I need help with a Biology question. All explanations and answers will be used to help me learn.1 What is the objective of the study?
2 Materials and Methods:
a What is the sample or evidence used?
b What are the specific studies/research performed if any?
c Describe geographic location of the sample or evidence used.
3 What are the results of the study?
4 What are the conclusions reached?
5 How is the study contributing to our knowledge of the subject?
6 Are there stated limitations in the particular study?
7-Does the article answer or contribute to any of the main questions regarding dog
domestication including: when, where, or how?
a According to current evidence (archaeological/biological), when was dog
domestication first practiced?
b Is there convincing evidence to where domestication was first practiced?
c Are there studies that support some particular theories explaining the probable
processes that may have ‘produced’ domestication?
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Testing the myth: tolerant dogs and
aggressive wolves
Friederike Range1,2, Caroline Ritter2 and Zsófia Virányi1,2
Cite this article: Range F, Ritter C, Virányi Z.
2015 Testing the myth: tolerant dogs and
aggressive wolves. Proc. R. Soc. B 282:
Received: 31 January 2015
Accepted: 30 March 2015
Subject Areas:
behaviour, evolution, cognition
agonistic behaviour, aggression, tolerance,
dominance, domestication
Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine, Vienna, Medical
University of Vienna, University of Vienna, Veterinaerplatz 1, 1210 Vienna, Austria
Wolf Science Centre, Dörfles 48, 2115 Ernstbrunn, Austria
Cooperation is thought to be highly dependent on tolerance. For example, it
has been suggested that dog–human cooperation has been enabled by selecting dogs for increased tolerance and reduced aggression during the course
of domestication (‘emotional reactivity hypothesis’). However, based on
observations of social interactions among members of captive packs, a few
dog–wolf comparisons found contradictory results. In this study, we compared intraspecies aggression and tolerance of dogs and wolves raised and
kept under identical conditions by investigating their agonistic behaviours
and cofeeding during pair-wise food competition tests, a situation that has
been directly linked to cooperation. We found that in wolves, dominant and
subordinate members of the dyads monopolized the food and showed agonistic behaviours to a similar extent, whereas in dogs these behaviours were
privileges of the high-ranking individuals. The fact that subordinate dogs
rarely challenged their higher-ranking partners suggests a steeper dominance
hierarchy in dogs than in wolves. Finally, wolves as well as dogs showed only
rare and weak aggression towards each other. Therefore, we suggest that
wolves are sufficiently tolerant to enable wolf–wolf cooperation, which in
turn might have been the basis for the evolution of dog–human cooperation
(canine cooperation hypothesis).
1. Introduction
Author for correspondence:
Friederike Range
e-mail: friederike.range@vetmeduni.ac.at
Electronic supplementary material is available
at http://dx.doi.org/10.1098/rspb.2015.0220 or
via http://rspb.royalsocietypublishing.org.
Cooperation within as well as across species has been suggested to correlate
with high tolerance and low aggression towards group members [1,2], independently of cognitive abilities [3,4]. Similarly, in domestic dogs cooperation with
humans is thought to be facilitated by their tameness and tolerant temperament
[5– 7]. Dogs are often considered to be a more docile and affectionate, juvenile
version of wolves [8– 10], and indeed, among human-raised wolves and dogs,
the latter seem better at inhibiting their agonistic behaviours and cooperating
with humans [11]. Although this increased tolerance in dog– human interactions is probably facilitated by socialization by humans and lifelong
experiences of relaxed interactions with them [12], various hypotheses suggest
that during domestication dogs have also been selected for reduced aggression
and fear in comparison with wolves [5,11,13].
Although this view of dogs having a more tolerant and less aggressive temperament than wolves is based mainly on human –animal interactions, Hare
et al. [14] have argued that dogs are more tolerant and less aggressive than
wolves also when interacting with conspecifics (p. 574; see also [15]). Most
other domestication hypotheses remain unclear as to whether they expect the
behaviour of dogs to be driven by more tolerant motivations specifically
when interacting with humans or whether they see reduced aggressiveness as
a general characteristic of dogs that can be expected also in intraspecific contexts. All domestication theories, however, seem to ignore earlier comparisons
where apparently contradictory behaviours have been observed in dog and
wolf packs. Based on observations of spontaneous social interactions of captive
dog and wolf packs raised under identical conditions, dogs of various breeds
& 2015 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution
License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original
author and source are credited.
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(a) Subjects
All wolves (n ¼ 9) that participated in this study originated from
North America but were born in captivity. The dogs (n ¼ 8) were
mongrels born in animal shelters in Hungary. For sex, age, relatedness and pack assignment refer to table 1. Data were collected
from August to December 2009 (wolves) and from April to July
2011 (dogs). In the middle of data collection (on 10 October,
when the young animals were five months old) the two packs
of wolves were integrated. The dogs lived in stable packs over
the entire testing period.
age at
After two months of data collection, the young wolves (pack 1) were
integrated with three older wolves (pack 2).
All of the animals were hand-raised in a comparable way in
peer groups at the Wolf Science Center (WSC) after being separated from their mothers in the first 10 days after birth. All
animals were integrated with adult animals into different packs
when four to six months old, but contact with humans was maintained in the form of daily training and behavioural test sessions
(see [27] for details on the raising procedure).
