Effect of sex and gonadectomy on dogs’ spatial performance
Abstract
In order to investigate the effect of sex and gonadectomy on dog’s spatial performance, 64 pet dogs were recruited until obtaining four equally sized groups, namely intact males (IM), orchiectomised males (OM), intact females (IF) and ovariectomised females (OF). Dogs were tested in a T-maze paradigm for their performance in learning the way out of the maze, recalling the learned exit after 2 weeks and reversing their learning right after. Sex had an effect on dogs’ speed and accuracy in the initial learning task, with IF reaching the learning criterion in fewer trials and making fewer errors than IM; IF also outperformed OF in terms of both speed of learning and accuracy in the learning task. No effect of orchiectomy was found in this stage of the experimental procedure. The better performance of IF was also evident in the percentage of success in both the learning and memory tasks, which were achieved by 100% of the IF, 69% of the IM, 62% of the OF and 56% of the OM. No effect of either sex or gonadectomy was found in the reversal learning task. Results are discussed within current views, which attribute sex-differences in spatial navigation to a sex dimorphism in the deployment of various types of information. In spite of the frequency with which dogs’ gonadectomy is advised in most western countries, its consequences on cognitive abilities remain virtually unknown and the present study provides the first evidence that ovariectomy does impact on dogs’ functions other than reproductive ones.
... Among cognitive abilities, spatial navigation has been one of the most studied for detecting sex differences in mammals (Healy et al. 2009;Saucier et al. 2008;Shah et al. 2014). Speci cally, males have been proven to outperform females in orientation in voles (Kavaliers et al. 1998), cervine mice (Kavaliers et al. 1996), mice (Berger-Sweeney et al. 1995), rats (Blokland et al. 2006) and humans (Saucier et al. 2002), although mixed results have been obtained in dogs (Fugazza et al. 2017; Mongillo et al. 2017;Scandurra et al. 2018). In females, spatial memory is functional for the care and growth of offspring, while in males it is more developed and shaped by sexual selection, leading them to compete for mating primarily through navigation in larger spaces (Pal et al. 1998;Shah et al. 2014). ...
Spatial navigation has been extensively investigated for detecting sex differences in mammals, and the domesticated guinea pig ( Cavia aperea porcellus ) serves as a promising species for such studies, due to distinct parental investment between the sexes. In our exploration of sex-related effects on spatial navigation, we focused on the learning performance and spatial strategy (allocentric or egocentric) employed by guinea pigs in a plus maze paradigm. Results show that 50% of the animals completed the spatial navigation test. Regarding sex differences, 24.2% of females completed the test, while the completion rate for males was significantly higher at 64%. Males achieved the learning criterion with a significantly lower number of trials compared to females, indicating superior spatial abilities in the plus maze paradigm. Like their wild counterparts, male domestic guinea pigs exhibited better spatial skills than females. However, we observed no sex difference in the preference of strategy or the latency of task resolution.
... Sin embargo, hasta el momento, la mayor parte de los estudios de reversión en esta especie se han centrado en su valor como indicador temprano de deterioro cognitivo (Piotti et al., 2018). En este línea, diversas evidencias muestran una fuerte asociación entre la edad y el desempeño en esta tarea, hallándose un deterioro en los perros mayores (e.g., Milgram et al., 1994;Mongillo et al., 2013;Mongillo et al., 2017;Piotti et al., 2018;Tapp, 2003;Van Bourg et al., 2021). Dada esta escasez de antecedentes, el presente estudio se propone indagar en la importancia de dos factores que podrían incidir en el aprendizaje de reversión: el entrenamiento en detección de olores y la presencia o ausencia de una clave social humana junto a una clave no social como estímulos discriminativos. ...
El aprendizaje de reversión requiere que los sujetos inhiban una respuesta preponderante a un estímulo previamente reforzado y que cambien su conducta hacia una nueva contingencia de estímulo-refuerzo. Este permite medir la flexibilidad y el control inhibitorio, habilidades cruciales para los perros altamente entrenados, como es el caso de los perros de detección de olores. El objetivo de este estudio fue determinar si el entrenamiento en tareas de detección modula el aprendizaje de reversión con y sin claves sociales humanas. Se comparó el desempeño de perros entrenados en detección con perros de familia no entrenados, en un paradigma de aprendizaje espacial, utilizando solo una discriminación de lugar (derecha-izquierda; tarea no social) y luego incorporando a la clave de lugar una clave social (posición del cuerpo del experimentador; tarea social). Los resultados muestran que no hubo diferencias entre grupos en ninguna de las dos tareas. Esto podría relacionarse con las características particulares de dicho entrenamiento. Asimismo, el desempeño fue mejor en la tarea social que en la no social durante la discriminación inicial, pero en la fase de reversión se observó el patrón inverso. Estas discrepancias pondrían en evidencia la importancia de la presencia de claves sociales humanas en los entrenamientos.
