Monday, September 22, 2014

Optimism Index in Dogs


Photo Credit: © B.Stefanov / Fotolia
Dogs generally seem to be cheerful, happy-go-lucky characters, so you might expect that most would have an optimistic outlook on life.

In fact some dogs are distinctly more pessimistic than others, research from the University of Sydney shows.

"This research is exciting because it measures positive and negative emotional states in dogs objectively and non-invasively. It offers researchers and dog owners an insight into the outlook of dogs and how that changes," said Dr Melissa Starling, from the Faculty of Veterinary Science. Her PhD research findings are published in PLOS One today.

"Finding out as accurately as possible whether a particular dog is optimistic or pessimistic is particularly helpful in the context of working and service dogs and has important implications for animal welfare."

Dogs were taught to associate two different sounds (two octaves apart) with whether they would get the preferred reward of milk or instead get the same amount of water. Once the dogs have learnt the discrimination task, they are presented with 'ambiguous' tones.

If dogs respond after ambiguous tones, it shows that they expect good things will happen to them, and they are called optimistic. They can show how optimistic they are by which tones they respond to. A very optimistic dog may even respond to tones that sound more like those played before water is offered.

"Of the dogs we tested we found more were optimistic than pessimistic but it is too early to say if that is true of the general dog population," said Dr Starling.

However it does mean that both individuals and institutions (kennels, dog minders) can have a much more accurate insight into the emotional make-up of their dogs.

According to the research a dog with an optimistic personality expects more good things to happen, and less bad things. She will take risks and gain access to rewards. She is a dog that picks herself up when things don't go her way, and tries again. Minor setbacks don't bother her.

If your dog has a pessimistic personality, he expects less good things to happen and more bad things. This may make him cautious and risk averse. He may readily give up when things don't go his way, because minor setbacks distress him. He may not be unhappy per se, but he is likely to be most content with the status quo and need some encouragement to try new things.

"Pessimistic dogs appeared to be much more stressed by failing a task than optimistic dogs. They would whine and pace and avoid repeating the task while the optimistic dogs would appear unfazed and continue," said Dr Starling.

"This research could help working dog trainers select dogs best suited to working roles. If we knew how optimistic or pessimistic the best candidates for a working role are, we could test dogs' optimism early and identify good candidates for training for that role. A pessimistic dog that avoids risks would be better as a guide dog while an optimistic, persistent dog would be more suited to detecting drugs or explosives."

Dr Starling has been working with Assistance Dogs Australia, a charity organisation that provides service and companion dogs to people with disabilities, to investigate whether an optimism measure could aid in selecting suitable candidates for training.

The research not only suggests how personality may affect the way dogs see the world and how they behave but how positive or negative their current mood is.

"This research has the potential to completely remodel how animal welfare is assessed. If we know how optimistic or pessimistic an animal usually is, it's possible to track changes in that optimism that will indicate when it is in a more positive or negative emotional state than usual," said Dr Starling.
"The remarkable power of this is the opportunity to essentially ask a dog 'How are you feeling?' and get an answer. It could be used to monitor their welfare in any environment, to assess how effective enrichment activities might be in

Citation
Starling MJ,  Branson N, Cody D, Starling TR, McGreevy PD. 2014. Canine Sense and Sensibility: Tipping Points and Response Latency Variability as an Optimism Index in a Canine Judgement Bias Assessment. PLoS ONE, 2014; 9 (9): e107794 DOI: 10.1371/journal.pone.0107794

Friday, September 12, 2014

Dogs are the dominat prey of Indian Leopards

Photo credit: WCS India
A new study led by the Wildlife Conservation Society reveals that in India's human dominated agricultural landscapes, where leopards prowl at night, it's not livestock that's primarily on the menu -- it is man's best friend.

The study, which looked at scat samples for leopards in India's Ahmednagar's district in Maharashtra, found that 87 percent of their diet was made up of domestic animals. Domestic dog dominated as the most common prey item at 39 percent and domestic cats were second at 15 percent.