(b) Observations
To define the dominance relationships of the animals, we coded
submissive and dominant behaviours of the animals from videos
of their spontaneous social interactions that were recorded in
each pack during the respective testing period. Videos were
coded using all occurrence sampling and the WSC ethogram
(table 2). Video recordings were randomly distributed over
light hours (between 6.00 and 20.00) with at least 2 – 3 days
between them, and were only collected when all members of
the packs were present and no disturbance occurred (e.g. pack
visits, visitors in the park). A total of 12 videos of pack 1 (5 h
52 min), 18 videos of pack 1 þ 2 (after wolf pack formation;
22 h 12 min), 11 videos of pack 3 (5 h 45 min) and 20 videos of
pack 4 (3 h 49 min) were analysed.
(c) Experimental set-up
Each animal was tested with each of its pack members in a testing room (3 4 m) one to three times in each of the following
two conditions:
(1) Meat condition: pieces of raw meat were spread over a large
bowl (size was varied according to the size of the animals;
wolves: 40 cm diameter; dogs: 20 cm diameter). While the
Proc. R. Soc. B 282: 20150220
2. Material and methods
Table 1. List of animals, indicating genetic relationships (litters), sex
(M, male; F, female), age at testing and pack numbers.
have been shown to develop more intense aggression than
wolves, with serious fights occurring more often in dogs in
contrast to the ritualized agonistic behaviours of wolves
[9,16 –18]. This is so despite the fact that, although in some
breeds aggression against strangers has probably been and
still is an important basis for selection, wolves appear more
aggressive than dogs in intergroup interactions. While feral
dog groups rarely engage in physical aggression upon meeting [19,20], and only one single case has been described when
an out-group dog was killed after entering the territory of
another group [21], aggression of wolves towards non-pack
members along the border of their territories can be extreme
[22] and is one of the major mortality factors for wolves (after
humans) [22,23]. However, within-group aggression and
aggression towards out-group members have different functions, and are typically not correlated (see [24] for an
intensive discussion).
In this study, we set out to compare tolerant and agonistic
behaviours of wolves and dogs towards their pack-mates
during cofeeding, a situation that has directly been linked to
cooperation in other species. For instance, Hare et al. [25]
found that dyads of bonobos (Pan paniscus) were significantly
more likely to cofeed and cooperate than pairs of chimpanzees
(Pan troglodytes). The difference in tolerance was especially pronounced if the food was placed in a single, monopolizable
dish, and while this difference was not reflected in a higher
number of aggressive behaviours in chimpanzees compared
with bonobos, the authors reported that chimpanzees
seemed to avoid each other, whereas bonobos were at ease
with the partner (p. 619), which was attributed to a higher
mutual tolerance in bonobos. A similar link between
cooperation and tolerance has also been reported in macaque
species [26]. Less tolerant species, in which dominant animals
show more agonistic behaviours towards their subordinate
group-mates in a unidirectional manner, appear less cooperative than more tolerant species, characterized with aggression
of a lower intensity and a more balanced distribution.
Accordingly, we set out to make a similar comparison of
tolerance, a prerequisite for successful cooperation, in dogs
and wolves by testing dyads of pack-living dogs and
wolves raised and kept under identical conditions, when
being fed with either a single bowl of meat pieces or a
large bone. Both kinds of food could be shared as well as
easily monopolized, although only the bone could be taken
away. During the tests, we analysed not only the amount of
food monopolization, cofeeding and agonistic behaviours,
but especially their distribution over the subordinate and
dominant members of the dyads in order to compare the
tolerance of dogs and wolves.
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Table 2. Definitions of dominant and submissive behaviours used to define rank relationships.
to straighten up to full height, with a rigid posture and tail, possibly with raised hackles, ears erect and tail perpendicular
or above the back
stand over
to stand over another’s body, with all four paws on the ground; receiver may have either the whole body or just the
forepaws under the actor’s belly/side; tail held high
paw on
ride up (ru)
to place one or both forepaws on the other’s back
to mount another one from behind or from the side, exhibiting a thrusting motion
head on (ho)
the subject approaches another’s shoulder/back and puts its head on it; most times formation looks like a capital ‘T’
muzzle bite (mz)
to grab the muzzle of another subject either softly or with enough pressure to make the other whimper
to lower the head, sometimes bending the legs, arching the back, lowering the tail between the hind legs and avoiding
eye contact
passive submission
to lie on the back showing the stomach and holding the tail between the legs. The ears are held back and close to the
active submission
head and the subject raises a hind leg for inguinal presentation
the subject has its tail tucked between the hind legs sometimes wagging it while it is in a crouched position (with
hindquarters lowered) and may attempt to paw and lick the side of actors’/aggressor’s muzzle; the behaviour may
include urination
play submissive
approach submissive
to play with the tail between the hind legs, often running away and snapping at the other
to slowly approach another animal within one body length and remain within that distance for at least 5 s; the approach is
characterized by a ducked posture and tail between the legs; subject may move also in a wavy line and in a hesitant
(stop– start) manner
to move away slowly from another animal, displaying a submissive posture, having been threatened or attacked, or having
submissive avoidance
had a fight
in response to another reducing the distance towards it, the subject moves away displaying a submissive posture; the
subject may also look at the individual he is trying to avoid
in response to being approached by another animal, the subject moves out of its way or changes his direction to move
away from the approaching animal
being supplanted
in response to being approached by another animal, the subject leaves the place it has been interested in and moves away
bowls were large enough to allow subjects to eat from the
same bowl simultaneously, they were also small enough so
that an animal could easily monopolize it. The food could
not be carried away.
(2) Bone condition: one single large bone (20–30 cm) was provided.
Although it was large enough for more than one animal to chew
on it simultaneously, the subjects had the opportunity to carry it
away and could easily protect it.
