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Behavioural differences and similarities between dog breeds: proposing an ecologically valid approach for canine behavioural research

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The behaviour of dogs holds great relevance for not only scientists from fundamental and applied research areas, but also due to the widespread roles of dogs in our societies as companions and working animals; their behaviour is also an important factor in animal and human welfare. A large proportion of dogs currently under human supervision belong to one of roughly 400 recognised breeds. Dog breeds can be characterised by distinctive, predictable and reproducible features, including some of their behavioural traits. To the scientist, the comparative analysis of the behaviour of dog breeds provides an opportunity for investigating an array of intriguing phenomena within an easily accessible model organism created from natural and human‐driven evolutionary processes. There are many ways to design and conduct breed‐related behavioural investigations, but such endeavours should always be based around biologically relevant research questions and lead to ecologically valid conclusions. In this review, we surveyed recent research efforts that included dog behaviour‐related comparisons and applied a critical evaluation according to their methods of breed choice and the subsequent research design. Our aim was to assess whether these two fundamentally important components of experimental design provide a solid basis to reach valid conclusions. Based on 97 publications that fulfilled our selection criteria, we identified three primary methods used by researchers to select breeds for their investigations: ( i ) convenience sampling; ( ii ) hypothesis‐driven, ancestry‐based sampling; and ( iii ) hypothesis‐driven, functional sampling. By using the SWOT (Strengths, Weaknesses, Opportunities, Threats) evaluation system, we highlight each of these techniques' merits and shortcomings. We identify when particular methods may be inherently unable to produce biologically meaningful results due to a mismatch between breed choice and the initial research goals. We hope that our evaluation will help researchers adopt best practices in experimental design regarding future dog breed comparisons.
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Behavioural differences and similarities
between dog breeds: proposing an ecologically
valid approach for canine behavioural research
Péter Pongracz*and Petra Dobos
Department of Ethology, ELTE Eötvös Lorand University, 1117 Pazmany Péter sétany 1/c, Budapest, Hungary
ABSTRACT
The behaviour of dogs holds great relevance for not only scientists from fundamental and applied research areas, but also
due to the widespread roles of dogs in our societies as companions and working animals; their behaviour is also an impor-
tant factor in animal and human welfare. A large proportion of dogs currently under human supervision belong to one of
roughly 400 recognised breeds. Dog breeds can be characterised by distinctive, predictable and reproducible features,
including some of their behavioural traits. To the scientist, the comparative analysis of the behaviour of dog breeds pro-
vides an opportunity for investigating an array of intriguing phenomena within an easily accessible model organism cre-
ated from natural and human-driven evolutionary processes. There are many ways to design and conduct breed-related
behavioural investigations, but such endeavours should always be based around biologically relevant research questions
and lead to ecologically valid conclusions. In this review, we surveyed recent research efforts that included dog
behaviour-related comparisons and applied a critical evaluation according to their methods of breed choice and the sub-
sequent research design. Our aim was to assess whether these two fundamentally important components of experimental
design provide a solid basis to reach valid conclusions. Based on 97 publications that fullled our selection criteria, we
identied three primary methods used by researchers to select breeds for their investigations: (i) convenience sampling;
(ii) hypothesis-driven, ancestry-based sampling; and (iii) hypothesis-driven, functional sampling. By using the SWOT
(Strengths, Weaknesses, Opportunities, Threats) evaluation system, we highlight each of these techniquesmerits and
shortcomings. We identify when particular methods may be inherently unable to produce biologically meaningful results
due to a mismatch between breed choice and the initial research goals. We hope that our evaluation will help researchers
adopt best practices in experimental design regarding future dog breed comparisons.
Key words: dog breeds, behaviour, ecological validity, sampling technique, functional breed selection, popular breeds.
CONTENTS
I. Introduction ........................................................................69
II. Methods: literature survey ..............................................................70
III. Results of the literature analysis .........................................................70
IV. Critical evaluation of study design in dog breed-related behavioural research ......................70
(1) Convenience sampling of breeds caveats and advantages ................................ 70
(2) Planned breed choice ............................................................. 72
(3) Is there any way to create ecologically valid multi-breed comparisons? ....................... 73
(4) Can ancestry provide a biologically relevant basis for breed-related behavioural comparisons? .... 75
(5) Dog breed comparisons in light of applied ethology ..................................... 76
(a) Problematic behaviours ....................................................... 76
(b) Working dogs ............................................................... 77
(c) Interacting with dogs ......................................................... 77
*Author for correspondence (Tel.: +3630-262-1284; E-mail: peter.pongracz@ttk.elte.hu).
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in
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Biol. Rev. (2025), 100, pp. 6884. 68
doi: 10.1111/brv.13128
V. Discussion and SWOT analysis ..........................................................78
VI. Conclusions .........................................................................80
VII. Acknowledgements ...................................................................80
VIII. References ..........................................................................81
I. INTRODUCTION
The dog (Canis familiaris) is the oldest domesticated species
(e.g. Lee et al., 2015), cohabits with humans in every culture,
and according to some estimations, has reached nearly a
staggering one billion individuals worldwide (Coppinger &
Coppinger, 2021). Especially in countries of the global
North, people consider dogs as primarily fullling the role
of companions for humans (Meyer et al., 2022; Pongracz &
Dobos, 2023), and to a lesser extent, as a working animal (mil-
itary and police dogs, assistance dogs, herding and hunting dogs,
etc.). However, the largest proportion of the global dog popula-
tion exists as unowned individuals living in the cities and villages
of Southeast Asia, Africa and Central and South America
(Coppinger & Coppinger, 2021), where they are mainly known
as pariah (Oppenheimer & Oppenheimer, 1975), village
(Pendleton et al., 2018) or street dogs (Reece, Chawla &
Hiby, 2013). The common shared feature of these unowned
dogs is their reliance on human resources and unrestricted
reproduction (Boitani, Ciucci & Ortolani, 2007). Additionally,
these dogs show remarkable similarity across populations,
implying that their appearance and behaviour has been
shaped by natural selection (Coppinger & Coppinger, 2021).
Compared to unowned canines, dogs that live as compan-
ions or working animals show considerable variability, to the
extent that the dog can be considered as the most variable
mammalian species (Creevy et al., 2022). For example, there
is a roughly 50-fold difference in body mass between the
smallest and largest dog breeds. While there is a relatively
restricted set of genes responsible for the main features differ-
entiating the appearance of dogs [i.e. size, limb and tail
length, ear shape and position, fur length and texture, colour
(Ostrander, 2007; Wayne & VonHoldt, 2012)], alongside the
countless variations of mongrels, there are at least 400 differ-
ent dog breeds that are recognised by various organisations
(kennel clubs) across the world. Although dog breed
descriptions (standards) mainly emphasise physical appear-
ance, they usually also enumerate the original (working)
function and typical behaviour of the given breed. Behaviour
(working purpose) also serves as the main organising factor
behind the breed groupsof the various breeding organisa-
tions [e.g. FCI (Fédération Cynologique Internationale)
https://www.fci.be/en/Nomenclature/; AKC (American
Kennel Club) https://www.akc.org/dog-breeds/].
The behaviour of dogs has received increasing interest
from ethologists and comparative psychologists since the
1990s (Aria et al., 2021). A species that formerly was largely
ignored by ethologists because of doubts regarding its natu-
ralform (i.e. free from the effects of domestication) became
of interest when it was realised that the natural habitat for
dogs was the anthropogenic niche (Miklosi & Topal, 2013).