Seventeen percent of the leopard's diet consisted of assorted wild animals including rodents, monkeys, and mongoose, and birds.

Livestock, despite being more abundant, made up a relatively small portion of the leopard's diet. Domestic goats, for example, are seven times more common than dogs in this landscape, yet only make up 11 percent of leopard's prey. The author's say this is because goats are less accessible and often brought into pens at night, while dogs are largely allowed to wander freely. Cows, sheep, and pigs were also eaten, but collectively made up less than 20 percent of leopard's food. Most domestic cattle in this region are too large to be preyed on by leopards.

The authors of the study say that the selection of domestic dogs as prey means that the economic impact of predation by leopards on valuable livestock is lower than expected. Thus, human-leopard "conflict" is more likely to be related to people's fears of leopards foraging in the proximity of their houses and the sentimental value of dogs as pets.

Study co-author Ullas Karanth, WCS Director for Science-Asia, said: "During the past two-to-three decades, legal regulation of leopard hunting, increased conservation awareness, and the rising numbers of feral dogs as prey have all led to an increase in leopard numbers outside of nature reserves in agricultural landscapes. While this is good news for conservation and a tribute to the social tolerance of Indian people, it also poses major challenges of managing conflict that occasionally breaks out. Only sound science can help us face this challenge."

Citation

Vidya Athreya, Morten Odden, John D. C. Linnell, Jagdish Krishnaswamy, K. Ullas Karanth. A cat among the dogs: leopard Panthera pardus diet in a human-dominated landscape in western Maharashtra, India. Oryx, 2014; 1 DOI: 10.1017/S0030605314000106