Each trial lasted for a maximum of 5 min. Each animal was
tested only once per day. Conditions and combinations of dyads
were counterbalanced across and between all individuals within
a pack. In order to make sure that we tested only dyads in
which the animals had enough time to establish a stable relationship, the wolves were tested only with their original pack-mates
also after the two wolf packs were integrated (table 1). All experimental trials were videotaped from outside of the testing room
in order to avoid any disturbance of the animals.
(d) Procedure
To ensure that both animals were at the same distance from the
food resource at the beginning of the experimental trial, the food
was covered with a square wooden box (45 45 cm, 15 cm
height) that could be lifted from outside of the room using a
string-pulling system. Before the experiment, all animals were
habituated to the wooden box, first by placing it into their
living enclosure for two weeks and second by letting the animals
individually meet the moving box in the experimental room. At
this stage, food was hidden under the box, thus the animals
could also learn that they could get access to the food once the
box was lifted. Once the animals showed no hesitation to
approach the box in these individual trials, they proceeded to
the testing phase.
Each test trial started with placing the food in the middle of
the room and covering it with the wooden box. After this, the
two subjects were allowed to enter the room and one experimenter started to record all interactions with a hand-held
video camera. Once both animals were standing next to the
wooden box (within one body length) with their heads turned
towards the box, a second experimenter pulled the box up to
the ceiling. The test was terminated when the food was consumed or after 5 min.
(e) Analyses
The dominance ranks for individuals in each pack were calculated based on the number of their submissive and dominant
Proc. R. Soc. B 282: 20150220
stand tall
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Table 3. Definitions of agonistic behaviours coded in the tolerance tests.
higher rank
lower rank
to assume a threatening posture: pointing,
staring, curling the lips, baring the
canines, raising the hackles, snarling,
growling and barking, sometimes holding
the tail perpendicularly or above the back
to walk towards another wolf with piloerect,
stiff forelegs and ears back
to run or jump towards another animal with
tail, ears and sometimes hackles up, often
biting at the neck or muzzle, forcing it on
ground and holding it there
to strike another wolf sharply with the chest
or shoulder so that the other one falls to
the ground
to grab another one at the neck or at the
muzzle, forcing it down to the ground and
holding it there
a general term for high-intensity, aggressive,
often damaging encounters
to run after a conspecific, usually with ears
back and piloerect
to move quickly forward and bite by closing
the jaws and the teeth on another,
possibly accompanied by showing the
teeth and eventually growling and barking
to snap into the air with the flew up so that
the teeth are visible
behaviours (see table 2 for definitions) shown towards other pack
members. We used one interaction to establish directionality in
any dyad. Individuals were ordered to reduce the number of circular triads [28]. When a relationship between two individuals
was unclear, that pair was omitted from the analyses. See the
electronic supplementary material for dominance matrices.
Behavioural data collected during the tolerance tests were
extracted and analysed using the OBSERVER software (v. 5.0;
Noldus Information Technology). From the videotapes, for
each individual in each test, we coded the likelihood (0/1)
and/or the relative duration of silent cofeeding (i.e. feeding at
the same resource without aggressive signals), cofeeding with
agonistic signals (i.e. feeding at the same resource while mildly
threatening the partner by staring, growling, curling the lips,
baring the canines, raising the hackles, snarling, growling and
barking, sometimes lifting the tail perpendicularly or above the
back), agonistic behaviours (table 3) and feeding alone (i.e. the
subject was feeding without the partner at the resource).
All test videos were analysed by an independent coder. To confirm scoring consistency, 20% of the videos were coded by a second
coder. Spearman’s rank correlations (r) were in general high
(test duration: 0.99; total number of agonistic interactions: 0.81;
duration of cofeeding with agonistic signals: 0.85; duration of
non-communicative cofeeding: 0.92; duration of feeding alone: 0.81).
Figure 1. Relative duration ( percentage of trial duration; maximum 300 s) of
individuals feeding alone (if the behaviour occurred) dependent on their
dominance status in the tested dyad (high/low). Boxes represent the interquartile range, bars within boxes are median values and whiskers indicate
the 5th and 95th percentiles.
We analysed whether species, test condition (meat or bone), age
(in months) and dominance status of the subject (higher- or lowerranked member of the dyad) influenced the occurrence of tolerant
and agonistic cofeeding, feeding alone, and the relative duration
of these in the animals that did show the respective behaviours, as
well as the relative number of agonistic behaviours. To analyse
the occurrence of behaviours, we calculated a generalized linear
mixed-effect model (GLMM) using a binomial distribution. The
relative duration of the respective behaviours (in the case of silent
and agonistic cofeeding only when it occurred) were calculated
using linear mixed-effect (LME) models. Since the residuals were
not normally distributed, we used square root transformation in
the case of agonistic cofeeding, silent cofeeding and feeding
alone. In all models, the focal identity and the dyad were included
as random effects. The statistical analyses were performed using
the program R v. 2.15.2. [29]. All data are provided in the electronic
supplementary material.
3. Results
(a) Monopolization of food resource
We found an interaction between species and dominance
status in the likelihood as well as in the relative duration of
feeding alone (likelihood: GLMM: z ¼ 2.196, p ¼ 0.028; relative duration: LME: F1,74 ¼ 14.908, p , 0.001; figure 1).
