Captive environments like zoo exhibits offer limited space, lacking many of the environmental stimuli that are present in the wild. This may reduce animal welfare and potentially lead to the development of stereotypic behaviour like pacing. Environmental enrichment is used to prevent and reduce pacing and enhance animal well-being. The aim of this project was to evaluate sensory enrichments, and the effect of such enrichment on pacing in a group of Northern lynx by means of new, automated monitoring technologies in combination with traditional visual observations. The lynxes were exposed to valerian, catnip and cinnamon as olfactory enrichment. The acoustic enrichments were play-backed mouse squeals, roe deer barking and lynx vocalizations, and live crickets. The responses of the lynx were recorded by logging their subcutaneous HDX pit tags, and Bluetooth Low Energy (BLE) tags mounted on collars and using a wildlife camera. The results showed that catnip elicited clear “catnip responses” i.e sniffing, rubbing, biting and licking. The sounds were found to attract the lynxes and increase their arousal. One of the sounds, the lynx calls, elicited social behaviour. However, none of the sensory treatments reduced pacing. The combination of these automated technologies with visual observation was powerful to evaluate the effect of enrichment on captive lynxes and to monitor their activity patterns and stereotypic behaviours. Sensory enrichment could also be used in the wild as lures to attract lynxes to BLE or HDX PIT tag logging stations and to wildlife cameras, as part of monitoring a lynx population.

<p> The underlying goal of this dissertation is to understand how the amygdala, a brain region involved in establishing the emotional significance of sensory input, contributes to the processing of complex sounds. The general hypothesis is that communication calls of big brown bats (<i>Eptesicus fuscus</i>) transmit relevant information about social context that is reflected in the activity of amygdalar neurons. </p><p> The first specific aim analyzed social vocalizations emitted under a variety of behavioral contexts, and related vocalizations to an objective measure of internal physiological state by monitoring the heart rate of vocalizing bats. These experiments revealed a complex acoustic communication system among big brown bats in which acoustic cues and call structure signal the emotional state of a sender. </p><p> The second specific aim characterized the responsiveness of single neurons in the basolateral amygdala to a range of social syllables. Neurons typically respond to the majority of tested syllables, but effectively discriminate among vocalizations by varying the response duration. This novel coding strategy underscores the importance of persistent firing in the general functioning of the amygdala. </p><p> The third specific aim examined the influence of acoustic context by characterizing both the behavioral and neurophysiological responses to natural vocal sequences. Vocal sequences differentially modify the internal affective state of a listening bat, with lower aggression vocalizations evoking the greatest change in heart rate. Amygdalar neurons employ two different coding strategies: low background neurons respond selectively to very few stimuli, whereas high background neurons respond broadly to stimuli but demonstrate variation in response magnitude and timing. Neurons appear to discriminate the valence of stimuli, with aggression sequences evoking robust population-level responses across all sound levels. Further, vocal sequences show improved discrimination among stimuli compared to isolated syllables, and this improved discrimination is expressed in part by the timing of action potentials. </p><p> Taken together, these data support the hypothesis that big brown bat social vocalizations transmit relevant information about the social context that is encoded within the discharge pattern of amygdalar neurons ultimately responsible for coordinating appropriate social behaviors. I further propose that vocalization-evoked amygdalar activity will have significant impact on subsequent sensory processing and plasticity.</p>

Dogs are well adapted to a life close to humans and are capable of understanding several human social cues. Turn-taking is a fundamental phenomenon in human conversations, yet no research of turn-taking in interspecies vocal communication has been done. This pilot study therefore aimed to develop a test method in order to analyze if turn-taking occurs in interspecies vocal communication between dogs and humans and if turn-taking can be correlated with specific behaviors in dogs. By analyzing a vocal conversation between seven dogs and their owners during a request situation in their home environment, this study found support for turn-taking existence in dog-human vocal communications. In general, owner-dog vocal communication could be linked to positive events, such as tail wagging and eye contact. Meanwhile, a lower frequency of vocal turn- taking could be linked to stress related behaviors, such as lip licking. Owner in dyads where more vocal overlap occurred tended to score the owner-dog relationship and communication abilities with lower grades, suggesting the absence of turn-taking was experienced as unpleasant for the owner as well. In conclusion, findings from current study highlight the unique coevolution of dogs and humans and opens up for future research of turn-taking in interspecies vocal communication.