The evolutionary processes and the resulting socio-cognitive
features that helped dogs adapt so well to the human social
environment thus attracted both behavioural scientists and
comparative psychologists (Topal et al., 2009). In parallel,
the complex system of interactions between companion ani-
mals and their owners provided research opportunities for
applied ethologists (Pongracz & Dobos, 2023), particularly
as doghuman interactions are considered important aspects
of welfare for both parties (e.g. Glenk, 2017; Thielke &
Udell, 2019). Dog behaviour phenotypes proved to be
important in studies of evolution/domestication (e.g. in com-
parative investigations of the behaviour of tame wolves and
dogs; Gacsi et al., 2005), doghuman interactions (McGreevy
et al., 2012), cognitive ethology (e.g. understanding of projected
images; Péter, Miklosi & Pongracz, 2013), and various aspects
of applied behavioural sciences, such as training/selecting dogs
for working tasks (Bray et al., 2021), animal welfare issues
(e.g. behavioural signs of separation-related problems; Pongracz
et al., 2017), and human safety (e.g. behavioural assessments at
dog shelters; Mornement et al., 2010).
Breed-related differences in dog behaviour were investi-
gated even before dogs became a focus of scientists studying
humananimal interactions and domestication [e.g. the early
experiments of Scott & Fuller (1974) regarding the sensitive
period for early socialisation; or the studies of Feddersen-
Petersen (1990) on breed-specic environmental needs and
ontogenetic changes]. However, even today, studies on
between-breed similarities and differences often lack the nec-
essary systematic approach based on ecological validity in
behavioural sciences. Apart from some recent endeavours
that applied evolutionary theory (e.g. based on dog clades
genetic distances from a hypothetical ancestor; e.g. Parker,
2012), to establish a molecular genetic background for
breed-related behavioural features (e.g. Morrill et al., 2022),
dog breeds mostly appear in behavioural studies as either a
targeted independent factor (Serpell & Duffy, 2014), or in
ad-hoc comparisons based on the most popular breeds
(e.g. Pongracz et al., 2005; Junttila et al., 2022). While rese-
archers often aim to answer questions related to the assumed
different selection past of various dog breeds (e.g. Udell
et al., 2014), they rarely include more than a few hand-
pickedbreeds in their investigation, with the results inevita-
bly impacted by numerous additional differences among the
chosen breeds (e.g. Pogany et al., 2018; Ujfalussy et al., 2023).
In this review, we focus on studies from the last few
decades where behavioural researchers tested multiple dog
breeds and presented breed-related results. We provide a
brief enumeration of the typical aims of these papers, as well
as their focal breeds (or breed groups). Then, through exam-
ples, we critically analyse whether their methodologies were
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
Behaviour of dog breeds 69
suitable for achieving their declared goals. Finally, based on
the principles of the SWOT (Strengths, Weaknesses,
Opportunities and Threats) method (e.g. Van Belle
et al., 2024), we synthetise recommended future research
strategies that reect the fundamental criterion of ecological
validity (biological relevance) for investigations of breed-
related behavioural similarities/differences of dogs.
II. METHODS: LITERATURE SURVEY
We performed a literature search on two separate occasions:
October 16, 2023, using Google Scholar; and June 3, 2024
using Science Direct, to identify relevant literature that involved
comparative behavioural analysis of dog breeds. On both
occasions, we ran the same three consecutive searches using
the search terms: dog breeds AND behaviour,dog breeds
AND learning,anddog breeds AND communication.For
each search, the rst 100 results were processed, thus a total of
600 publications were analysed in detail (i.e. reading the titles
and abstracts), to select suitable articles for our review.
Our primary focus was on original research papers and
book chapters. Review articles, monographs, conference
abstracts, and dissertations were not included. We excluded
duplicate hits and publications based on topical mismatch
(see Table 1). Most of the excluded papers either reported
purely molecular genetic results with no highlighted beha-
vioural relevance, did not include behavioural, or
behaviour-related analysis, lacked any breed-related
comparison, or did not include more than one dog breed.
Our nal list included 97 publications with data/results on
behavioural phenotypes of dogs that reported breed-related
comparisons.
III. RESULTS OF THE LITERATURE ANALYSIS
We assessed the 97 identied publications according to three,
hierarchically arranged characteristics:
(1) The typical reasons why authors compared the behaviour of dog
breeds (proximal goal), and conclusions (ultimate goal) of the study.
We separated these according to two main categories: (i) the
authors targeted fundamental research questions while com-
paring particular breeds or breed groups; or (ii) the goals/
conclusions were chosen according to an applied question
with regard to breed or breed group comparisons
(e.g. training, safety, companion animal related).
(2) Breed choice.Weseparatedtheseaccordingtothreemain
methods: (i) hypothesis-driven/functional breed choice; where
authors analysed the results of either a few, or a larger number
of dog breeds (or breed groups), based on apriorifunctional
hypothesis. These hypotheses were linked with articial selec-
tion for particular working tasks, or anatomical features, or
physiological attributes of the dog breeds (breed groups);
(ii) hypothesis-driven/ancestry-based breed choice (e.g. wolf-like
versus more modern breeds, etc.). Here the authors investigated
the associations of behavioural traits with the genetic distance
between breeds or breed groups; (iii) convenience breed choice,
where the authors chose their breeds based on their availability,
oftenoptingforthemostcommonbreedsinaparticularloca-
tion/country. These studies commonly used the clustering sys-
tems of the large kennel clubs (FCI or AKC breed groups).
(3) The number of compared breeds. We sorted papers into two
clusters: (i) papers that compared no more than four breeds
were considered as using few breeds;and(ii)publica-
tions that used breed groups or numerous dog breeds for
comparisons were considered as using several breeds.
We opted for four breeds as cut-off between fewand
severalbreeds, because if authors intended to compare
breed groupsin a study, they used at least two groups
with a minimum of two breeds in each.
The results of this process are shown in Table 2.
IV. CRITICAL EVALUATION OF STUDY DESIGN
IN DOG BREED-RELATED BEHAVIOURAL
RESEARCH
(1) Convenience sampling of breeds caveats and
advantages
Most articles that we included had a proximal goal
focusing on breed-related (behavioural) differences.
Table 1. The type and number of papers identied by the liter-
ature search that were excluded from this review because the
topic of the paper did not meet our selection criteria (article
should provide behavioural or behaviour-related results that
involve dog breed comparisons).
Reasons for exclusion and example of
excluded study
Number
of papers
Veterinary breed identication (Simpson
et al., 2012)1
Paper focused on human behaviour (Wells &
Hepper, 2012)1
Anatomy-related paper (e.g. Vedat et al., 2023)2
Not dog-related paper (e.g. Lloyd et al., 2008)6
Paper analysed the subjective opinion of
respondents (e.g. Packer et al., 2017)8
Review paper (e.g. Mehrkam & Wynne, 2014)14
Paper focused on human societal issues (e.g.
Clarke et al., 2013)18
Veterinary report on health/disease issues (e.g.
Berg et al., 2024)19
Purely molecular genetic results, with no direct
behavioural links (e.g. Bionda et al., 2023)37
No behavioural data presented (non-genetic
papers) (e.g. ONeill et al., 2023)83
No breed comparisons (e.g. McGreevy &
Nicholas, 1999)148
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
70 Péter Pongracz and Petra Dobos
Table 2. Results of the literature survey. Publications (N=97) included in this table both (i) reported the results of behavioural tests, behaviour-related analyses, or surveys on
dog behaviour, and (ii) compared more than one dog breed, or groups of breeds.
