I have been observing my cat and found that when confronted with an unknown item, she will always use her front left paw to touch it.

This has me wondering if animals exhibit handedness like humans do? (and do I have a left handed cat?)

One note of importance is that with an unknown item, her approach is always identical, so possibly using the left paw means allowing a fast possible exit based on how she positions her body.

This question is related to Are there dextral/sinistral higher animals?. However, I question the "paw-ness" as a consequence of how the cat is approaching new items (to be ready to flee), whereas the other question remarks about the high number of "right-pawed" dogs and questions the influence of people for this preference.

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    $\begingroup$ It seems a shame to close this as a duplicate when theforestecologist's answer is excellent, and better than the answer on the other question. $\endgroup$ – Jack Aidley Mar 16 '17 at 16:24
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    $\begingroup$ If the questions are exact duplicates, a mod can merge them. On Stack Overflow (my home site) it's somewhat common to close older questions as duplicates of newer ones if the new one is better. (I haven't lurked here long enough to know the local custom.) $\endgroup$ – Jeffrey Bosboom Mar 17 '17 at 0:04

Short Answer

Yes. handedness (or Behavioral Lateralization) has been documented in numerous vertebrates (mammals, reptiles and birds) as well as invertebrates.

Long Answer

There have been numerous studies that have documented behavioral lateralization in many groups of animals including lower vertebrates (fish and amphibians), reptiles (even snakes!), birds and mammals. More recent work (e.g., Frasnelli 2013) has also shown that lateralization can also occur in invertebrates. In other words, "handedness" (or pawedness, footedness, eyedness, earedness, nostriledness, toothedness, breastedness, gonadedness, etc.) occurs rather extensively across the animal kingdom.

  • These studies suggest that the evolution of brain lateralization, often linked to lateralized behaviors, may have occurred early in evolutionary history and may not have been the result of multiple independent evolutionary events as once thought.

  • Although this view of brain lateralization as a highly conserved trait throughout evolutionary history has gained popularity, it's still contested (reviewed by Bisazza et al. 1998; Vallortigara et al. 1999).

Note: Laterality of function may manifest in terms of preference (frequency) or performance (proficiency), with the former being far more often investigated.

And no, right-handedness is not always dominant.

But Why?

  • One hypothesis is that brain lateralization was the evolutionary result of the need to break up complex tasks and perform them with highly specialized neuronal units to avoid functional overlap (i.e., to account for "functional incompatibility").

  • In humans, many hypotheses have been developed including: division of labor, genetics, epigenetic factors, prenatal hormone exposure, prenatal vestibular asymmetry, and even ultrasound exposure in the womb.

  • Snake studies (see below) have suggested lateralization behavior can be dictated by environmental conditions (specifically, temperature).

  • Other work (Hoso et al. 2007) suggest that lateralization could be the result of convergent evolution. In this case, snakes developed feeding aparati that allow them to better consume more-common dextral species of snails.

    • Note: dextral (meaning "clockwise") is a type of chirality -- another form of "handedness"


Some Examples:





  • Preferential use of right hemipenis over left under warm conditions. [Shine et al. 2000].

  • Coiling asymmetries were found at both the individual and population levels. [Roth 2003].



  • Pawdness in mice. [Collins 1975].

  • left forelimb bias in a species of bat when using hands for climbing/grasping. [Zucca et al. 2010]

  • Behavior experiments show domesticated cats show strong preference to consistently use either left or right paw and that the lateralized behavior was strongly sex related (in their population: ♂ = left / ♀ = right). [Wells & Millsopp 2009].

Non-human Primates

  • Posture, reaching preference, tool use, gathering food, carrying, and many other tasks. See McGrew & Marchant (1997) for review.


  • Ades, C., and Novaes Ramires, E. (2002). Asymmetry of leg use during prey handling in the spider Scytodes globula (Scytodidae). Journal of Insect Behavior 15: 563–570.

  • Bauer, R. H. (1993). Lateralization of neural control for vocalization by the frog (Rana pipiens). Psychobiology, 21, 243–248.

  • Bisazza, A., Cantalupo, C., Robins, A., Rogers, L. J. & Vallortigara, G. (1996). Right-pawedness in toads. Nature, 379, 408.

  • Bisazza, A., Rogers, L. J. & Vallortigara, G. (1998). The origins of cerebral asymmetry: a review of evidence of behavioural and brain lateralization in fishes, reptiles and amphibians. Neuroscience and Biobehavioral Reviews, 22, 411–426.

  • Bisazza, A., Lippolis, G. & Vallortigara, G. (2001). Lateralization of ventral fins use during object exploration in the blue gourami (Trichogaster trichopterus). Physiology & Behavior, 72, 575–578.

  • Bradshaw, J. L. & Rogers, L. J. (1993). The Evolution of Lateral Asymmetries, Language, Tool Use and Intellect. San Diego: Academic Press.

  • Byrne, R.A., Kuba, M. and Griebel, U. (2002). Lateral asymmetry of eye use in Octopus vulgaris. Animal Behaviour, 64(3):461-468.

  • Byrne, R.A., Kuba, M.J. and Meisel, D.V. (2004). Lateralized eye use in Octopus vulgaris shows antisymmetrical distribution. Animal Behaviour, 68(5):1107-1114.

  • Byrne, R.A., Kuba, M.J., Meisel, D.V., Griebel, U. and Mather, J.A. (2006). Does Octopus vulgaris have preferred arms?. Journal of Comparative Psychology 120(3):198.