Tuesday, September 9, 2014

Dogs in the prehistory of Western Europe based on archaeozoological evidence

The representations of prehistoric dogs are very rare.
 In this example from the Neolithic site of Catal Hüyük
 in the Near Orient (7000 BC), a dog seems to be 
assisting the hunt (from Benecke N. 1994, Der Mensch 
und seine Haustiere. Die Geschichte einer 
jahrtausendalten Beziehung. Thesis).
In a new paper, Horard-Herbin, Tresset, and Vigne examine the history of the dog in Western Europe through archaeozoology evidence, and make inferences about the relationships between humans and dogs through prehistory. The dog was domesticated by Upper Paleolithic hunter-gatherers, but the domestication process remains unclear, in terms of chronology, geographic origin, and recurrence of the phenomenon. What follows is my summary of the paper, representing the author’s view on the history of dogs in Europe. The entire paper is available on-line.
The first dogs appeared in the Late Glacial between 18,000 and 10,000 BC, from the Magdalenian period to the end of the Epipalaeolithic. Evidence for morphologically transformed animals come from the Iberian Peninsula, Siberia, Aquitaine in France, the French Alps, central and northern Europe, and the Near East. In the authors’ view multiple independent domestication events took place across much of the Old World. Recent morphometric analyses of dogs from the southeast and north of France have revealed marked morphological differences between a group of small-sized dogs originating in the West and other much larger dogs with a different physical structure from northeast Europe in the same period; indeed, some of these “larger dogs” were probably wolves. This study led to formally identifying two very distinct populations of dogs during the Upper Paleolithic, which potentially reflect distinct centers of domestication. These findings support the fragmentation in the landscape in the Late Glacial of Eurasia due to the polar and orogenic ice caps, and also the diversity and relative isolation of hunter-gather cultures from the same period. This is also in line with the common practice in hunter-gatherer societies of pet keeping, where young animals were integrated in the family group and breast fed with the children to compensate for the animals taken from nature through hunting. This practice, demonstrating that hunter-gatherers were as capable of raising animals as the Neolithic age people, could have played an important role in the domestication of dogs in different places.
 Late Glacial dogs displayed a wide variety of statures, from medium-sized Natoufian dogs in the Near East and their Northern Zagos contemporaries (height: 45 to 60 cm), to medium or large sizes (height > 60 cm) for dogs in eastern Europe, to very small dogs (height 30 to 45 cm or < 30 cm) in Germany, Switzerland, the east of France, and the southwest and north of Spain. Other large canid fossils dated about 30,000 BC found in Belgium, Siberia (27,000 BC), and the Czech Republic (24,000 BC) have been interpreted as domestic dogs 15,000 years before the others. However, analyses suggest that the morphological character considered by the authors of these discoveries as identifying domestication are instead morphological variations of the Upper Paleolithic wolves, whose morphological variability remains poorly known.
Dogs were scarce in the early Neolithic of Europe, with the notable exception of the Herxheim pit enclosure (western Germany, Linearbandkeramik culture, end of the sixth millennium cal. BP), where dogs were found in partial association with human remains. The few data collected for this period suggest the animals remained relatively large, though significantly smaller than the wolf. Modifications such as shortening of the face and dental crowding were also already obvious in animals of this period. Tooth anomalies (essentially missing teeth) were frequent. The decrease in size was accentuated until the fourth millennium cal. BP and culminated in the Neolithic/Chalcolithic period with the occurrence of small and very small dogs in southeastern Europe but also in western Europe (at Bercy and many other sites of the Chasséen complex and related cultures). These small dogs are rarely found complete and are often retrieved from rubbish pits and dumping areas, which strongly suggests that they were commonly consumed, even when cut or burn marks are absent. Estimation of age based on tooth eruption and tooth wear shows that young and subadult animals were the most abundant, strengthening the hypothesis that dogs were consumed in this period.
Few dogs found at the end of the Neolithic in Western Europe were larger than those evidenced for the fourth millennium. The incomplete dogs found in a mass grave at Bury in northern France were large individuals with slightly shortened faces. Analyses of their DNA showed that one of them at least was black, whereas another still retained the wild coat color. Overall, data from the Mesolithic and Neolithic periods in Europe provide evidence about the evolution of dog phenotypes and the status of dogs.
Bronze Age dogs are rare, but those studied from central and Eastern Europe, the British Isles, and the Italian and Iberian peninsulas are generally of a homogeneous size. 40 to 50 cm with occasionally a few larger individuals, but never smaller specimens. The only region for which this is not true is Switzerland where the size of dogs also increased significantly from the late Neolithic, but where in the late Bronze Age, a population of larger, sturdier dogs remained (50 to 60 cm).