Separation anxiety is one of the most common behavioral disorder in companion dogs. Dogs not suffering from separation anxiety may still exhibit separation-related behaviors, which can differ depending on environmental contexts. In the present study, dogs without separation-related problems were video recorded during a short separation (3 min) from, and during reunion with, their owner. Comparison was done between if the dogs had played or been calm pre-separation. The dogs spent most time in proximity to the entrance and gazing towards where the owner left during separation. Their body-position was mostly standing, followed by sitting. All dogs were wining during separation, which occurred approximately four times more than barking. Dogs that had played pre-separation were running around more and had a longer latency to the first movement, compared to when they had been calm pre-separation. During reunion, when dogs had played pre-separation, they wagged their tail more and had a longer latency to lip licking, compared to when they had been calm pre-separation. The separation behaviors that occurred in this study aligns with previous work in this subject. Furthermore, one can suggest that play pre-separation might have an effect on separation behaviors, where speculations can be done if the positive affect associated with play might be the underlying cause for these findings.

The aim of this study was to investigate if the dog’s behaviour and the interactions between the dog and the owner   differ depending on lifestyle, breed or sex of the dog. For this we employed the Strange Situation Procedure, a test inspired from Mary Ainsworth´s study,   which investigated the attachment of human infants to their mothers. There were two breeds, Border collie and Shetland sheepdog and a total of 58 dogs that participated in this study. The two breeds were divided into two lifestyles, competition dogs and pet dogs. A PCA was used to find correlations between the behavioural variables and the factors were then analysed in a Mann Whitney U test to test the differences between breed, sex and lifestyle. In this study no differences in behaviour between the two lifestyles were shown. However, the results showed that there were some differences between the two breeds and between the two sexes in behavioural expressions. The differences between the breeds were quite expected because there are many different breeds today which are selected for various morphology and behavioural traits which could influence their behaviour. The difference in behaviour between the two sexes can be because of evolutionary heredity. Further studies on this subject should have bigger and more even sample size, longer separation time, a more balanced gender distribution of the owners and to also analyze the cortisol levels.

Cooperative behaviours among individuals play a crucial role in social interactions. There is a special interest in investigating the occurrence of cooperation among apes, because this knowledge could as well shed light on evolutionary processes and help understand the origin and development of cooperation in humans and primates in general. Gibbons are phylogenetically intermediate between the great apes and monkeys, and therefore represent a unique opportunity for comparisons. The aim of the present study was to discover whether or not gibbons (Hylobates lar) show cooperative behaviours among each other. In order to test for the respective behaviours, the gibbons were presented with a commonly used experimental cooperative problem-solving task. Additionally, social behaviours were recorded during behavioural observations. The gibbons in this study did not exhibit cooperative behaviours during the problemsolving task. Behavioural observations revealed that the gibbons spent significantly more time ‘out of arm’s reach to everyone’, suggesting that they are less involved in social interactions than other, more cooperative apes. Both findings combined support the “social brain hypothesis”, which predicts that cognitive abilities are constrained by the complexity of the animals’ social life. Based on previous findings of occurrences of cooperative behaviours in two other primate lineages (i.e. New World monkeys and Old World monkeys) it was suggested that cooperation in primates was a matter of a convergent evolutionary processes rather than a homologous trait.

Meerkats are known to strongly rely on chemical communication in social contexts. However, little is known about their use of the sense of smell in food detection and selection. The aim of the present study was therefore to assess whether meerkats are able to (1) detect hidden food using olfactory cues, (2) distinguish the odour of real food from a single food odour component, and (3) build an association between the odour of real food and a novel odour. I employed the buried food test, widely used with rodents to assess basic olfactory abilities, designed to take advantage of the propensity of meerkats to dig. I found that the meerkats were clearly able to find all four food types tested (mouse, chicken, mealworm, banana) using olfactory cues alone and that they successfully discriminated between the odour of real food and a food odour component. In both tasks, the animals dug in the food-bearing corner of the test arena as the first one significantly more often than in the other three corners, suggesting development of an efficient foraging strategy. No significant association-building between a food odour and a novel odour was found within the 60 trials performed per animal. I conclude that meerkats are able to use olfactory cues when foraging and that their sense of smell is well-adapted for recognizing specific odours of behavioural relevance. To the best of my knowledge, this is the first study to successfully employ the buried food test with a carnivore species.