While higher-ranked dogs were more likely to feed alone
and did so longer than lower-ranked dogs (likelihood:
GLMM: z ¼ 23.854, p , 0.001; relative duration: LME:
F1,28 ¼ 39.787, p , 0.001), in the wolves we found no influence of rank on the likelihood and duration of feeding
alone (likelihood: GLMM: z ¼ 21.43, p ¼ 0.15; relative duration: LME: F1,47 ¼ 0.41, p ¼ 0.52). In addition, we found an
interaction between dominance status and condition in the
likelihood and duration of feeding alone (likelihood:
GLMM: z ¼ 2.218, p ¼ 0.027; relative duration: LME:
F1,200 ¼ 9.669, p ¼ 0.002). Higher-ranked individuals were
more likely to feed alone and did so longer in the bone
than in the meat condition (likelihood: GLMM: z ¼ 22.793,
p ¼ 0.005; relative duration: LME: F1,98 ¼ 41.277, p , 0.001).
Lower-ranked individuals showed no difference in the
likelihood to feed alone; however, they did so for longer in
Proc. R. Soc. B 282: 20150220
percentage of feeding alone (%)
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Figure 2. Frequency of agonistic behaviours (1/s) in the two species according to the individuals’ dominance status in the (a) bone and (b) meat condition. Boxes
represent the interquartile range, bars within boxes are median values and whiskers indicate the 5th and 9th percentiles.
the bone than in the meat condition (likelihood: GLMM: z ¼
0.25, p ¼ 0.81; relative duration: LME: F1,98 ¼ 5.967, p ¼ 0.016).
Furthermore, we found no influence of age on the occurrence
and the duration of feeding alone (likelihood: GLMM: z ¼
3.59, p ¼ 0.11; relative duration: LME: F1,61 ¼ 0.05, p ¼ 0.82).
(b) Agonistic behaviours
Owing to interactions between species and age (GLMM: z ¼
2.860, p ¼ 0.004), between species and dominance status
(GLMM: z ¼ 3.464, p ¼ 001), and between species and condition (GLMM: z ¼ 2.287, p ¼ 0.022), we analysed agonistic
interactions in the two species separately. In the dogs, we
found no difference between the two conditions (GLMM:
z ¼ 0.94, p ¼ 0.35), and no influence of age (GLMM:
z ¼ 21.31, p ¼ 0.19), but more agonistic behaviours in the
higher- than lower-ranked animals (GLMM: z ¼ 25.350,
p , 0.001; figure 2). In the wolves, we found an effect of
age on the relative number of agonistic behaviours (GLMM:
z ¼ 2.723, p ¼ 0.006). The younger animals showed more
agonistic behaviours than the older ones. Furthermore, we
found more agonistic behaviours in the meat than in the
bone condition (GLMM: z ¼ 5.811, p , 0.001), however, we
found no influence of dominance status (GLMM:
z ¼ 20.28, p ¼ 0.78). Beyond the distribution of agonistic
behaviours, it is worthwhile to note that neither the wolves
nor the dogs were very aggressive during testing: agonistic
interactions occurred only in 84 of the 260 test sessions
(dogs: 36/134; wolves: 48/126). Moreover, of the 92 agonistic
behaviours in dogs, 73 were threats, while of the 185 agonistic
behaviours observed in wolves, 162 were threats.
(c) Silent cofeeding
Regarding tolerant behaviours, silent cofeeding was not influenced by status (likelihood: status: GLMM: z ¼ 20.15, p ¼
0.88; relative duration: LME: t115 ¼ 21.22, p ¼ 0.22). However,
in the likelihood, we found an interaction between species and
condition (GLMM: z ¼ 2.953, p ¼ 0.003). While wolves and
dogs behaved similarly in the meat condition (GLMM:
z ¼ 20.18, p ¼ 0.86), dogs were more likely to silently cofeed than wolves in the bone condition (GLMM: z ¼ 25.208,
p , 0.001). In general, silent cofeeding occurred for longer in
the meat than in the bone condition (LME: t120 ¼ 20.717, p ,
0.001). While age had no influence on the likelihood of silent
cofeeding (age: GLMM: z ¼ 1.87, p ¼ 0.06), we found an interaction between species and age in the duration of silent
cofeeding (LME: t13 ¼ 23.529, p ¼ 0.004). While we found
no influence of age in dogs (LME: t6 ¼ 0.63, p ¼ 0.55), in
wolves the older ones showed longer silent cofeeding than
the younger ones (LME: t7 ¼ 22.995, p ¼ 0.020).
(d) Cofeeding with agonistic signals
We found an interaction between species and status in the
likelihood that the behaviour occurred (GLMM: z ¼ 2.703,
p ¼ 0.007), with dominant dogs being more likely to cofeed
aggressively than lower-ranking individuals, but with no
difference between higher- and lower-ranking wolves
(GLMM: dog: z ¼ 22.620, p ¼ 0.009; wolf: z ¼ 0.70, p ¼
0.47). Moreover, while status did not influence the relative
duration of cofeeding with agonistic signals in wolves
(LME: F1,23 ¼ 0.14, p ¼ 0.71), the behaviour only occurred in
higher ranked dogs. Furthermore, the likelihood of agonistic
cofeeding was only influenced by condition in the wolves,
which cofed more often in the meat than in the bone condition (GLMM: wolf: z ¼ 2.531, p ¼ 0.011; dog: z ¼ 0.37, p ¼
0.71). In general, if cofeeding occurred, agonistic cofeeding
lasted longer in wolves than in dogs (LME: F1,38 ¼ 17.821,
p , 0.001), and all, wolves and dogs, cofed for longer in the
meat than in the bone condition (LME: F1,38 ¼ 9.176, p ¼
0.004). Finally, we found no influence of age on the occurrence or on the duration of agonistic cofeeding (likelihood:
GLMM: z ¼ 1.37, p ¼ 0.17; relative duration: LME: F1,37 ¼
0.18, p ¼ 0.67).