  • Collins RL (1975) When left-handed mice live in righthanded worlds. Science 187:181–184.

  • Friedmann, H., & Davis, M. (1938). " Left-Handedness" in Parrots. The Auk, 55(3), 478-480.

  • Hoso, M., Asami, T., & Hori, M. (2007). Right-handed snakes: convergent evolution of asymmetry for functional specialization. Biology Letters, 3(2), 169-173.

  • McGrew, W. C., & Marchant, L. F. (1997). On the other hand: current issues in and meta‐analysis of the behavioral laterality of hand function in nonhuman primates. American Journal of Physical Anthropology, 104(S25), 201-232.

  • Robins, A., Lippolis, G., Bisazza, A., Vallortigara, G. & Rogers, L. J. (1998). Lateralized agonistic responses and hindlimb use in toads. Animal Behaviour, 56, 875–881.

  • Rogers, L. J. & Andrew, R. J. (Eds) (2002). Comparative Vertebrate Lateralization. Cambridge: Cambridge University Press.

  • Roth, E. D. (2003). ‘Handedness’ in snakes? Lateralization of coiling behaviour in a cottonmouth, Agkistrodon piscivorus leucostoma, population. Animal behaviour, 66(2), 337-341.

  • Shine, R., Olsson, M. M., LeMaster, M. P., Moore, I. T., & Mason, R. T. (2000). Are snakes right-handed? Asymmetry in hemipenis size and usage in gartersnakes (Thamnophis sirtalis). Behavioral Ecology, 11(4), 411-415.

  • Sovrano, V. A., Rainoldi, C., Bisazza, A. & Vallortigara, G. (1999). Roots of brain specializations: preferential left-eye use during mirror-image inspection in six species of teleost fish. Behavioural Brain Research, 106, 175–180.

  • Sovrano, V. A., Bisazza, A. & Vallortigara, G. (2001). Lateralization of response to social stimuli in fishes: a comparison between different methods and species. Physiology & Behavior, 74, 237– 244.

  • Vallortigara, G., Rogers, L. J., Bisazza, A., Lippolis, G. & Robins, A. (1998). Complementary right and left hemifield use for predatory and agonistic behaviour in toads. NeuroReport, 9, 3341–3344.

  • Vallortigara, G., Rogers, L. J. & Bisazza, A. (1999). Possible evolutionary origins of cognitive brain lateralization. Brain Research Reviews, 30, 164–175.

  • Wells, D. L., & Millsopp, S. (2009). Lateralized behaviour in the domestic cat, Felis silvestris catus. Animal Behaviour, 78(2), 537-541.

  • Zucca, P., Palladini, A., Baciadonna, L. and Scaravelli, D. (2010). Handedness in the echolocating Schreiber's long-fingered bat (Miniopterus schreibersii). Behavioural processes, 84(3): 693-695.

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    $\begingroup$ Holy c...bologna! That's a lot of citations, even for SE standards! $\endgroup$ – xDaizu Mar 17 '17 at 8:40
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    $\begingroup$ To add to the list: octopodes also have their preferred arm. $\endgroup$ – John Dvorak Mar 17 '17 at 14:40
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    $\begingroup$ Quick search suggests an article at nature.com, but its external links don't work. #2 is a paper at PubMed that I haven't bought. #4 looks promising but I didn't check the site it's published on, but it seems to be the same paper as #2 offers for purchase. ScienceDirect hosts a different paper as well as a video but they seem to be mostly about movement. $\endgroup$ – John Dvorak Mar 17 '17 at 15:49
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    $\begingroup$ Lateralization has also been shown in mother-infant interactions (left side of mother bias) in diverse mammal species, purportedly due to right brain hemisphere social processing Lateralization of mother–infant interactions in a diverse range of mammal species $\endgroup$ – nicfit Jan 22 '18 at 2:33
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    $\begingroup$ Horses also display handedness in their gaits: equine-rehab.com/handedness-in-horses Also, they show it in their manes, which naturally fall either to the left or right side of their neck. No idea whether that correlates to their gait, though. $\endgroup$ – jamesqf Jun 28 '19 at 18:04

Stanley Coren, The Lefthander Syndrome, says that humans are distinctive, not in having preferred handedness, but in having a high majority of individuals right-sided instead of odds approaching 50-50.

There is a lot of urban legend biology that might be answered. For instance, right-handedness is a human combat advantage, because a right-handed attack or defense puts the heart slightly further away from an opponent than an attack that's left-handed. And that one doesn't require a real knowledge of biology to answer: 48% of Olympic fencers are left-handed, and among people who've studied it left-handed people are far more likely to be excellent at combat sports than right-handed people.

(I'd love to see someone debunk the array of folk explanations for why a large majority of humans are right-handed.)

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    $\begingroup$ Maybe it also swayed that way because humans co-operate a lot: I am left handed and as an experiment, I decided for a couple weeks to do interactions, when buying items, etc, as a right handed; it was amazing how much smoother everything was, just hands meeting one another to exchange an item alone was noticeably more direct than me interacting as a lefty; with that, it is possible that babies start to go the more convenient path, reinforcing the right handed majority; I highly recommend that experiment, it’s simple, fun and interesting. $\endgroup$ – Thomas Mar 16 '17 at 21:18
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    $\begingroup$ If by answer you mean 'debunk', then this is consistent. Otherwise, you'd be saying that right-handed people have a combat advantage and left-handed people are better at combat sports, which wouldn't follow. I'm not sure which one it is. $\endgroup$ – person27 Mar 17 '17 at 5:26

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