Comparative studies of taste perception have found that primates may differ markedly in their sensitivity for substances perceived as sweet by humans. These findings raise questions about the reason that may underlie these differences in sweet-taste sensitivity between species. The aim of the present study was to assess the taste responsiveness of chimpanzees (Pan troglodytes verus) to seven substances tasting sweet to humans and to compare the results with those of other primate species. Using a two-bottle preference test (1 min) I found that the taste preference thresholds of the chimpanzees for five food-associated carbohydrates ranged between 20-30 mM for sucrose, 20-50 mM for fructose, 60-80 mM for glucose, 50-80 mM for maltose, and 30-80 mM for lactose. Taste preference thresholds for two steviol glycosides ranged from 0.04-0.05 mM for stevioside, and 0.03-0.05 mM for rebaudioside A. The chimpanzees displayed clear preferences for all sweet-tasting substances presented. In line with data obtained in other primates, the taste preference threshold of the chimpanzees for sucrose was lower compared to the other carbohydrates presented and the taste preference thresholds for stevioside and rebaudioside A were lower compared to sucrose. In general, the taste sensitivity of the chimpanzees fell into the range of data reported in other nonhuman primate species. Interestingly, the taste preference thresholds of the chimpanzees reported here are similar to the taste detection thresholds obtained in humans, despite the fact that the former are only a conservative approximation of an animal’s taste sensitivity. This suggests that chimpanzees may be as sweet-taste sensitive as humans.

Animal personality can be defined as a set of physiological and behavioral characteristics that differ between individuals, but are consistent over time and across situations. The evolution of individual differences in behavior that are consistent over time and situations is still not clear. Our understanding of why animals have personality can be improved by investigating the underlying physiological mechanisms of animal behavior. Serotonin is a key monoamine that serves as a physiological modulator of animal behavior. Selective serotonin reuptake inhibitors are a group of chemicals that increase levels of serotonin in the brain. Fluoxetine is one such chemical and is used to treat depression in humans. In the field cricket (Gryllus bimaculatus), increased levels of serotonin have been linked to higher activity and boldness, which are both personality traits. In the current study, the effects of induced serotonin on activity, exploration, boldness and aggression was investigated. My results show that injecting fluoxetine causes substantial changes in behavioral traits used to describe personality in field crickets. This result is opposite to previous studies, as serotonin induced individuals were less active, less explorative, and won less fights, compared to control individuals. This could be due to serotonin existing naturally within the circulatory system of the field cricket, whereas fluoxetine is a manufactured chemical intended for human receptors, or that fluoxetine has a similar effect in modulating personality in field crickets as in humans. Since fluoxetine acts similarly in field crickets as in humans, an increased understanding of the effects of induced serotonin on different behaviors in field crickets could be beneficial for treating psychological illnesses.

Interindividual differences in animal behaviour that are relatively consistent over time and context are referred to as animal personality. Personality has been recognized throughout the entire animal kingdom, in an array of species like molluscs, arthropods, fish, birds and mammals. The personality of non-human animals has been suggested to vary along five different axes, or continua; boldness-shyness, avoidanceexploration, activity, sociability and aggressiveness. Having a relatively fixed personality may seem nonadaptive compared to infinite behavioural plasticity so the individual would be able to respond adaptively to any changes in the environment. There can be physiological limitations to the phenotypic expressions of any trait, including behaviour. Variation in neuroendocrinology may thus explain why animals have personality. A candidate neurochemical that potentially proximately influences and forms personality, is serotonin (5- HT), one of the most omnipotent neurotransmitter of the animal body. In the many realms of the serotonergic system, there may arise individual differences which forms a proximate basis for differences in personality. In this review paper, I discuss the impact of the serotonergic system on a few different personality traits. Depending on the individual’s motivational state, serotonin can dampen or enhance aggression. Serotonin correlates negatively to anxious traits. Feeding behaviour is affected by serotonin in seemingly opposing directions. Overall, serotonin seem to underlie many behaviours that describe animal personality.