Limb preferences in non-human vertebrates

Abstract

There is considerable debate about whether population-level asymmetries in limb preferences are uniquely human or are a common feature among vertebrates. In the present article the results of studies investigating limb preferences in all non-extinct vertebrate orders are systematically analysed by employing cladographic comparisons. These studies analysed 119 different species, with 61 (51.26%) showing evidence for population-level asymmetries, 20 (16.81%) showing evidence for individual-level asymmetries and 38 (31.93%) showing no evidence for asymmetry. The cladographic comparison revealed that research in several key taxa in particular (e.g., Chondrichtyes, Crocodylia, Atlantogenata and Palaeognathae) would have important implications for our understanding of the evolution of vertebrate limb preferences. Furthermore, the findings of the present study support the position that population-level asymmetries in limb preferences as such represent a common vertebrate feature. Looking into the details, however, some important differences from human handedness become visible: Non-human limb preferences typically show a less-skewed lateralisation pattern and there are larger numbers of individuals without a preference in most species compared to humans. Moreover, limb preferences in non-human animals are often less task-invariant than human handedness and are more frequently modulated by external factors and individual characteristics.

Context-dependent lateralization of trunk movements in wild Asian elephants

“…one-sided bias in a group of subjects) forelimb preferences to species highly lateralized at both individual and population levels. At least a half of all studied species have been found to have left-or right-forelimb preference at the population level (Ströckens et al, 2013). In mammalian taxa, wild black bears, Ursus americanus, for instance, have been shown to use the right forelimb more often than the left one when scavenging (Reimchen and Spoljaric, 2011).…”

“…The majority of studies on motor lateralization in animals have been focused on the use of paired limbs (Ströckens et al, 2013). Meanwhile, the movements of unpaired appendages, such as the tail, can also be lateralized as shown for primates (Laska and Tutsch, 2000;Hanbury et al, 2010), rats (Denenberg and Yutzey, 1985;Afonso et al, 1993), and dogs (Quaranta et al, 2007).…”

“…Asian elephants, Elephas maximus, were examined both in captivity (Haakonsson and Semple, 2009) and in the wild (in Sri Lanka: Martin and Niemitz, 2003;in India: Keerthipriya et al, 2015), while a female African elephant, Loxodonta cyclotis, was observed in the zoo (Racine, 1980). In contrast to humans (Perelle & Ehrman 1994), great apes (Meguerditchian et al, 2013), bipedal marsupials (Giljov et al, 2015), parrots (Harris, 1989), anuran amphibians (Malashichev, 2006) and many other vertebrates (Ströckens et al,2013), elephants showed no population-level side biases in their manipulative behaviours neither with the use of the trunk nor with the use of the forelimbs (Haakonsson and Semple, 2009;Martin and Niemitz, 2003;Keerthipriya et al, 2015). However, taking into account that manifestation of motor lateralization depends on the nature of the task (Rogers, 2009), the full understanding of the lateralized trunk use in elephants cannot be gained without investigating it in different behavioural contexts.…”

“…Previously believed to be unique to humans, lateralized motor functions are currently considered to be a pervasive mammalian characteristic (Hook, 2004;Rogers, 2009;Rogers and Vallortigara, 2017). Lateralization of limb use has been investigated in a wide range of vertebrate species (reviewed in Ströckens et al, 2013). Vertebrates appear to show a significant variation in the degree of lateralization, ranging from species showing neither individual (i.e.…”

Effect of Weighted Hand Movements on Hand Function in Chronic Stroke Patients

“…The right hemisphere is more focused on the perception of whole and spatial tasks. Person with left hemisphere were also able to make less use of sensory information to update and modify the direction of the movement than persons with right hemisphere damage because the left hemisphere is responsible for motor programming [13][14][15].…”