4. Discussion
To summarize, our results suggest that wolves are more tolerant than dogs because in wolves low- and high-ranking
animals monopolized the food and showed agonistic behaviours to a similar extent in contrast to dogs, where food
monopolization and threatening the partner were privileges
Proc. R. Soc. B 282: 20150220
relative no. agonistic behaviour
higher rank
lower rank
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Proc. R. Soc. B 282: 20150220
wolves to agonistic behaviours of their conspecifics. In this
case, even if dogs and wolves do not differ in the frequency
and intensity of aggression, dogs can be intimidated more
easily than wolves, and consequently will be likely to learn
to avoid potential conflicts during their development. If so,
the less tolerant behaviour of dogs compared with wolves
could reflect a more sensitive temperament rather than a less
tolerant one. Further studies, comparing the early agonistic
interactions of dog and wolf pups, are needed to clarify if
either or both of these two explanations are correct.
Before making any conclusions about fundamental differences in the social temperament of dogs and wolves, it is
important to realize that other differences between dogs and
wolves may also explain their differently tolerant behaviour.
First, domestic dogs may handle competitive situations
around resources on a case-by-case basis by using violence
to establish control rather than by relying on the dominance
relationships of the interacting partners. This is unlikely,
however, given that in free-ranging dogs dominance relationships remain stable across different competitive contexts, and
access to food resources is predicted reasonably well by the
rank positions of the individuals, with high-ranking individuals having priority of access [32] (see also [33,34]). Stable
dominance hierarchies have also been reported for groups
of pet dogs [35,36]. Moreover, according to this hypothesis,
the agonistic behaviours shown by each of our dogs should
be independent of their social rank. By contrast, our results
showed that the dominant dogs showed more agonistic behaviours than the subordinates. One can, however, still argue
that instead of a functional relationship between the two,
dominance rank and showing agonistic behaviours to a
partner simply correlate across individuals in dogs.
Second, Feddersen-Petersen [30] suggested that visual
communication in dogs is somewhat impaired due to their
reduced visual (facial as well as bodily) expression caused
by their altered morphology (fur colouring and length,
head shape, hanging ears, lack of tail, etc.; see also [37]). As
a consequence, this impairment might lead to an inability
to control conflicts at close quarters, which might appear to
the observer as if the dogs had a higher motivation to initiate
and escalate conflicts, while in truth they just have no means
to communicate properly with each other, and thus to deescalate conflicts. In this study, we used the same ethogram
to code the behaviour of the dogs and of the wolves. While
dogs showed all behaviours except knock-down, bite and
snapping, wolves did not ‘pin’ or ‘fight’ (for definitions see
table 3). Nevertheless, although dogs and wolves seem to
use the same signals overall, it is possible that dogs do not
use them as appropriately as wolves.
Whichever mechanistic explanation (less tolerant or more
sensitive temperament, impaired signalling, or non-functional
dominance hierarchy) is true, our and former observations that
domestic dogs show a less tolerant behaviour towards their
group-mates and express a steeper dominance hierarchy
than wolves in a feeding context nicely fit the social ecology
of wolves and dogs. While free-ranging domestic dogs have
retained some similar behavioural patterns (e.g. living in
pack-like groups and forming stable hierarchical structures
[32,34]), they differ from wolves in several aspects. For
example, they are not organized as family units but rather as
multi-male/multi-female groups of largely unrelated individuals. Accordingly, female dogs usually raise their offspring
alone or with limited help from the father [38]. Moreover,
of the high-ranking members of the dyads. In contrast to the
subordinate wolves, which readily challenged their dominant
partners (e.g. with agonistic signals during cofeeding), the
low-ranking dogs cofed only silently and readily retreated
when rebuked by the dominant partner. In sum, in our captive
packs, wolves behaved tolerantly to their pack members
during feeding, in contrast to the dogs, which have a steeper
and more rigid dominance hierarchy. At the same time, however, dogs and wolves proved to be similar in their agonistic
behaviour, displaying mostly threatening signals and even
those in only one third of the tests.
As mentioned briefly in the introduction, similar differences in the distribution of agonistic behaviours over
low- and high-ranking animals have also been described
between other closely related species. More specifically,
based on their agonistic behaviour, tolerance, conciliatory
behaviour, dominance gradient and kin bias, Thierry [26]
arranged macaque species according to a four-grade scale.
The first grade is characterized by unidirectional aggression
of dominant animals, with high and severe biting rates, and
subordinates generally fleeing or submitting when attacked.
The species belonging here are characterized as having a
steep dominance hierarchy and a low tolerance level. At the
other extreme of the scale, the intensity of aggression and
the biting rate are low, and most agonistic interactions are
bidirectional, meaning that the victim of aggression protests
or counter-attacks. In these species, the dominance gradient
is less steep and tolerance is high. Thus, while the asymmetry
of contests and the dominance gradient decrease from the
first to the fourth grade, social tolerance increases. In accordance with Thierry’s [26] categorization, based on our results
dogs would be characterized as less tolerant than wolves.
As we tested a relatively low number of animals living in
few packs at the same facility, one may question to what
extent these findings are representative for wolves and dogs
in general. Importantly, earlier observations on human-raised
wolves and dogs by Frank & Frank [9] and Feddersen-Petersen
[17,30] also reported more fierce intraspecific aggression in
young dogs than in young wolves.
One may argue, however, that our results reflect rather
the young age of our subjects than a more fundamental
difference in the tolerance of dogs and wolves. Domestication
is thought to accelerate sexual maturation [31], and accordingly, wolves are usually considered to reach sexual
maturity later than dogs. One might argue that higher tolerance in our wolves may reflect their lack of maturation.