During the Iron Age, the majority of the canine population remained morphologically homogeneous, with dogs averaging 40 to 55 cm in the British Isles, Gaul, central Europe, and Italy. They were slender animals whose leg bones presented no particular modifications, such as twisting or marked sturdiness, which characterized certain morphotypes from the Roman period. Nevertheless, at the end of the Gallic period, an increase in size at the withers could be observed with the appearance of small and large dogs. Taking the example of Gaul, the first phenomenon during the second century BP was the appearance of small dogs in certain habitats only, namely those of aristocrats, and in certain sanctuaries. These small individuals were isolated and always associated with a medium-sized population from which they seemed not to have originated. According to the current state of knowledge, only three sites of Celtic Europe show a bipartite distribution of wither heights, a large number of individuals, and all the intermediate sizes: Levroux (Indre, France) and Manching and Berching-Pollanten, both in the same region of Bavaria. On the site of Levroux, some skulls show a marked shortening of the face associated with dental pathologies. Indeed, some teeth are missing or overlapping, which is firm evidence of face shortening, but there is no sign of limb bone modification. The highlighting of these specific breeding places is an interesting observation in regards to the ancient authors who indicated that specialized dog breeding existed in Gaul and Great Britain, mainly for hunting or war dogs.
At the end of La Tène period on a few European Celtic sites, very small dogs appeared that qualify as dwarfs. They were extremely rare, isolated among populations from which they could not have stemmed, and their sizes being outside all the size ranges known in the Iron Age. This is the case for the only complete skeleton of a dog measuring 27 cm at the withers from the Oppidum of Rheinau, Switzerland, and whose presence has been interpreted as an import of a pet from the Mediterranean region. This hypothesis is in line with those developed by several authors suggesting that these dwarf lapdogs, much appreciated by Roman ladies, originated in the Roman Empire. They would have been offered to the upper classes of the Celtic society by the Romans, in the same way as observed for horses, and attested to by certain ancient authors. Included with luxurious gifts, they would have had an exceptional value and status.
The limitation of this import hypothesis is that on examining the range of wither heights of dogs in Italy from the Neolithic to the end of the Roman period or dogs from Pompeii, no dwarf dogs less than 29 cm can be observed during what is known as the Early Roman period (third century BC to second AD corresponding to our chronology of the Iron Age and the Early Roman period), and those smaller than 25 cm only appeared at the end of the Roman Empire (third to sixth century AD;). On the other hand, dwarf dogs (20, 22, and 23 cm) have been found in Germany, Hungary, France, and Great Britain from early Roman times. For the latter, observed that these dogs were smaller than their contemporaries in Italy. This is clear evidence that the hypothesis of dwarf Roman dogs being imported is not pertinent for the Iron Age, and the function, origin, and means of circulation of dwarf dogs at the Celtic European scale remain unknown.
During the second Iron Age, large dogs reaching a maximum wither height of 65 cm were found in Europe, corresponding approximately to the size of a Gordon Setter, but which had still not reached the 75 cm height of a very large dog (taller than a wolf), which did not appear until the Roman period. These large dogs were found in Belgium and Germany and very rarely in Gallic settlements with less than 10 individuals measuring more than 60 cm. It is difficult to determine whether these dogs represent the upper limit of the size range of middle-sized populations, stemmed from slightly larger populations persisting in certain regions (in Austria, on the Durezza cave site, the size range of dogs from the first Iron Age was from 49 to 64 cm; n = 126), or were the result of specific breeding that has not been identified through archaeology yet, such as war dogs mentioned by ancient authors. In general, studies investigate samples that are too small to enable definition of a population, and only with the development of genetic studies will light be shed on this question.
In any case, the very small and very large individuals are extremely rare, and it is complex to determine whether their morphotypes, identified as specific through our archeozoological analyses, are in fact linked to a specific status. It has been established that some individuals were incinerated with their “master” in a funeral context, while others were simply eaten, and the fate of some of them did not differ fundamentally from that of medium-sized dogs, as explained below.
The Celts lived with a pack of dogs of similar morphology. However, from the skeletal evidence available, it is clear this was the beginning of selection of certain morphotypes, as illustrated by the shortening of the face of certain skulls and the associated pathologies, and the diversification of wither height. This is reflected in the 30 or so “races” of dogs cited by ancient authors and for which iconographic representations have remained. In the texts, they are characterized by their geographic origins and by the services they provided: pet, hunting dog, war or guard dog, some coming from Gaul such as the Vertagus or the Ségusien hound.
The authors conclude that a general and partial approach to the evolution of dogs in Europe from the Paleolithic to the Iron Age shows to what extent certain questions regarding this species reoccur across time. In particular, at the beginning of the Neolithic and at the end of the Iron Age, indigenous lines and exogenous inputs can be observed. It would be interesting to characterize these new dogs from the point of view of their bone morphology (e.g., size, robustness, and proportions) and their genetic characteristics (e.g., origins and coat color) to measure their impact on the population in place over the long term (e.g., cohabitation, replacement). These elements are also necessary to draw a link between specific morphotypes and functions as certain modern-day societies (e.g., South Korea) have races of dogs for meat production, even though the term race is completely inappropriate for the periods of interest. (The term race refers to a population of the same species having distinct hereditary, morphological, and physiological characteristics according to the standards defined in the herd and flock books drawn up since the 19th century. For all earlier periods, the more appropriate term morphotype should be used.)

Citation
Horard-Herbin M-P. Tresset A, Vigne D-D. 2014. Domestication and uses of the dog in western Europe from the Paleolithic to the Iron Age. Animal Frontiers 4 (3): 23-31.