Research aim/scope of
conclusions
Method of breed (breed
group) choice
Number of breeds
(breed groups) References
Association between behaviour
and various breeds (breed
groups)
Hypothesis-driven, functional Several breed groups, several
breeds in each Bognar et al.(
2021); Dobos & Pongracz (2023); Gacsi et al.(2009);
Hecht et al.(
2019); Hecht et al.(2021); Helton & Helton (2010);
Lenkei et al.(
2021a); Clarke et al.(2019); Svartberg (2006)
Few (24) breeds Kovacs et al.(
2016); Eretovaet al.(2024); McGreevy et al.(2010);
Ujfalussy et al.(
2023)
Hypothesis-driven, ancestry-
based Several breed groups, several
breeds in each Hansen Wheat et al.(
2019); Kerswell et al.(2009); Konno et al.
(2016); MacLean et al.(2019); Morrill et al.(2022); Smith et al.
(2017); Tonoike et al.(2015); Vaysse et al.(2011); Dutrow et al.
(2022)
Few (24) breeds Nagasawa et al.(
2017); Nagasawa et al.(2024)
Convenience (popular
breeds) Several breeds Dorey et al.(
2009); Feddersen-Petersen (2000); Gnanadesikan
et al.(
2020); Hart & Hart (1985); Hart & Miller (1985);
Horschler et al.(
2019); Lit et al.(2010); Pongracz et al.(2001);
Pongracz et al.(
2005); Serpell & Duffy (2014); Riedel et al.
(2008); Turcsan et al.(2011); Salonen et al.(2023); Eo et al.
(2016)
Few (24) breeds van den Berg et al.(
2010); Niimi et al.(1999); Maglieri et al.(2019);
Persson et al.(
2018); Jakovcevic et al.(2010); Burza et al.(2022)
Applied aspects of breed
behaviour associations Hypothesis-driven, functional Several breeds Caddiell et al.(
2023); Christiansen et al.(2001); Hammond et al.
(2022);
Helton (2009); Polgar et al.(2016); Pongracz et al.(2020); Van
Poucke et al.(
2022)
Few (24) breeds Fadel et al.(
2016); Kinka & Young (2018); Strychalski et al.
(2015); Overall et al.(2016); Sundman et al.(2016);
Vas et al.(
2005)
Hypothesis-driven, ancestry-
based Several breeds Marshall-Pescini et al.(
2016); Wobber et al.(2009); Wojcik &
Powierża(
2021)
Few (24) breeds
Convenience (popular
breeds) Several breeds Anderson et al.(
2022); Asp et al.(2015); Bellamy et al.(2018);
Chapagain et al.(
2017); Col et al.(2016); Cornelissen &
Hopster (2010); Creedon & Ó Súilleabhain (2017); Donohue
et al.(
2024); Ekiz et al.(2023); Essig et al.(2019); Ghirlanda et al.
(2013); Helton (2010); Kogan et al.(2019); McGreevy et al.
(2013); Notari & Goodwin (2007); Salvin et al.(2012);
Schalamon et al.(
2006); Starling et al.(2013); Storengen &
Lingaas (2015); Sundman et al.(2020); Vajanyi et al.(2024);
Westgarth et al.(
2010); Zapata et al.(2022)
Few breeds (24) Andelt (1999); Baranyiovaet al.(2007); Bloom et al.(2021); Ott
et al.(
2008); Ott et al.(2009); Sandøe et al.(2017); Wright et al.
(2007); Rice & Velasco (2023); Wilsson & Sundgren (1997);
Morrow et al.(
2015); Jezierski et al.(2014); Santariovaet al.
(2023); Bowden et al.(2018)
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
Behaviour of dog breeds 71
However, methodologies differed greatly. Many papers
used dog breeds as a grouping (independent) variable
without an apriorihypothesis, resulting in an exploratory
study instead of stating why the authors expected particu-
lar dog breeds would behave differently from others
(e.g. Hart & Hart, 1985;Turcsan, Kubinyi & Miklosi,
2011;Ghirlandaet al., 2013). In other cases, authors
targeted various behavioural (e.g. Hecht et al., 2021),
socio-cognitive (e.g. Gnanadesikan et al., 2020), or
temperament-based (e.g. Zapata et al., 2022) phenotypes,
and assumed that dog breeds (or sometimes breed groups;
e.g. Pongracz et al., 2005) would show consistent variability
along these scales. The way dog breeds were included in
these investigations was most commonly based on conve-
nience sampling, which in practice mirrored the most
abundantly encountered (popular) breeds through large-
scale behavioural assessment (Pongracz et al., 2005), ques-
tionnaire (Turcsan et al., 2011;McGreevyet al., 2013), and
veterinary databases (Anderson et al., 2022). The potential
strength of this approach is access to very high numbers
of individual records (up to 10,000; e.g. Serpell &
Duffy, 2014), usually from a wide array of dog breeds.
The results therefore can be regarded as representative,
at least for breeds that contributed large numbers to the
sample. However, these surveys face an inherent pro-
blem of being explorative [e.g. the pioneering study of
Feddersen-Petersen (2000) on between-breed differences
in vocalisations], which limits the possibility of drawing
ultimate conclusions regarding, for example, selection
processes resulting in breed (or breed-group)-related
behavioural differences. For example, Pongracz et al.
(2005) investigated breed-related associations in how ef-
ciently dogs could master a detour task on their own, as
well as after observing a human demonstrator making
the detour. The method of breed choice limited their anal-
ysis to the 10 most common dog breeds at dog schools,
which inevitably led to skewed selection. The sample con-
sisted of mostly cooperative breeds [sheepdogs, gundogs
and utility (police) dog breeds], with only two breeds that
were selected for independent working tasks (a livestock
guardian and a terrier breed). The authors did not nd dif-
ferences in breed performance in either the trial-and-error
or social learning scenario. However, their unstructured
convenience sampling of breeds would make it difcult to
identify major effects regarding capacities of dogs that
seem quite generally present in the included species
[e.g. the capacity to pay attention to humans (Topal,
Kis & Olah, 2014) and performance in detour-like spatial
tasks (Pongracz et al., 2001)].
The limitations of convenience breed choice are not
always obvious at rst sight: many of the surveyed articles
contained conclusions that referred to assumed evolutionary
changes since domestication (e.g. Konno et al., 2016; Hansen
Wheat et al., 2019), or post-domestication selection
[e.g. working function (Pongracz et al., 2005); doghuman
interactions (Kogan et al., 2019)]. However, in the absence
of carefully planned breed sampling, the resulting random
(i.e. popularity/availability based) inclusion/exclusion of
breed representatives will result in numerous alternative
explanations for the results. Thus, availability-based breed
comparisons are best restricted to explorative detection of
consistent behavioural differences (e.g. Serpell & Duffy,
2014; Hansen Wheat et al., 2019). For investigating causative
relationships (e.g. the effect of selection on dog behaviour in
general, or on particular behavioural phenotypes), a
planned, systematic choice of breeds (or breed groups) is
recommended.