Testing older animals would indeed be important, and one
may expect them to be more aggressive. However, our findings, although on a small sample (we had only three
wolves in the older age group), contradict this expectation:
older wolves were more likely to feed together silently than
the younger wolves, suggesting that tolerance actually
increased with age rather than decreased.
Therefore, the question remains why dogs behave less tolerantly towards their conspecific pack-mates than wolves.
First, the steeper dominance hierarchy of dogs may result
from their higher intraspecific aggressiveness compared with
wolves, as suggested by earlier observations [9,17,30]. More
frequent or more intensive aggression in dog packs than
wolf packs may reflect a less tolerant temperament of dogs
than of wolves, which would be in sharp contrast with suggestions of the domestication hypotheses [11,14]. Alternatively or
additionally, however, dogs may also be more sensitive than
Downloaded from http://rspb.royalsocietypublishing.org/ on June 8, 2015
Acknowledgements. We thank Stefanie Heufelder and Christina Mayer for
conducting part of the tolerance tests and collecting the behavioural
data. Furthermore, we thank Sarah Marshall-Pescini, Rachel Dale,
Kurt Kotrschal, Enikö Kubinyi and five anonymous referees for comments on an earlier draft of the manuscript, Marianne Heberlein for
the statistical support, and many students and volunteers for their
devotion and assistance with raising the animals.
Funding statement. The project received funding from the Austrian
Science Fund (FWF): P21244-B17, the European Research Council
under the European Union’s Seventh Framework Programme (FP/
2007– 2013)/ERC Grant Agreement no. 311870 and the WWTF
project CS11-026. Moreover, Z.V. was supported by the OTKA
project K84036. We further thank many private sponsors, including
Royal Canin for financial support and the Game Park Ernstbrunn
for hosting the WSC.
Authors’ contributions. F.R. conceived, designed and coordinated the
study, participated in data analysis and drafted the manuscript.
Z.V. helped designing the study, participated in data analyses and
helped draft the manuscript. C.R. collected the data, coded the
videos and did the initial statistical analyses. All authors gave final
approval for publication.
Scott MP. 2006 The role of juvenile hormone in
competition and cooperation by burying beetles.
J. Insect Physiol. 52, 1005 –1011. (doi:10.1016/j.
Werdenich D, Huber L. 2002 Social factors
determine cooperation in marmosets. Anim. Behav.
64, 771–781. (doi:10.1006/anbe.2002.9001)
Chalmeau R, Gallo A. 1993 Social transmission
among nonhuman-primates. Annee Psychol. 93,
427 –439. (doi:10.3406/psy.1993.28705)
Chalmeau R, Gallo A. 1996 Cooperation in primates:
critical analysis of behavioural criteria. Behav.
Processes 35, 101–111. (doi:10.1016/03766357(95)00049-6)
Hare B, Tomasello M. 2005 The emotional
reactivity hypothesis and cognitive evolution.
Trends Cogn. Sci. 9, 464 –465. (doi:10.1016/j.tics.
Clutton-Brock J. 1995 Origins of the dogs:
domestication and early history. In The domestic
dog: its evolution, behaviour and interactions with
Proc. R. Soc. B 282: 20150220
clarify (i) what explains this behavioural difference at a
mechanistic level, as well as (ii) to what extent it reflects different genetic predispositions in dogs and wolves, which are then
differently enlarged by developmental processes (e.g. socialization in differently tolerant social groups). As discussed
earlier, socialization in differently tolerant conspecific groups
can strongly influence the behaviour of adult animals, and
the behaviour of dogs that grow up in human families can
be even more strongly modified. Moreover, it is important to
note that the canine cooperation hypothesis is compatible
also with other evolutionary hypotheses that specifically
address the human-directed behaviour of dogs.
Still, we argue that studying the intraspecific social life of the
domestic dog can provide important information about the
effects of domestication by differentiating between general
characteristics of dogs and their other skills used only when
interacting with humans. Even more, we suggest that such
studies can give us a more complete insight into the social ecology of dogs, which has probably driven the evolution of their
social behaviour and the cognitive and emotional processes
underlying it. Living together with (or close to) humans, cooperating and communicating with them has certainly imposed
important adaptational demands on the evolution of dog
behaviour [50,51]. Beyond this, however, living in conspecific
groups and interacting with other dogs were always part of
the life of domestic dogs: pet dogs represent a small part of the
entire dog population, with current estimates suggesting that
free-ranging dogs represent about 76–83% of the global dog
population [52,53]. These millions of dogs live more or less independently from humans, in conspecific groups in which their
survival is greatly determined by successful communication
and social manoeuvring in intraspecific contexts [54].
dogs also differ from wolves in their foraging strategies, with
wolves relying heavily on hunting, while dogs often feed
on stable food resources provided by humans (e.g. scavenging at rubbish dumps or food provisioned by humans
[39,40]; but see [41]). It has been suggested that, in dogs,
this feeding ecology might have relaxed the need to feed
quickly, whereas wolves need to gorge food down to avoid
competitors (bears, ravens) taking away their food, and
thus cannot engage in conflicts over food. Alternatively,
this buffering effect of food provisioning by humans has
been proposed to reduce selection against intraspecific
aggression in dogs [9], which in turn might explain their
difficulties in cooperating with each other and resolving
social conflicts [17,30]. Interestingly, from 6 to 12 months of
age, dogs seem to be similarly aggressive to jackals adapted
to a more solitary life [17].