... Pet dogs growing up in our complex environment generally have ample learning opportunities of how to interact and communicate with humans, thus garnering experiences enhancing their cognitive skills, an ontogenetic process called "enculturation" [26]. Studies postulate an augmenting effect of domestication on the social skills of dogs in cooperative-communicative tasks [37] like a social walk with their owner, impacting on exploration behavior; on the other hand it has been argued that as a result of domestication dogs' spatial memory capacity has been reduced [38],. Our results reflect intraspecific movement variability, which has also been found in free ranging dogs (see Hudson et al., 2017; 2019: three roaming patterns "Stay-at-home dogs; "Roamer dogs" and "Explorer dogs"). ...
Human-dog attachment is a special relationship and has been studied from various perspectives. Attachment or social bonding has a positive effect on the psychological and physiological wellbeing of a dog owner, increasing physical health and quality of life. Attachment is idiosyncratic, induced by neuroendocrinological functions like an oxytocin increase after an interaction, but also based on subjective perceptions of the quality of bonding and relationship. Dog-owner attachment was measured in this study using the Lexington Attachment to Pets Scale in its validated German version as a tool to compare owner perception with factual movement data of their dog. The question posed was whether the perceived dog behaviour impacted on the attachment score as assessed through the LAPS. The authors could show that perceived problematical or unwanted conduct, like hunting behaviour, had a negative effect on LAPS scores whereas perceived obedient behaviour had a positive effect upon attachment. The authors found that actual walking data of the dogs were not in congruence with owner assessments. Thus, owner reports alone possibly will not be a sufficient measure of dog-human relationships and animal behaviour.
... The higher needs could have prompted intact dogs to concentrate more on the task presented, as it involved obtaining food, even if the same difference in requirement would have been expected also in female dogs. Although neuter status influenced dogs' performance in some tasks designed to evaluate social and spatial cognitive abilities (Hart, 2001;Mongillo et al., 2016Mongillo et al., , 2017Scandurra et al., 2018Scandurra et al., , 2019Watowich et al., 2020), the differences found in the present study are more likely to concern lower level mechanisms, such as attention or motivation, than cognitive abilities per se. In this regard, the difference being only among male dogs could be linked to castrated male dogs (with a shorter exposure to sexual hormones) being more fearful in response to unfamiliar situations and objects (McGreevy et al., 2018), such as that of the test. ...
Although quantity discrimination and the factors affecting it have been widely studied in the domestic dog using a variety of paradigms, little attention has been given to the possible effects of the used paradigm itself. In the present study, we employed a paradigm in which naïve companion dogs were repeatedly presented with a free choice between two quantities of food (2vs.4, more difficult comparison, and 1 vs.8, simpler comparison). Dogs did not undergo any previous training and could freely choose to feed from either plate. After the choice was made, the second plate was withdrawn without letting the dog to eat its content. We hypothesized that a preference for the larger quantity of food may emerge as a consequence of experiencing the experimental procedure, and may not be expressed by the dogs on their first choice (hypothesis 1). If so, rewards experienced in the first trial may affect behaviour on subsequent trials (hypothesis 2). Data were analysed using generalized linear mixed models. Both hypothesis 1 (general performance P<0.0001, i.e., above chance level; first choice P=0.06, i.e., chance level) and 2 (P=0.001) were confirmed by the experimental results. The difficulty of the numerical comparison and the neuter status of the dogs had a significant effect on the overall performance, but not on the first choice nor on the likelihood of redirecting after the first trial. The results suggest that domestic dogs are highly sensitive to the results of their experience and adjust their behaviour accordingly, even after one single event. Future studies may help to disentangle the role of the food seen vs. eaten by the dog and the possible role of unintentional human feedback after the first choice.
... Sex differences have long been reported in various species for several cognitive abilities, such as spatial cognition [1,2] and learning ability [3]. Similar cognitive differences between males and females have also been found in dogs [4][5][6][7], but only a few studies have investigated the topic so far. These sex-specific behavioral differences are likely the contact or other human-directed social behaviors [34]. ...