(2) Planned breed choice
Within the framework of our survey, we encountered two
main types of planned breed choice. Their common feature
was that the authors usually targeted groups of breeds
(or breed groups, breed types) as a planned independent fac-
tor, however, they included either (i) only one breed (or very
few breeds) per group as a representative(e.g. Vas et al.,
2005), or (ii) multiple breeds from each group
(e.g. Dobos & Pongracz, 2023). Using only one, or very few
breeds per group unavoidably limits the scope of conclusions
that can be drawn from the results. No matter how well the
given dog breed represents a group, there will be additional
phenotypes that confound the results. For example, in the
study of Ujfalussy et al.(
2023), the authors found that brachy-
cephalic English and French Bulldogs showed more pro-
nounced gazing behaviour towards nearby humans than
the mesocephalic Mudi dogs in the so-called unsolvable
task. The authors argued that this result showed that breed-
ing dogs for extremely short heads could result in paedomor-
phic (i.e. strongly dependent) behavioural characteristics
compared to normocephalic dog breeds. However, with this
very limited choice of breeds the study could not convinc-
ingly reject alternative hypotheses, such as the potential
effects of functions of these breeds: Mudis are herding dogs,
while French and English Bulldogs have long acted as com-
panion animals. Another study, also using the unsolvable
task, compared only three breeds (Czechoslovakian
Wolfdogs, German Shepherd Dogs and Labrador
Retrievers), to see whether an assumed wolf-likenessor
dog-likenesswas associated with willingness to look at
humans during the task (Maglieri et al., 2019). Unfortunately,
as the Czechoslovakian Wolfdog was originally created by
hybridising wolves with German Shepherd Dogs to produce
a high-endurance border patrol breed (Moravˇ
cikova
et al., 2021), any comparison with one of its originators (the
German Shepherd Dog) and Labrador Retrievers, a gundog
breed, cannot provide meaningful information about
whether differences can be attributed to distance from wolf-
like ancestors of all dog breeds. Finally, Kovacs et al.(
2016)
treated two dog breeds (Siberian Huskies and Border Collies)
with intranasally administered oxytocin, to investigate
whether their reactions were different in tasks where they
had to interact with people. The authors found that the social
responsivenessof Border Collies was correlated with a stron-
ger effect of oxytocin, and argued that selection for
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
72 Péter Pongracz and Petra Dobos
cooperativeness in this herding dog breed could explain this
effect, compared to the independently working sled dog
Huskies. However, as only one representative breed from each
breed group (cooperative versus independent working dogs)
was chosen, it is not possible to exclude confounding effects
such as a different evolutionary past (Huskies belong to the
ancientbreeds, while Border Collies are a more derived
or youngerdog breed; Parker et al., 2017).
To avoid the limitations inherent in representing entire
breed groups with a single or very limited number of breeds,
an alternative is to test/survey as many breeds as possible
within each cluster (e.g. Starling et al., 2013). If the experi-
mental design can ensure that none of the breeds become
over-represented within their clusters (Dobos & Pongracz,
2023), this method offers an advantage: with many included
breeds it is less likely that non-targeted confounding factors
will bias the results. However, the choice of grouping variable
is still crucial. Here we stress the importance of biological rel-
evance and ecological validity in ethological research. In
some papers, breed groups were dened according to criteria
from a purebred dog-breeding organisation such as the AKC
or FCI (e.g. Turcsan et al., 2011). Although such systems go
some way towards dening groups based on the origin and
function of the breeds, non-scientic traditions of purebred
dog breeding, and more recent breed introductions, have
created a rather confusing structure across these categorisa-
tions. Although the FCI breed groups (Table 3) seem to have
a functional structure, and these groups show considerable
overlap with the genetic clusters established by Parker &
Ostrander (2005), some of their groups are comprised of a
bewildering array of breeds (e.g. Group 1, which contains
almost all the herding and livestock-guarding breeds), while
others focus on a handful of very closely related breeds
(e.g. Group 4, Dachshunds). The AKC breed groups
(Table 4), which seem to be used most often in the surveyed
literature, offer almost no biological relevance/ecological
validity for a behavioural researcher. The AKC breed
groups represent an odd mixture of straightforward
functionality/origin (e.g. terriers, herding dogs); however,
some of their breed groups are comprised of a difcult-
to-categorise array of breeds. The AKC itself even admits
their lack of clarity (https://www.akc.org/expert-advice/
lifestyle/7-akc-dog-breed-groups-explained/): The breeds
of the Non-Sporting Group have two things in common: wet
noses and four legs. It is therefore not surprising that it is dif-
cult to attribute a cause to behavioural differences between
breeds in the AKCs groups, apart from some trivial differences
(e.g. terriers are bolderthan herding dogs while herding dogs
are more trainablethan hounds; Turcsan et al., 2011). Indeed,
it is hard to predict results for such complex groupings as
Non-Sporting,orSportingdogs. In such studies, the
group-level results could easily be biased by a few similarly
behaving and well-represented breeds in an otherwise het-
erogeneous group. By contrast, the heterogeneous nature of
clusters dened by dog breeding organisations could mask
likely existing behavioural differences. Dorey, Udell &
Wynne (2009) found no association between point-following
capacity and AKC breed group. Relying on the visual (point-
ing) signals of humans is a widespread and well-documented
capacity of dogs (Pongracz et al., 2013), and one might expect
that the function of a dog breed could affect this behaviour.
However, the breed groups of the breeding organisations
often lump very different breeds together, which could blur
potential differences. To summarise, it is likely that breed
clusters from the large dog breeding organisations do not
provide a biologically relevant grouping variable for etholog-
ical investigations.
(3) Is there any way to create ecologically valid
multi-breed comparisons?
The fact that hundreds of dog breeds are currently recog-
nised is undoubtedly the result of human attempts to stan-
dardise and preserve distinct landraces of working dogs,
mostly in the second half of the 19th century (Serpell &
Duffy, 2014). Landraces originated as behaviourally useful
Table 3. The 10 breed groups of the Fédération Cynologique Internationale (FCI), which is the worlds largest kennel club organi-
sation based on the number of member countries. Most FCI groups are dened according to the dog breedsoriginal function, but
some, for example Group 5, can also be considered as ancestry-based cluster. For each group, we provide a conventionalexample
that most people could easily assign to that group, and when possible, an unconventionalbreed that might be more surprising.
FCI group Conventional breed example Unconventional breed example
Group 1: Sheepdogs and Cattledogs (except Swiss
Cattledogs) Australian Shepherd Czechoslovakian Wolfdog
Group 2: Pinscher and Schnauzer Molossoid and Swiss
Mountain and Cattledogs Dobermann Russian Black Terrier
Group 3: Terriers Airedale Terrier American Staffordshire Terrier
Group 4: Dachshunds Dachshund
Group 5: Spitz and primitive types Alaskan Malamute Icelandic Sheepdog
Group 6: Scent hounds and related breeds English Foxhound Dalmatian
Group 7: Pointing dogs Vizsla Brittany Spaniel
Group 8: Retrievers Flushing Dogs Water Dogs Labrador Retriever
Group 9: Companion and Toy Dogs Bolognese Standard Poodle
Group 10: Sighthounds Greyhound Irish Wolfhound
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
Behaviour of dog breeds 73
working companions, aiding their owners in a multitude of
tasks (Lord, Coppinger & Coppinger, 2014). Capitalising
on the realisation that articial selection could potentially
result in fundamentally different socio-cognitive capacities
among working dogs, depending on their intended deploy-
ment, some researchers have investigated behavioural dif-
ferences between the main clusters of working dogs.
Comparison between independentand cooperative
working dogs (Gacsi et al., 2009) has been an especially
promising and widely applicable paradigm. Many indepen-
dent breeds have been selected for tasks in which they have
to operate either out of sight of their handlers, or without
being regularly instructed. Cooperative breeds on the other
hand, have been selected for tasks where they perform
under close human supervision with regular instructions.