In contrast to the social system of free-ranging dogs, the
social life of wolves is characterized by the cooperation of closely related animals. The wolf pack is a family unit, where the
offspring from the previous year delay dispersal and help the
breeding pair(s) to raise their young [42,43]. Moreover, they
rely on close action coordination with pack members when
defending their kills [44] and territories, and hunting large
game [42,43]. Accordingly, selection has probably favoured
reduced aggression (by high tolerance, fine-tuned communication and a functional dominance hierarchy) towards close
kin, allowing them to cooperate closely with each other.
Consequently, if we relate our experimental findings on the
tolerance of wolves to the social ecology of wild-living packs,
we find the same link between tolerance and intraspecific
cooperation as in other species (e.g. [26,45]): wolves appear tolerant, attentive and at the same time cooperative towards their
pack members [42,46]. This view is also supported by our
recent results showing that wolves follow the gaze of conspecifics [47] and are more adept at socially learning from
conspecifics than dogs [27]. This view of wolves is in contrast
to the starting point of several recent domestication hypotheses
describing wolves as less cooperative than dogs [11,14].
Instead, we propose that wolves possess most of the skills
that have been suggested to be preconditions for successful
cooperation. Therefore, dog–human cooperation might have
evolved on the foundation of wolf–wolf cooperation (‘canine
cooperation hypothesis’ [27,48,49]). A first step might have
been that dogs lost their fear of humans and thus became
able to extend their relevant social skills to interactions with
them (see also [5]).
The social life of wild-living dog packs (as well as our and
former findings on the intraspecific social behaviour of captive
dog packs) show, however, that this could not all have been as
indicated by the less tolerant behaviour of dogs towards conspecifics in comparison to wolves. Further research has to
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40. Butler JRA, du Toit JT, Bingham J. 2004 Freeranging domestic dogs (Canis familiaris) as
predators and prey in rural Zimbabwe: threats of
competition and disease to large wild carnivores.
Biol. Conserv. 115, 369– 378. (doi:10.1016/S00063207(03)00152-6)
41. Manor R, Saltz D. 2004 The impact of free-roaming
dogs on gazelle kid/female ratio in a fragmented
area. Biol. Conserv. 119, 231– 236. (doi:10.1016/j.
42. Mech LD, Boitani L. 2003 Wolf social ecology. In
Wolves: behavior, ecology, and conservation (eds
LD Mech, L Boitani), pp. 1 –35. Chicago, IL:
University of Chicago Press.
43. Mech D. 1970 The wolf: the ecology and behaviour
of an endangered species. Garden City, NY: Natural
History Press.
44. Kaczensky P, Hayes RD, Promberger C. 2005 Effect
of raven Corvus corax scavenging on the kill rates of
wolf Canis lupus packs. Wildlife Biol. 11, 101 –108.
45. Petit O, Desportes C, Thierry B. 1992 Differential
probability of coproduction in two species of macaque
(Macaca Tonkeana M. Mulatta). Ethology 90, 107–120.
46. Zimen E. 1997 Der Wolf. Verhalten, Ökologie und
Mythos. München, Germany: Knesebeck & Schuler
GmbH & Co. Verlags KG.
47. Range F, Viranyi Z. 2011 Development of gaze
following abilities in wolves (Canis lupus). PLoS ONE
6, e16888. (doi:10.1371/journal.pone.0016888)
48. Range F, Virányi Z. 2013 Social learning from
humans or conspecifics: differences and similarities
between wolves and dogs. Front. Psychol. 4, 868.
49. Range F, Virányi Z. 2015 Tracking the evolutionary
origins of dog-human cooperation: the ‘Canine
Cooperation Hypothesis’. Front. Psychol. 5, 1582.
50. Miklosi A, Topal J. 2005 Is there a simple recipe for
how to make friends? Trends Cogn. Sci. 9, 463 –464.
51. Topal J, Miklosi A, Gacsi M, Doka A, Pongracz P, Kubinyi
E, Viranyi Z, Csanyi V. 2009 The dog as a model for
understanding human social behavior. Adv. Stud. Behav.
39, 71–116. (doi:10.1016/S0065-3454(09)39003-8)
52. Hughes J, Macdonald DW. 2013 A review of the
interactions between free-roaming domestic dogs
and wildlife. Biol. Conserv. 157, 341–351. (doi:10.
53. Lord K, Feinstein M, Smith B, Coppinger R. 2013
Variation in reproductive traits of members of the
genus Canis with special attention to the domestic
dog (Canis familiaris). Behav. Processes 92, 131–142.
54. Bonanni R, Cafazzo S. 2014 The social organisation
of a population of free-ranging dogs in a suburban
area of Rome: a reassessment of the effects of
domestication on dogs’ behaviour. In The social dog:
behaviour and cognition (eds J Kaminski,
S Marshall-Pescini), pp. 65 –104. Amsterdam, The
Netherlands: Academic Press.
Proc. R. Soc. B 282: 20150220
annual report, 2006. Yellowstone National Park, WY:
National Park Service, Yellowstone Center for Resources.
Virányi Z, Range F. 2014 On the way to a better
understanding of dog domestication: aggression
and cooperativeness in dogs and wolves. In The
social dog: behaviour and cognition (eds J Kaminski,
S Marshall-Pescini), pp. 35 –62. Amsterdam, The
Netherlands: Academic Press.
Hare B, Melis AP, Woods V, Hastings S, Wrangham R.
2007 Tolerance allows bonobos to outperform
chimpanzees on a cooperative task. Curr. Biol. 17,
619–623. (doi:10.1016/j.cub.2007.02.040)
Thierry B. 2000 Covariation of conflict management
patterns across macaque species. In Natural conflict
resolution (eds F Aureli, FBM De Waal), pp. 106 –
128. Berkeley, CA: University of California Press.
Range F, Virányi Z. 2014 Wolves are better imitators
of conspecifics than dogs. PLoS ONE 9, e86559.