Sex differences in a variety of cognitive traits have long been reported in various species, including dogs. However, only a few canine studies have taken the possible effect of reproductive hormones into account. The aim of this study was to investigate the effects of sex and reproductive status of pet dogs (N = 1032) on two cognitive traits: inhibitory control and social cognition. Inhibitory control was assessed using the cylinder test, and the dogs’ tendency to initiate social contact with a human during a problem-solving situation was assessed using the unsolvable task. Female dogs had a significantly higher success rate in the cylinder test compared to males, and they spent significantly more time in human-directed behavior during the unsolvable task. In contrast, males spent significantly more time in independent behavior during the unsolvable task. Reproductive status had no significant effect on the results of the cylinder test or the unsolvable task. Our results showed that female dogs asked for more help/used a more cooperative strategy during a problem-solving situation and had greater inhibitory control compared to males. According to our results, it seems likely that these sex differences were not influenced to a large extent by reproductive hormones.
... Nonetheless, a recent review suggests that sex-based differences in some behavioral and cognitive traits of dogs remained quite unchanged from their ancestors (Cassidy et al. 2017), despite the reduced impact of natural and sexual selection (Scandurra et al. 2018b). For example, previous studies underlined a male advantage in flexibly using spatial information (Fugazza et al. 2016;Mongillo et al. 2017a;Scandurra et al. 2018c), which is an important requisite for male dogs since they range over significantly larger areas than females when free-roaming (Sparkes et al. 2014). Concerning the social sphere, male dogs show generally a higher degree of aggressiveness (Eken Asp et al. 2015;Pérez-Guisado et al. 2006), with the greatest likelihood of occurrence in males especially in contexts aimed to raise reproductive success (Borchelt 1983). ...
Sex differences in the behavioral responses of Labrador Retriever dogs in the Strange Situation Test were explored. Behaviors expressed by dogs during seven 3-min episodes were analyzed through a Principal Component Analysis (PCA). The scores of factors obtained were analyzed with a Generalized Linear Mixed Model to reveal the effects of the dog’s sex and age and the owner’s sex. In Episode 1 (dog and owner) and 5 (dog alone), the PCA identified three and two factors, respectively, which overall explained 68.7% and 59.8% of the variance, with no effect of sex. In Episodes 2 (dog, owner, and stranger), 3 and 6 (dog and stranger), and 4 and 7 (dog and owner), the PCA identified four factors, which overall explained 51.0% of the variance. Effects of sex were found on: Factor 1 (distress), with lower scores obtained by females in Episode 2 and higher in Episode 3; Factor 2 (sociability), which was overall higher in females; Factor 3 (separation-distress), with females, but not males, obtaining higher scores when left with the stranger than when with the owner. Therefore, females were overall more social but seemed more affected than males by the owner’s absence. Parallels can be traced between our results and sex differences found in adult human romantic attachment, suggesting that the dog-owner bond has characteristics that are not found in the infant-mother relationship.
... Pet dogs growing up in our complex environment generally have ample learning opportunities of how to interact and communicate with humans, thus garnering experiences enhancing their cognitive skills, an ontogenetic process called "enculturation" [26]. Studies postulate an augmenting effect of domestication on the social skills of dogs in cooperative-communicative tasks [37] like a social walk with their owner, impacting on exploration behavior; on the other hand it has been argued that as a result of domestication dogs' spatial memory capacity has been reduced [38],. Our results reflect intraspecific movement variability, which has also been found in free ranging dogs (see Hudson et al., 2017; 2019: three roaming patterns "Stay-at-home dogs; "Roamer dogs" and "Explorer dogs"). ...
... We found differences in some parameters related to performance between sexes: although females responded to more cues, at a faster speed, and with fewer repetitions, males wagged their tails for longer during the sessions. Males and females have been reported to excel in different tasks-males have shown greater performance in maintaining eye contact with experimenters and in short-term memory tests [58], whereas females were better at leaving a maze [59]. The inferior performance of males in our study may be related to their possibly lower trainability, as already reported [60]. ...