The specic advantage of using this grouping is that both
the independentand the cooperativegroups are com-
prised of a wide variety of breeds, originating from often
very distant genetic clades (Parker et al., 2017; Dobos &
Pongracz, 2023). Thus, when the test groups are assembled
from evenly represented and widely distributed breeds, any
signicant behavioural differences between the two groups
are less likely to be confounded by within-group genetic
relationships among the breeds. Obviously, to ensure a reli-
able breed-group effect, other factors such as the dogs
training level (Serpell & Duffy, 2014) and housing condi-
tions (Lenkei, Pogany & Fugazza, 2019)shouldalsobebal-
anced across the groups. From a more theoretical point of
view, an ownerschoice of a particular breed is likely to be
biased by their preference for not only a particular appear-
ance, but also for the assumed behavioural and personality
traits of that breed. In turn, owners will likely engage their
dogs with joint activities that t expectations for that partic-
ular breed. For example, cooperative breeds such as herd-
ing dogs and utility breeds (e.g. German Shepherd Dogs,
Belgian Malinois) are preferentially used for activities that
require high levels of attention for commands and signals
(e.g. agility, obedience); independently working dog breeds
are likely trained for activities where determination and
stamina are needed (e.g. sled dogs in canicross and bikejör-
ing; Staffordshire and Pitbull terriers in weight pulling).
Breed-appropriatetraining and activities may further
strengthen particular behavioural phenotypes in the dogs
as well as breed-related stereotypes among people
(e.g. Clarke, Cooper & Mills, 2013).
Although the independentversus cooperativeworking
breeds comparison offers an ecologically valid approach to
the comparative analysis of behaviours that are connected
to doghuman interactions, it is crucial that there is represen-
tative sampling of the dog breeds for a given study. If
researchers only test a handful of breeds, the problems dis-
cussed above again arise where an over-represented breed
could bias the results. For example, Kovacs et al.(
2016) drew
conclusions about differences in human-directed gazing for
Siberian Huskies and Border Collies based on the alleged
effects of selection for cooperativity or independent work.
However, using only a single breed per cluster cannot pro-
vide a generalisable effect for the whole group of breeds, as
the randomly chosen two breeds differ in many other features
(e.g. genetic distance from the common ancestor; typical
housing conditions, training level), and not only in their
work-related ancestry. Similarly, the study of Pogany et al.
(2018) employed only four dog breeds, three cooperative
(Labrador Retrievers, Border Collies and Mudis) and an
independent-working breed (Beagles). The authors found
differences between the breedsreward-maximising behav-
iour in a cognitive bias task, and concluded that this may
be the consequence of the working style of the breeds. How-
ever, again, the unevenly distributed and very low number of
breeds would preclude such ambitious explanations.
Nevertheless, some studies used high numbers of breeds
for both functional clusters, allowing well-supported conclu-
sions about the typical behavioural proles of independent
and cooperative breeds. Gacsi et al.(
2009) showed that coop-
erative breeds follow human pointing signals with higher suc-
cess rates than independent working breeds. Lenkei
et al.(
2021a) found that the capacity to form an attachment
bond with the owner is invariably present in both breed clus-
ters, supporting the idea that dogowner attachment is a fun-
damental, species-level attribute of dogs. Bognar et al.(
2021)
tested the time taken to establish eye contact with humans in
breeds varying in work function, cephalic index and age. The
authors found that cooperative dogs and mongrels established
eye contact with humans more rapidly than did independent
working dogs. Shorter headed dogs also established eye con-
tact faster. This well-designed study posed biologically valid
questions, however it was somewhat limited by the relatively
low number of breeds and purebred subjects, especially from
the independent breeds. Recently, Dobos & Pongracz (2023)
showed that although both independent and cooperative
breeds show similar performance in the V-shape fence detour
task, they behave differently when the task is demonstrated by
a human experimenter. While cooperative dogs learned how
to detour more efciently, the independent dogs did not utilise
the opportunity for observational learning. All four of these
Table 4. The seven breed groups of the American Kennel Club
(AKC), which is the most signicant dog breeding organisation
in the USA. The AKC groups were primarily formed on the
basis of breed purpose/function. For each group, we provide a
conventionalexample that most people could easily assign to
that group, and when possible, an unconventionalbreed that
might be more surprising.
AKC group Conventional
breed example
Unconventional
breed example
Sporting Golden Retriever
Hound Beagle Basenji
Working Rottweiler Akita
Terrier Border Terrier Miniature Schnauzer
Toy Pug Italian Greyhound
Non-sporting Bulldog Standard Poodle
Herding Border Collie Spanish Water Dog
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
74 Péter Pongracz and Petra Dobos
studies employed dozens of breeds from both clusters and the
researchers took care not to over-represent any of the included
breeds. As a result, their ndings can be considered as biolog-
ically relevant features of the investigated breed groups, result-
ing from selection for working companions with various levels
of cooperativity.
(4) Can ancestry provide a biologically relevant
basis for breed-related behavioural comparisons?
In our survey we found several papers that based between-
breed comparisons on ancestry-related features. While this
method may suffer from the aforementioned problems if it
is applied to a handful of breeds only (e.g. Udell et al., 2014;
Nagasawa et al., 2024), where genetic relationship-based
behavioural analysis is carried out on a large number of
breeds (e.g. Morrill et al., 2022), or if sufciently sampled
breed clusters are compared (e.g. Hansen Wheat et al.,
2019), it can be a promising method for biologically relevant
investigations.
Some large-scale molecular-genetic surveys targeted beha-
vioural phenotypes and provided useful information about
the genetic background of such behaviours, or socio-
cognitive capacities with high ecological relevance in com-
parisons of dog breeds. For example, based on the genetic
analysis of more than 2000 dogs (with roughly half being
purebreds), Morrill et al.(
2022) found that behaviours show-
ing the strongest between-breed segregation belonged to
clusters that characterise either the cooperative or the inde-
pendent working dog types. The cooperative breeds scored
highly on such genetically determined features as biddabil-
ityand easy to train. Remarkably, in this study, single
individual breeds could not be characterised with breed-
typicalbehaviours, suggesting that functional clusters of
breeds could be key to understanding more recent tendencies
in behavioural selection among dog breeds. Additionally, the
increasingly prevalent segregation of behaviourally different
workingand showlines in many dog breeds may be
responsible for maskingpreviously established breed-
typical behaviour (Sundman et al., 2016). Vaysee et al.
(2011) performed genome-wide mapping with a genotyping
array of more than 170,000 single nucleotide polymorphisms
(SNPs), looking for regions that show between-breed differ-
ences in their associations with morphological and beha-
vioural traits. Their sample consisted of more than
500 dogs from 46 breeds. The behavioural trait boldness
(where the binary classication of boldversus non-bold
breeds was taken from Jones et al., 2008) showed a signicant
association with the breedsbody size and ear position: small
breeds with pricked ears tended to belong to the boldcat-
egory, while all but one of the sampled drop-ear breeds were
classied as non-bold. Obviously, these results cannot
establish reliable causative connections between the breeds
behavioural phenotype and their selection past, for which
researchers would need to control for the genetic relatedness
of the breeds and also, for example, their traits of functional
selection. Regarding morphological traits such as ear
position, direct surgical alterations further complicate
interpretation of the results of Vaysee et al.(
2011), as the
Boxer and the Dobermann breeds were classied as bold,
but these dogs only become prick earedif their ears are
cropped, as both breeds naturally have drop-ears.
