right-handed females (44%) was significantly higher than that of the strongly right-handed males (28%), again similar to humans. In right-handed cats, the incidence of moderate left-paw use was higher in males than in females. There was no significant difference in the proportions of strongly left-handed males and females. It was concluded that paw preference in cats is largely shaped by females and a prominent left-paw use of males. The right-biased paw preference in females compared to males suggested that females might be responsible for the emergence of cerebral lateralization and hand preference in animals and humans. It was tentatively suggested that a female right-shift factor might be required for the emergence of right-handedness; the absence of this factor would decrease the chance of being right-handed and increase the vulnerability of the developing brain to environmental influences instead.
The paw preference of 66 cats was assessed by a food-reaching test. Of the 66 cats, 34 (51.5%) were right-handed, 24 (36.4%) were left-handed, and 8 (12.1%) were ambidextrous. The study found evidence for an overall paw preference, general paw preference and for right-, and left-paw preference. Of the 24 male cats, 10 (41.7%) were right-pawed, 12 (50.5%) were left-pawed, and 2 (8.3%) ambidextrous. In the 42 female cats, 22 (52.4%) were right-pawed, 14 (33.3%) were left-pawed, and 6 (14.3%) were ambidextrous. Left-pawed males were more strongly left-pawed than right-pawed males were right-pawed. Right-pawed females were more strongly right-pawed than left-pawed females were left-pawed. The paw preferences remained consistent over time; no learning tendencies were established during testing periods. It was concluded that there is a right-bias in paw preference of cats, which is caused by the female right-paw preference under the influence of a biological factor.
The distribution of the right minus left (R - L) paw use and its relation to hemispheric weight was studied in mongrel and tortoiseshell cats. Paw preference was assessed by a food reaching test. All 9 males were left-pawed; the 13 females were predominantly right-pawed. There was an inverse relationship between the degree of left-paw preference and the right-brain weight in males (but no correlation with left-brain weight). In females, the right-pawedness decreased and the left-pawedness increased as the right- and left-brain weights increased. The relationships between brain-weight and pawedness exhibited sexual dimorphism suggesting that genetic and hormonal factors play an important role in emergence of motor asymmetry in cats.
Paw preference and performance were analyzed in 12 male adult cats learning a complex visuo-motor reaching task towards a moving target. A strong bias towards left paw use (80.7% of trials) was seen early in training. Only one of the cats was consistently right-pawed. After practice, a shift was observed towards right paw use and the proportion of trials that used the left paw fell to 71.4%. Two of the left pawed cats strongly modified their paw preference: one became exclusively right-pawed while the other became ambidextrous. It was found in later practice that the faster paw was preferred, regardless of whether the cat was originally left- or right-pawed. The results confirmed a bias towards left paw use in cats performing a complex reaching task, and showed that this bias was weakened by practice. The left hemisphere may have become more important as the task became a well routinized one.
The relationship between right- and left- brain weights was studied in adult cats whose paw dominance had been established. It was concluded that hormonal factors influencing the body weight (testosterone in males, oestrogen in females) appear to influence the asymmetrical brain development (which is related to paw-preference) in cats.
44 cats were trained to reach for a moving target; their paw performance and paw preference were investigated. 23 of the cats showed a distinct paw preference. 17 were left-pawed and 6 were right-pawed. Although their speed and accuracy were about the same, cats with a paw-preference had a faster reflex action in the tests. For the whole group of 44 cats, the more frequently used paw was significantly more accurate and faster to trigger than the less used paw. The cats displayed an asymmetry in paw preference that is associated with a performance asymmetry.
Asymmetry in the height of the right (R) and left (L) Sylvian end points (relative to brain weight) was studied in right- and left-pawed male and female cats. The results supported the generalization that a brain symmetrical in a given region has more combined cortex than a brain that is asymmetrical for this region, but only for right-handed cats (Galaburda et al., 1987).
The effect of lithium and imipramin on paw preference was studied in cats. Paw preference was assessed by the food-reaching test. It was found that lithium decreased, and imipramin increased the asymmetry of paw use. The lithium effect was antagonized by imipramin. Paw preference appears to reflect a biochemical asymmetry in the brain.
Paw preference can be changed by injury and rehabilitation. The study investigated how age was related to the recovery of motor functions after brain-damage. 9 newborn cats and 11 adult cats had the entire left hemisphere removed i.e. affecting motor functions on the right side. The newborn-lesioned animals showed no paw preference when they reached 5 to 8 weeks of age, but most later developed a long-term preference for the unimpaired left limb. The adult-lesioned cats showed a significantly greater left limb preference. Exercising the impaired limb, was effective in reversing the paw preference bias in all of the cats, but the adult-lesioned found it more difficult to master a food retrieval task with the impaired limb.
Hand or paw preferences are common among a variety of vertebrate species. Cats had to perform two standardized manual laterality tasks, differing in postural demand. 28 cats were forced to use either a stable or unstable body posture (i.e., sitting or standing vs. vertical clinging) to extract food items from a plastic box attached at two different heights. 40% of the cats were left-handed, 30% were right-handed and 30% were ambidextrous. There was no difference in paw-preference whether the body posture was stable or unstable.
There is a strong evidence that the dominance of language functions in the cerebral cortex differs between left-handed and right-handed people. Left-handedness tends to run in families i.e. there is a genetic factor. However, there also appear to be environmental and cultural factors involved. A polygenetic explanation which takes environmental influences into consideration is probably called for.
Agricultural societies show a significantly lower incidence of left-handedness than societies that depend on hunting. In agricultural societies, there was greater pressure for women to conform and become right-handed, to the point where no left-handed women were observed. There is no such pressure in hunting cultures and left-handed women occurred almost as frequently as left-handed men. This shows there may be cultural pressures to avoid left-handedness.