The inclusion of life history as a possible influential factor is pivotal in studies on behavior, welfare, and cognition. Shelter dogs have usually experienced a life involving poor social interactions with humans. Thus, we aimed to investigate the behavioral responses of shelter dogs (SDs) and companion dogs (CDs) during the training of two vocal cues (“sit”, “paw”), as well as the possible associations between their responses and the behaviors of trainers. We studied 15 SDs and 15 CDs in up to eight five-minute training sessions. Dogs’ and trainers’ behaviors were recorded and analyzed (through GLM, GLMM, correlation and Mann–Whitney tests). Shelter dogs responded to more cues per session, with shorter latencies and fewer repetitions of cues. Moreover, SDs spent more time wagging their tails. Dogs’ sex and trainers’ behaviors were also associated with differences in dogs’ responses. The use of a reproachful tone of voice was associated with a greater number of cues responded to, shorter latencies, and fewer repetitions of cues. However, this type voice/discourse was also linked to a greater exhibition of non-training behaviors (e.g., exploring the room or jumping on the trainer), and to dogs spending less time next to the trainer and wagging their tails. On the other hand, the use of a neutral tone of voice and laughter, besides being linked to performance, was also associated with longer durations of tail wagging. Furthermore, the duration of the trainers’ orientation to dogs was correlated with the orientation of the dogs to the trainers. Our data suggest that, even when having experienced social deprivation from humans, SDs’ capacities to learn vocal cues were preserved, possibly due to ontogenic homeostasis processes. Shelter dogs’ greater interest in the sessions may be also credited to their socially-deprived routine. Our outcomes also point to an association between friendly interactions during training and dog performance and excitement, which suggests that such interactions may have the potential to improve SD welfare.
We report an observational, double-blind study that examined puppies’ behaviors while engaged in solving an experimental food retrieval task (food retrieval task instrument: FRTI). The experimental setting included passive social distractors (i.e., the dog’s owner and a stranger). The focus was on how the social and physical environment shapes puppies’ behaviors according to sex. The dependent variables were the number of tasks solved on an apparatus (Performance Index) and the time required to solve the first task (Speed). Sex and Stress were set as explanatory factors, and Social Interest, FRTI interactions, other behavior, and age as covariates. The main findings were that male puppies solved the first task faster than females. On the other hand, females displayed significantly more social interest and did so more rapidly than males. Males showed delayed task resolution. This study demonstrates sex differences in a problem-solving task in dog puppies for the first time, thus highlighting that sexually dimorphic behavioral differences in problem-solving strategies develop early on during ontogenesis.
The Can de Palleiro (CP) is an autochthonous canine breed from Galicia (NW Spain). Interestingly, no previous research has been published about the behaviour of this breed. Thus, the aim of the present study was to obtain a deeper understanding of CP behavioural and temperamental traits and detect any potentially problematic behaviour by using the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) and the Socially Acceptable Behaviour (SAB) test. Behavioural information was obtained from 377 dogs—177 CPs and 200 general population (GP) dogs—using the C-BARQ. Additionally, 32 dogs were enrolled to perform the SAB test (19 CPs and 13 GP dogs) in order to directly evaluate their temperament. Our results indicated that CP dogs had a lower tendency to show aggressiveness towards their owners (0.18 times lower, p = 0.033) and less fear of other dogs (by 0.43 times, p = 0.001), as well as higher trainability levels (2.56 times higher, p < 0.001) when compared to GP dogs. CP dogs also had increased odds of showing chasing behaviour (3.81 times higher, p < 0.001). Conversely, CPs had reduced odds of non-social fear, separation-related problems and excitability (by 0.42, 0.35 and 0.48 times, respectively; p < 0.001, p < 0.001 and p = 0.002). The current research represents a starting point for the study of the behaviour of CPs, which appear to be a working breed, with guarding and, especially, herding characteristics.
Aged dogs spontaneously develop progressive decline in both cognitive and behavioral function, in addition to neuropathological changes, that collectively parallel several aspects of human aging and Alzheimer's disease progression and likely contribute to the development of canine cognitive dysfunction syndrome. In the current study, ethologically relevant spatial learning, retention, and reversal learning tasks were conducted, with the goal of expanding canine neuropsychological testing to pet dogs. Initially, dogs (N = 44, aged 7.8 ± 2.8 years, mean ± SD) had to learn which of two alternative routes successfully led out of a T-maze. Two weeks later, long-term memory retention was assessed, immediately followed by a reversal learning task in which the previously correct route out of the maze was reversed compared with the initial learning and memory retention tasks. No effects of age were evident on the learning or retention tasks. However, older (≥8 years) dogs were significantly impaired on the reversal learning task compared with younger ones (<8 years). Moreover, trial response latency was significantly increased in aged dogs across both the initial and reversal learning tasks but not on the retention task, which suggests that processing speed was impaired by increasing age during the acquisition of novel spatial information but not during performance of previously learned responses. Overall, the current study provides a framework for assessing cognitive function in pet dogs, which should improve understanding of the effects of aging on cognition in the dog population.