In some instances, the experimental design may prevent
extrapolation of conclusions. Konno et al.(
2016) compared
representatives of various dog breeds in visual contact-
seeking tasks with humans and concluded that ancient
breedsperform with lower intensity in these tasks than dogs
they sorted into various other groups (herding,working,
retriever-mastiffand hunting). The authors explained
their results in an evolutionary/ancestry-based framework,
arguing that looking at humans is weakly represented in
wolves (Miklosi et al., 2003), thus it would likely also be weak
in ancientdog breeds. However, their group of ancient
breeds also differed from most of their other groups on the
basis of cooperativity another factor associated with dog
human visual interactions (Gacsi et al., 2009). In another
study, Nagasawa et al.(
2017) tested Japanese dog breeds
belonging to the ancientcluster of breeds for gazing and
contact-seeking behaviour towards their owner after intrana-
sal treatment with oxytocin. They hypothesised that breeds
closer to their wolf-like ancestors would show weaker
human-directed gazing. Although the authors did record
human-directed gazing after oxytocin treatment in the
ancient Japanese breeds, as their study lacked any subjects
from Westernbreeds as a comparison, it is difcult to draw
rm conclusions. Ancestry-based genetic clustering may not
necessarily result in an explanation for variance in beha-
vioural traits that involve complex social understanding and
interactivity with humans. Dorey et al.(
2009) performed a
meta-analysis of previous publications, and found that the
success rate of dogspoint-following behaviour was not asso-
ciated with the four ancestry-based clusters dened by
Parker & Ostrander (2005). Recall that point-following
capacity was associated with purebred dogsassignment to
either the independent or the cooperative breed clusters
(Gacsi et al., 2009). This perhaps explains why the genetic
clusters did not provide similar results, because even closely
related breeds have been selected for very different working
tasks. For example, many sighthounds and herding dogs are
closely related (Parker et al., 2017), but the former breeds
were selected for ability to work independently, whereas the
latter work cooperatively with their handler. The potential
role of functional (work-related) selection can be inferred from
the investigation of Gnanadesikan et al.(
2020), who estimated
the heritability of cognitive features across breeds. They
used the citizen science behavioural database Dognition.
com, from which they extracted records of more than 1,500
purebred dogs from 36 commonly occurring breeds. Using
genetic relatedness data from Parker et al.(2017), they found
the highest heritability indices for the behavioural traits
inhibitory controland communication. Gnanadesikan
et al.(2020) speculated that the strong heritability of these traits
might be the result of their crucial role involvement in domes-
tication. It is our opinion that an alternative hypothesis could
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
Behaviour of dog breeds 75
be that thesetraits have been strongly affected by more recent
directional selection for particular working tasks. Posing an
ecologically valid research question is of crucial importance
when researchers apply ancestry-based (genetic) methods for
behavioural breed comparisons.
A clear and biologically relevant hypothesis was presented
by Smith, Browne & Serpell (2017), who compared the prob-
lematic behaviours of dingoes kept as companions with mod-
ern and ancient dog breeds. They used thousands of records
from the validated Canine Behavioural Assessment and
Research Questionnaire(C-BARQ) instrument and found
that dingoes (primitive dogs) represented an outlier, even
when compared to the ancient breeds. Dingoes were less
trainable, showed more human-directed fear, and a higher
propensity to roam and escape, than ancient and modern
dogs. The authors concluded that the behaviour of dingoes
may reect a very early domestication effect, followed by nat-
ural, rather than articial selection. Dingoes are only recently
and still rarely kept as companion dogs, with environmental
factors such as socialisation, housing and training conditions
also potentially relevant to their observed behavioural traits.
In a similarly well-designed study, Hansen Wheat et al.(
2019)
used an immense database of the Swedish Kennel Club con-
taining results from almost 80,000 purebred dogs tested
using the Dog Mentality Assessment(DMA) procedure.
The DMA consists of a series of behaviour tests and has a val-
idated prole of the evaluated behavioural traits
(Svartberg, 2005). Hansen Wheat et al.(2019) hypothesised
that there would be a difference between the ancientand
moderndog breedsbehavioural traits typical for the
domestication syndrome. According to this syndrome
(Kaiser, Hennessy & Sachser, 2015), domesticated animals
show a general increase in sociability, and a decreased reac-
tivity prole (e.g. lower aggression and fear levels). In a com-
parison of the DMA results from seven ancient and
71 modern dog breeds, Hansen Wheat et al.(
2019) found that
ancient dog breeds show a consistent relationship between
sociability and reactivity as expected according to the domes-
tication syndrome. However, the two main traits were
decoupled across the modern breeds (Hansen Wheat
et al., 2019). As ancient breeds are thought to be relatively
unchanged across longer time periods, together with a con-
siderable admixture with wolves (VonHoldt et al., 2010),
these results t with the hypothesis that the earliest
(ancient) dog population showed more uniform effects of
domestication. Modern breeds are the products of more
recent functional and morphological selection (Parker
et al., 2017). Consequently, this study convincingly drew
attention to the more specic needs of humans for specialised
working companions, whereby sociability and reactivity were
sometimes given different importance in modern breeds.
(5) Dog breed comparisons in light of applied
ethology
A large proportion of publications in this survey focused on
behavioural traits with applied relevance, that is they are
important from the aspects of choosing, training or
co-existing with dogs as working or companion animals.
Breed comparisons have great relevance from this point
of view. Although the applied investigations are often con-
structed around a well-denedresearchquestionand
hypothesis, we still found issues regarding study design/
breed choice. Below we summarise the main tendencies
and typical approaches used.
(a)Problematic behaviours
When surveying and comparing the behavioural characteris-
tics of dog breeds, researchers often try to nd a solution to
behavioural problems. This includes helping owners choose
proper breeds for their needs (e.g. Notari & Goodwin,
2007), or surveying populations for the potential cause of
problematic behaviours (e.g. dangerous dog breeds;
Hammond et al., 2022). This is obviously a complex situation,
as membership of a particular breed cannot be a fully reliable
predictor of (problematic) behaviours. Environmental factors
[e.g. early-life environment (Lenkei et al., 2019); socialisation
(Martínez et al., 2011); traumatic events (Wallis, Szabo&
Kubinyi, 2020); training (Burghardt, 2003)]; as well as
within-breed articial selection for distinct lines of working
and show linetypes (Fadel et al., 2016) can generate consid-
erable within-breed behavioural variability. Behavioural
issues often inuence the relinquishment of dogs to shelters
(Patronek, Bradley & Arps, 2022) and their chances of adop-
tion also depend on the potential adopting ownersknowl-
edge about their behaviour. Wright et al.(
2007) found that
exposure to a video clip of an aggressive (misbehaving) dog,
enhances the formation of negative breed stereotypes for
the breed in the video (and similar dogs). The limitation of
this study design was that they used only four dog breeds
(German Shepherd Dog, Bloodhound, Border Collie,
Pointer), and only the German Shepherd Dog was used for
the video clip.
Random (convenience) breed sampling can lead to prob-
lems with interpretation of results in some studies. Bellamy
et al.(
2018) investigated the genetics of fearful behaviour in
Bichon Havanese dogs (a breed with considerable variation
in fearful/outgoing behaviours). They found that associa-
tions of two SNPs at the DRD2 gene increased social fear
in the Havanese. When they tried to link associations of these
SNPs with noise reactivity in an additional four breeds
(Standard Poodle, Nova Scotia Duck Tolling Retriever, Irish
Soft Coated Wheaten Terrier, Collie), they found contradic-
tory results (positive versus negative associations in two versus
three breeds). The low generalisability of their results could
be connected to a seemingly random choice of breeds.
Large sample sizes often provide a more representative
picture; however, convenience sampling remains problem-
atic from the aspect of uncontrolled confounding factors. In
a questionnaire study, Storengen & Lingaas (2015) analysed
the responses of more than 5000 owners regarding the
noise-sensitivity of their dogs. Breed choice was arbitrary,
and was based on the willingness of 17 breed clubsto
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
76 Péter Pongracz and Petra Dobos
participate. Although the authors reported a signicant
breed effect of noise sensitivity, the dogsage, sex and repro-
ductive status, as well as sensitivity to separation, acted as
confounding factors. Thus, the identied breed differences
could not be explained on the basis of ancestry or breed
function.
