Association between coat colour and the behaviour of Australian Labrador retrievers

Diane Van Rooy,Claire M Wade

doi:10.1186/s40575-019-0078-z

Abstract

BackgroundMaking assumptions regarding temperament and intelligence based on the physical appearance of dogs can be a conscious or unconscious human act. Labrador retrievers with chocolate-coloured coats are anecdotally considered to be less trainable and more hyperactive and aggressive than their black or yellow peers. To test these assertions, we analysed the owner-reported behavioural traits of Labradors in relation to both their observable coat colour, and their TYRP1 and MC1R genotypes.ResultsWe used the results of an owner-based questionnaire to determine scores for 21 behavioural traits and test whether these scores varied with coat colour (n = 225). Familiar dog aggression was the only trait that was found to vary significantly with coat colour (P = 0.013). Yellow Labradors had a higher score than chocolate Labradors, even when corrected for multiple testing (P = 0.021).We repeated the analyses for a subset of 63 Labradors with available genotyping data for the genes (MC1R and TYRP1) that are known to determine the primary coat colours in Labradors. Familiar dog aggression scores varied with both the observed coat colour and MC1R genotype. Dogs homozygous for MC1R recessive allele (with yellow coat colour) scored higher for familiar dog aggression than either black or chocolate Labradors. However, no association maintained significance when incorporating Bonferroni correction. Dog trainability scores decreased additively as the number of recessive brown alleles for TYRP1 increased. This allelic association was independent of the observable coat colour. Dogs homozygous for the brown allele were considered less trainable than dogs with no brown alleles (P = 0.030).ConclusionsOur results do not support that chocolate-coloured Labradors are more hyperactive or aggressive than either black or yellow Labradors. Trainability scores varied with TYRP1 genotype but not the observable coat colour. Further validation is required.

Highlights

Making assumptions regarding temperament and intelligence based on the physical appearance of dogs can be a conscious or unconscious human act
There is little scientific data to support these beliefs. To put it to the test, we used chocolate, yellow or black Labradors exhibiting a range of behavioural characteristics as reported in an owner-based questionnaire
For each of 21 behavioural traits listed in Table 1, dogs of different coat colours were compared

Summary

Introduction

Making assumptions regarding temperament and intelligence based on the physical appearance of dogs can be a conscious or unconscious human act. Labrador retrievers with chocolate-coloured coats are anecdotally considered to be less trainable and more hyperactive and aggressive than their black or yellow peers. To test these assertions, we analysed the owner-reported behavioural traits of Labradors in relation to both their observable coat colour, and their TYRP1 and MC1R genotypes. Chocolate-coloured Labradors have a reputation for being less trainable and more hyperactive and aggressive than their black or yellow peers. Dogs with yellow coat colour are assessed as being more agreeable, conscientious and emotionally stable than dogs that are otherwise identical other than having a black coat [4]. Dogs with floppy ears are considered to be more agreeable and emotionally stable than dogs with pointy ears [4]

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