The present study investigated spatial memory in domestic dogs (Canis familiaris) through the use of a radial arm maze. The study consisted of a total of three separate experiments. In the first two experiments, the ability of the dogs to successfully remember previously unentered arms was evaluated. The third experiment was similar to the first two, but also examined the nature of the serial position effect. Performance in all three experiments was better than expected solely by random choices. Dogs showed a much better memory for spatial locations presented earlier in a spatial list compared with those presented in the middle. Based on the present results, we suggest that the radial arm maze assesses canine spatial memory and that dogs show a primacy effect.
In the context of dog training it would be of utmost importance to understand the mechanisms that control how attention to humans is allocated by dogs, and how this can be modified by training. This study aimed at characterising the patterns of attention paid to their handler by dogs with different training level, while performing typical obedience tasks in conditions of increasing difficulty. The study involved 64 dogs, classified as expert (completed an obedience course of 6 months, N = 20), intermediate (in training, N = 21) and novice (no training received, N = 23). In the experiment, the handler had to make the dog perform a sequence of three exercises. As first exercise (stay), handlers had to obtain a waiting posture by the dog, step back by 2.5 m and wait 30 s. The following two exercises were identical to the stay, but respectively a bowl with some food (food) and a toy (toy), were placed close to the dog before asking the desired waiting posture. The average duration of gazes (GL) and the frequency of gaze shifts towards the handler (GF) were collected in the two minutes preceding the exercises (baseline attention) and while the dogs were performing the requested exercises. In baseline GL was affected by the dog’s sex (F2,57 = 4.98, P = 0.011, GLM anova), being highest in intact females, and training level (F2,57 = 5.27, P = 0.008) being highest in expert dogs. During obedience exercises GL was affected by the exercise (F2,158 = 11.57, P < 0.001) being highest in stay, and by the training level (F2,158 = 25.02, P < 0.001), being highest in expert and lowest in novice dogs. The frequency of gaze shifting was affected by an exercise*sex interaction (F2,154 = 2.48, P = 0.046), with intact females showing higher GF in toy than all other exercise*sex combination. Moreover, GF was affected by the dog’s training level (F2,154 = 6.64, P = 0.002), being highest in novice dogs. Different mechanisms could contribute to explain our results, including direct effects of training on interspecific attention patterns as well as indirect effects of the dog-owner relationship. The role and weight of such mechanisms in shaping dogs’ attention to owners’ remains to be addressed.
Contents
Surgical sterilization of dogs and cats is a well‐accepted measure for population control in some countries, but is considered unethical as an elective surgery in other countries. This is a review of what is known regarding positive and negative effects of gonadectomy surgery on individual animals and on societal management of unowned dog and cat populations.
While some research has indicated that ovarian hormone therapy (HT) benefits memory and decreases risk of Alzheimer's disease in menopausal women, several newer studies have shown null or detrimental effects. Despite the null and negative cognitive findings, the numerous studies showing positive effects beg the question of what factors determine whether HT acts as a neuroprotectant or a risk factor for brain functioning. Using middle-aged female rats, we directly compared six HTs. We evaluated the effects of ovariectomy, tonic low-dose, tonic high-dose and biweekly cyclic estradiol treatment, as well as whether progesterone altered the effectiveness of any one of these oestrogen regimens. Animals were tested on spatial and complex cued (intramaze patterns) reference memory using variants of the Morris maze. The tonic low-dose and cyclic estradiol treatments improved spatial performance, while the addition of progesterone reversed these beneficial cognitive effects of estradiol. Additionally, all groups learned to locate the platform on the cued task; however, an egocentric circling strategy was used with sham ovary-intact and hormone-replacement groups showing the most efficient search strategy. Although the question of memory retention 8 weeks after the first cognitive assessment was addressed, a large number of animals died between the first and second test, rendering the retest uninterpretable for many group comparisons. Specifically, both doses of tonic estradiol dramatically increased the number of deaths during the 17-week experiment, while the cyclic estradiol treatment did not. Progesterone decreased the number of deaths due to tonic estradiol treatment. Our findings suggest that the dose of estradiol replacement as well as the presence of progesterone influences the cognitive outcome of estradiol treatment. Further, there appears to be a dissociation between HT effects on cognition and mortality rates.