As problematic behaviours usually have a complex aetiol-
ogy and causative background (e.g. separation-related prob-
lems; Lenkei et al., 2021b), it is potentially hard to identify
biologically relevant associations between them and individ-
ual dog breeds. McGreevy et al.(
2013) used the C-BARQ
instrument (with more than 8000 responses concerning the
49 most popular breeds in Australia) to compare behavioural
problems with breed body mass, height and cephalic index.
They found that unlike trainability, problematic behaviours
increased with decreasing body size. Also, shorter headed
dogs exhibited more allogrooming and a lower propensity
to chase. However, as both dog size and cephalic index can
be associated with multiple other factors (e.g. breed function,
housing conditions, longevity; Turcsan & Kubinyi, 2024),
their ndings remain difcult to interpret without specic
follow-up studies. Regarding their results, the authors aptly
concluded in their paper The biological basis for, and signif-
icance of, these associations remain to be determined.
(McGreevy et al., 2013). However, hypothesis-driven appro-
aches can provide biologically relevant results even for
proneness to particular behavioural problems. Pongracz,
Gomez & Lenkei (2020) tested whether dogs from coopera-
tive or independent working breeds show more signs of stress
during a short separation period from their owner. Coopera-
tive working dogs reacted more quickly and with more fre-
quent distress vocalisations, which may be the consequence
of their more pronounced preference for remaining in the
vicinity of their owner.
(b)Working dogs
During the last century, even dog breeds that originally
existed only as utility (working) animals, have become com-
panions. However, there is still a need for working dogs in
various elds, and some traits can be important for maintain-
ing the efciency of these populations. In our survey we
encountered mostly well-designed evaluations of working
dogs and their relevant behavioural phenotypes. Kinka &
Young (2018) compared three Old World livestock guarding
breeds with American Whitedogs (mixed-breed livestock-
guarding dogs, developed in North America, from Eurasian
livestock guarding breed founders) in their working style
and efciency with sheep, and their responses to simulated
wolf attacks. The authors found that all breeds were suitable
for the task, with only small between-breed differences.
As the capacity to detect odour is an important factor for
scent-work, Polgar et al.(
2016) compared the olfactory per-
formance of three groups of dog breeds (scent hounds, other
working dogs, brachycephalic breeds) and socialised wolves
in a natural scent-detection task. With a wide selection of
breeds included, they found that scent hounds and wolves
outperformed the other breeds, showing the effects of natural
(in the case of the wolf) and articial selection (in the case of
the scent hounds) on olfactory performance. Another impor-
tant feature in working dogs is their trainability. Knowing the
association of trainability with various inherited factors could
provide important insights for selecting the best candidates
for costly training programs. Helton (2009) investigated the
relationship between dogshead shape and their perfor-
mance in various tasks requiring training. Trainability of
the breeds was categorised by using the Coren (1994) ranking
scale. The results showed that breeds with high trainability
were mostly mesocephalic, while both brachy- and dolicho-
cephalic breeds fell into the less trainablecategory. Helton
(2009) concluded that selecting for ghting (shorter heads) or
running fast during hunting (longer heads) are specialised
functions that may require less training. This study utilised
an interesting functional approach with a well-outlined bio-
logical relevance. Among its limitations are the questionable
validity of the scoring system and the using of cephalic index
as a categorical factor instead of as a continuous variable (see
Georgevsky et al., 2014).
(c)Interacting with dogs
Breed comparisons can provide insights into behavioural and
personality characteristics of importance to dog owners, vet-
erinarians, and even legislators (Kogan et al., 2019). For
example, distinct workingand show/companionlines
started to appear in several dog breeds during the last cen-
tury, and it may be important to understand whether they
exhibit consistently different behaviours. Fadel et al.(
2016)
used the results of the Dog Impulsivity Assessment Scale
(DIAS) test battery on over 1000 Border Collies and Labra-
dor Retrievers to investigate whether impulsivity scores dif-
fered between show and working lines in these breeds.
They found that Border Collies were more impulsive than
Labradors, but only for the working lines. We can conclude
that recent breeding efforts for show/companion types in
some typical working breeds may have relaxed breed-typical
behavioural stereotypes (like impulsivity characteristics).
Sundman et al.(
2016) also evaluated thousands of Golden
and Labrador Retrievers, nding different curiosity-score
distributions, between their recently diverged hunting
and showlines.
Companion dogs with extreme featuresare very popu-
lar, despite many health and behavioural issues that nega-
tively affect the welfare of both the dogs and their owners.
Sandøe et al.(
2017) used a large-scale questionnaire survey
(nearly 1000 respondents), in which they compared owners
opinions about four small, popular dog breeds in Denmark.
In this well-designed study they included two breeds with
extreme features (Chihuahua, French Bulldog), the Cavalier
King Charles Spaniel that suffers from many health issues,
and Cairn Terriers that are a generally healthy breed.
Intriguingly, they found that owners of problematic breeds
cared less about health problems and would choose the same
breed again. By contrast, owners of Cairn Terriers
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
Behaviour of dog breeds 77
considered health as being more important. The study high-
lights that a preference for popular breeds with serious health
conditions often reects active and conscious decisions,
rather than lack of knowledge from the owner.
It is often thought that particular features could help to
sort dog breeds into particular types, which would be advan-
tageous for prospective dog owners to choose their best-
tting companion. A frequently encountered personality/
behavioural dimension in ethology and behavioural ecology
is the shynessboldness continuum (e.g. Wilson et al., 1994).
Starling et al.(
2013) used the C-BARQ instrument to investi-
gate the boldness supertraitin dogs owned by over 1000
respondents in Australia. They used the breed group struc-
ture of the UKC (United Kennel Club, USA), which is simi-
lar in its functionality to the FCI system but has fewer groups
(more suitable when researchers have fewer subjects).
Principal Components Analysis established one main trait
that had positive loadings on items describing playfulness
with humans and other dogs, and negative loadings on items
about fear. By including more breeds than is typical in other
surveys (e.g. ancient dogs, sighthounds), the study added new
details to the characteristic dimensions of the breeds, for
example, playful interactions with other dogs. Between-
breed, and between-group differences were established
on the shybold continuum. This study exemplies the
usefulness of considering a wide selection of breeds, and
the advantages of functional groupings. At the same time,
supertraits, such as boldness, might contain multiple
items, making it hard to interpret their meaning in every-
day practice.
Breed-clustering is an often-used practice that allows
researchers to investigate questions with practical applica-
tions. While inherited characteristics are usually the focus,
environmental effects, such as the training history of dogs,
can represent a decisive confounding factor. Marshall-
Pescini, Frazzi & Valsecchi (2016) investigated the effect of
training and breed group on dogsproblem-solving capacity
in the V-shaped detour and a puzzle box condition. While
breed group (ancestry-based; VonHoldt et al., 2010) did not
affect performance in the detour test, trained dogs were more
successful than untrained ones. For the puzzle box task, train-
ing enhanced dogssuccess, and working dogsperformed
better than retrievers and herding dogs. Although this study
was based on a biologically relevant question and methodol-
ogy, the breed choice showed signs of convenience sampling,
as all four groups consisted of only 23 breeds, and almost all
breeds in each group represented the cooperativefunc-
tional cluster.