Vries de H. 1995 An improved test of linearity in
dominance hierarchies containing unknown
relationships. Anim. Behav. 50, 1375–1389.
R Core Team. 2012.
Feddersen-Petersen DU. 2007 Social behaviour of
dogs and related canids. In The behavioural biology
of dogs (ed. P Jensen), pp. 105– 119. Wallingford,
UK: CAB International.
Trut L, Oskina I, Kharlamova A. 2009 Animal
evolution during domestication: the domesticated
fox as a model. BioEssays 31, 349–360. (doi:10.
Cafazzo S, Valsecchi P, Bonanni R, Natoli E. 2010
Dominance in relation to age, sex and competitive
contexts in a group of free-ranging domestic dogs.
Behav. Ecol. 21, 443–455. (doi:10.1093/beheco/
Pal SK, Ghosh B, Roy S. 1998 Agonistic behaviour of
free-ranging dogs (Canis familiaris) in relation to
season, sex and age. Appl. Ani. Behav. Sci. 59,
331 –348. (doi:10.1016/S0168-1591(98)00108-7)
Bonanni R, Cafazzo S, Valsecchi P, Natoli E. 2010
Effect of affiliative and agonistic relationships on
leadership behaviour in free-ranging dogs. Anim.
Behav. 79, 981 –991. (doi:10.1016/j.anbehav.2010.
Trisko RK. 2011 Dominance, egalitarianism and
friendship at a dog daycare facility. Ann Arbor, MI:
University of Michigan.
van der Borg JAM, Schilder MBH, Vinke C. 2013
Dominance and its behavioral measures in group
housed domestic dogs. J. Vet. Behav. 8, e27–e28.
Goodwin D, Bradshaw JWS, Wickens SM. 1997
Paedomorphosis affects agonistic visual signals of
domestic dogs. Anim. Behav. 53, 297–304. (doi:10.
Pal SK. 2005 Parental care in free-ranging dogs,
Canis familiaris. Appl. Anim. Behav. Sci. 90, 31 –47.
Schmidt PA, Mech LD. 1997 Wolf pack size and food
acquisition. Am. Naturalist 150, 513 –517. (doi:10.
people (ed. JA Serpell), pp. 199 –216. Cambridge,
UK: Cambridge University Press.
Coppinger R, Coppinger L. 2001 Dogs. A new
understanding of canine origin, behavior and evolution.
Chicago, IL: University of Chicago Press.
Fox MW. 1971 The behaviour of wolves, dogs and
related canids. London, UK: Jonathan Cape.
Frank H, Frank MG. 1982 On the effects of
domestication on canine social development and
behavior. Appl. Anim. Ethol. 8, 507–525. (doi:10.
Lindsay SR. 2008 Handbook of applied dog behavior
and training, procedures and protocols. New York,
NY: Wiley.
Gacsi M, Gyori B, Viranyi Z, Kubinyi E, Range F,
Belenyi B, Miklosi A. 2009 Explaining dog wolf
differences in utilizing human pointing gestures:
selection for synergistic shifts in the development of
some social skills. PLoS ONE 4, e6584. (doi:10.1371/
Udell MAR, Dorey NR, Wynne CDL. 2010 What did
domestication do to dogs? A new account of dogs’
sensitivity to human actions. Biol. Rev. 85, 327–
345. (doi:10.1111/j.1469-185X.2009.00104.x)
Miklosi Ã. 2008 Dog behaviour, evolution, and
cognition. Oxford, UK: Oxford University Press.
Hare B, Wobber V, Wrangham R. 2012 The selfdomestication hypothesis: evolution of bonobo
psychology is due to selection against aggression.
Anim. Behav. 83, 573–585. (doi:10.1016/j.anbehav.
Ostojic L, Clayton N. 2014 Behavioural coordination
of dogs in a cooperative problem-solving task with
a conspecific and a human partner. Anim. Cogn. 17,
445–459. (doi:10.1007/s10071-013-0676-1)
Feddersen-Petersen DU. 2004 Hundepsychologie.
Stuttgart, Germany: Kosmos.
Feddersen-Petersen DU. 1991 The ontogeny of
social play and agonistic behaviour in selected canid
species. Bonner zoologische Beiträge 42, 97 –114.
Zimen E. 1970 Vergleichende
Verhaltensbeobachtungen an Wölfen und
Königspudeln. Kiel, Germany: University of Kiel.
Boitani L, Francisci F, Ciucci P. 1995 Population
biology and ecology of feral dogs in central Italy. In
The domestic dog: its evolution, behaviour and
interactions with people (ed. J Serpell),
pp. 218 –245. Cambridge, UK: Cambridge
University Press.
Pal S, Ghosh B, Roy S. 1999 Inter-and intra-sexual
behaviour of free-ranging dogs (Canis familiaris).
Appl. Anim. Behav. Sci. 62, 267–278. (doi:10.1016/
Macdonald D, Carr G. 1995 Variation in dog society:
between resource dispersion and social flux. In The
domestic dog: its evolution, behaviour, and
interactions with people (ed. J Serpell), pp. 199–216.
Cambridge, UK: Cambridge University Press.
Mech D. 1994 Buffer zones of territories of gray
wolves as regions of intraspecific strife. J. Mammal.
75, 199–202. (doi:10.2307/1382251)
Smith DW, Stahler DR, Guernsey DS, Metz M, Nelson A,
Albers E, McIntyre R. 2007 Yellowstone Wolf Project:

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