V. DISCUSSION AND SWOT ANALYSIS
We found a large number of research papers where authors
performed comparative analysis of behavioural phenotypes
between dog breeds. The range of targeted breeds numbered
from a handful to many dozens, and the targeted behaviours
were relevant from aspects of both applied and fundamental
research. We identied three main strategies of research
design regarding the chosen methods the researchers used
to select dog breeds. Two variants of hypothesis-driven
approaches (based on either the function of the dog breeds,
or their genetic relatedness) and convenience sampling
(based on the availability/popularity of the dog breeds) were
equally common. A closer look at the combination of the ini-
tial aims of the reviewed papers with the methods of breed
choice and the conclusions drawn from their results, allowed
us to identify both positive aspects and weaknesses of these
methods. Below, we present a detailed SWOT analysis, in
which we highlight the characteristics of best practice
alongside caveats connected to the three approaches for the
choice of dog breeds (Table 5).
From this detailed review of the sampled publications, and
within the framework of SWOT analysis, it is clear that com-
parative research on the behaviour of dog breeds includes
multiple purposes and distinct research designs. However,
to nd biologically meaningful results, it is important to
identify the potentials and limitations of each method,
because this will fundamentally affect the scope and valid-
ity of any conclusions drawn. Therefore, during the selec-
tion of breeds for study, certain considerations should be
taken into account.
The most relevant threats to each of the reviewed research
designs were confounding factors that can hamper the appli-
cability and relevance of the results. These can be demo-
graphic and environmental features of the dogs, such as
their age, sex, housing conditions, and training levels. Unless
these potential confounding variables are the target of
research (e.g. age of the dog in Chapagin et al., 2017), their
effects should minimised, for example by balanced recruit-
ment of subjects. Serious issues can arise when the targeted
behavioural phenotype can be affected by mechanisms other
than those under consideration. Convenience sampling is
inherently sensitive to both ancestry- or breed function-based
effects, while ancestry- and function-based investigations can
mutually confound the others effect. These issues can be
avoided with a well-designed breed-choice plan where a suf-
cient number of breeds are included and there is no over-
representation of particular breeds. Additionally, a common
weakness noted in many of the reviewed methods was that
the choice of breeds did not serve the intended goals of the
research.
Convenience breed sampling choosing breeds randomly,
based on their availability is an explorative method, and
therefore suitable for research questions aiming to identify
the presence or absence of certain behaviours in the popula-
tion (e.g. prosocial and reactive behaviours; Hansen Wheat
et al., 2019). As this method is easy to apply, a wide variety
of breeds can be included, large sample sizes achieved
(e.g. Morrill et al., 2022), and the sample is likely to be repre-
sentative of the dog population in a particular location, or
time frame. However, the conclusions that can be reached
are limited, because even with a large number of breeds, var-
ious confounding variables can bias the results (e.g. original
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
78 Péter Pongracz and Petra Dobos
breed function, differences between individuals of the same
breed; Feddersen-Petersen, 2000). Many breed-related dif-
ferences would be better investigated using a hypothesis-
driven approach.
Hypothesis-driven sampling is the recommended method
to examine the effect of domestication and/or subsequent
articial selection on dogsbehaviour. Ancestry-based
molecular-genetic studies can provide ecologically valid
information about the genetic background of behavioural
phenotypes (Vaysse et al., 2011). For these questions, a com-
bination of convenience sampling with analysis of genetic
relatedness could allow for investigation of a large number
of breeds with some biological relevance (Serpell &
Duffy, 2014), but the use of hypothesis-driven sampling of
targeted breed clusters would be optimal to derive more pre-
cise and evolutionary valid conclusions (Smith et al., 2017).
An ancestry-based method is especially suitable for meta-
analyses of between-breed differences, and has gained popu-
larity in recent empirical research (e.g. dogs following human
pointing gestures; Dorey et al., 2009). However, when draw-
ing conclusions based on genetic relatedness, besides the
effects of domestication and early genetic-clade formation
based on certain behavioural traits, it is also important to
consider the potential effects of more recent articial selec-
tion (Gnanadesikan et al., 2020), as breeds with a similar incli-
nation for doghuman interactivity levels (e.g. cooperative
versus independent breeds) can be found in distant
genetic clades (Parker et al., 2017; Morrill et al., 2022;
Table 5. Overview of our ndings regarding the methods used to choose dog breeds in the surveyed publications. The three main
experimental designs were then evaluated according to the SWOT (Strengths, Weaknesses, Opportunities, Threats) principle
(Van Belle et al.,2024).
Experimental
design Assessment according to the SWOT principle
Hypothesis-driven,
functional breed
sampling
Strengths: based on biologically relevant hypotheses, which, in theory, should result in ndings of ecological
or practical (applied) validity.
Weaknesses: some dog breeds will inevitably be omitted if they cannot be sorted clearly into a functional
group.
Opportunities: a wide range of hypotheses can be tested, for both fundamental and applied themes. The
method is equally applicable for wider (breed-group based), or narrower (targeted to a few breeds only)
investigations although, in the latter, the question to be investigated should be specically tailored to the
involved breeds.
Threats: using only a few breeds, or allowing some breeds to be over-represented in breed-group
comparisons can lead to confounding breed-specic factors other than the targeted functional variable(s).
Unless the sample is assembled with careful balancing, confounding factors such as training level or housing
conditions can cause breed- or breed group-related bias.
Hypothesis-driven,
ancestry-based
breed sampling
Strengths: molecular-genetic studies provide a rm evolutionary (relatedness-based) background, which can
be effectively utilised as a predictor variable for a wide array of behavioural phenotypes.
Weaknesses: ancestry-based approaches are usually not readily applicable when the behavioural
phenotype has emerged more recently (e.g. during the development of modern dog breeds).
This method is less suitable for analysing behavioural differences between closely related dog breeds.
Opportunities: the method is especially suitable for meta-analyses, where already existing, large data sets
from robust behavioural assessments can be compared with ancestry-based, between-breed relationships
(i.e. genetic distances between breeds; distinct cladesof breeds).
Threats: the behavioural phenotype should be carefully selected, as in some cases, recent functional breed
selection can represent a serious confounding factor. Dog breeds with similar inclination for doghuman
interactivity levels (e.g. cooperative versus independent working dog breeds) can exist in distant genetic
clades.
Over-representation of particular breeds in the sample, or when the sample consists of only a few dog breeds,
can bias the results as this magnies the impact of potential confounding (non-ancestry-related) factors.
Convenience
sampling
(popular
breeds)
Strengths: this method is the easiest to apply because no dog breeds have to be excluded from the analysis.
The sample usually represents the dog population well in a given area and time.
Weaknesses: differences are difcult (and often at best tentative) to associate with explanatory variables.
The ad-hoc breed assortment in the sample may even conceal breed- or breed group-related differences that
would be possible to detect with a hypothesis-driven approach.
Opportunities: this is a good method for exploratory investigations, where, for example, the presence
absencestatus of particular behaviours is of interest.
The method is also suitable for assessing the preferences, experiences, or opinions of respondents about dog
breed-related behavioural phenomena.
Threats: even with inclusion of numerous breeds in the sample, there is a strong chance that various
confounding variables (e.g. functional breed selection, genetic relatedness/distance, housing conditions,
training level, etc.) will impact the results.
Convenience sampling should not be used to draw conclusions which would only be possible after hypothesis-
driven breed choice.
Biological Reviews 100 (2025) 6884 © 2024 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
Behaviour of dog breeds 79
Dobos & Pongracz, 2023). This method is less suitable for
analysing behavioural differences between closely related
breeds (Dorey et al., 2009).
Functional sampling is based on biologically relevant
hypotheses, and should result in valid conclusions if a wide
variety of breeds is tested (Bognar et al., 2021). As indepen-
dentand cooperative