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Summary Companion Animals
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The document is a summary of the theory discussed during lectures, suggested articles and suggested reading material of the course Companion Animals.
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COMPANION ANIMALSLECTURE 1 – INTRODUCTION AND DOMESTICATION
Why do we keep pets?
- Some might say we shouldn’t keep them because of risk of zoonoses, injuries, it is a risk for the
environment from an ecological perspective (e.g. they can hunt) and they need a lot of resources
e.g. feed that has to be transported
- Positive aspects of keeping pets:
o They are sources of information for safety and danger, e.g. they can sense tsunami
o They give us companionship and help us build social relationships
o They make us more active and give us motive to go outside
Important to understand their needs to ensure their welfare, e.g. what are their behavioral needs (rabbits
should not stay alone), take care of health problems (e.g. some dog breeds are bred to have a small head
but they often have a headache), be careful of their digestive physiology (e.g. diet rich in starch for cats is
not really digestible).
What is a companion animal/pet?
Companion animal:
- A pet or other domestic animal
- An animal that someone keeps for company and enjoyment
Pet:
- A domestic or tamed animal kept for companionship or pleasure, treated with care and affection
- An animal kept for amusement or companionship
- A pet (or companion animal) is an animal kept primarily for a person’s company or protection
- E.g. a capybara is not really a pet because it is not domestic or tamed
NB: what is considered a companion animal depends on the context:
- There may be differences between cultures and different times/eras, e.g. in some cultures, sloths
are kept as pets
- Depending on the context, certain animals are considered companion animals or production
animals (e.g. horses can also be used for meat)
When did we start keeping companion animals?
- There is historical evidence that dogs were kept by humans thousands of years ago, e.g. to help
with hunting or as guard dogs
- Domestication of animals started in the Neolithic era, when people started settling in villages and
cultivating crops
- Domestication = consists in taking an animal from its natural environment and putting it into a new
domestic environment
- NB: not all animals are suitable for domestication characteristics that make animals suitable for
domestication are e.g. non-aggressive, easy to control, animals that live in large groups, animals
that are herbivores or omnivores, animals with tolerance of different environments and
environmental changes
o Animals not suitable are solitary animals, carnivores or with very specific diets, aggressive
and that avoid contact with people, sensitive to environmental change and that tolerate
few environmental conditions.
What determines if an animal species adapts well to captivity?
- Boldness (bold vs. timid/fearful) timid species take flight more readily and show greater stress if
they cannot escape
, - Flexibility (generalist vs. specialist) specialists have difficulty to cope with new environments
and food supply, because they need specific conditions and feed
- Ranging (resident vs. migratory) migratory species have more difficulties at being domesticated;
when their environment changes, they prefer to leave rather than adapting their behavior
Pathways of domestication
Commensal pathway:
- First there is habituation of the animal to be
close to humans and in a new environment,
- Second, there is partnership so human-animal
interactions might bring some benefit, e.g.
dogs helped with hunting
- Third, directed breeding; it means humans
choose which animals to breed for
reproduction and select specific desirable
traits
- This pathway was used with dogs
Prey pathway:
- First, the animal is prey e.g. herbivores kept for milk
- Then humans started managing these animals
- And directed breeding by human occurs, so humans decide how animals will breed and which traits
are important
Directed pathway:
- The animal is a prey, which then is subjected to human control and directed breeding
Domestication definition process by which a population of animals becomes adapted to man and to the
captive environment by some combination of genetic changes occurring over generations and
environmentally induced developmental events recurring during each generation
Domesticated animals have four main characteristics :
- Their breeding is controlled by humans
- They provide a product or service useful to people (e.g. food, guarding, hunting, companion)
- They are tamed
- They have been selected away from the wild type
NB: pet animals are not necessarily completely domesticated, e.g. cats are not fully domesticated because
they often choose their partner for breeding, they can find food on their own
Domestic animals show some common morphological and physiological changes compared to wild
animals:
- They can develop different coat colors and patters, e.g. white spots on the head
- Floppy ears
- Shorter legs, shorter and curly tails and shorter nose
- Wider skulls
- Changes in gene expression
- Lower stress levels in the animals
- Loss of species-specific, wild-type behavior response to humans (e.g. no aggression or fear)
- Ability to breed in any season and often more than once a year
Article – Evolutionary view of domestication
Most domestic species evolved by artificial selection. Domesticate animals have these characteristics:
- Are tolerant to people, or they don’t have fear of them
, - Domestic animals are in principle mated by humans (so they don’t choose their partner)
- Reproductive cycles and diets are changed
- Have common physical and physiological adaptations, e.g. dwarfs and giants, piebald coat color,
wavy/curly hair, shorter and curled tails, floppy ears.
- Their behavior is changed, in ways that affect mood, emotion, social communication.
NB: domestication is different from taming —>
- Domestication = permanent genetic modification that leads to predisposition toward humans
- Taming = conditioned behavioral modification of an individual.
- Not all tamed animals are necessarily domesticated (e.g. wild animals in zoos are tamed but not
domesticated), and vice versa.
Domestication of animals ranges from 15000 BP (dog) to 8000 BP (cattle). Domestication started when
hunter-gatherers became sedentary and started agriculture.
Most domesticate animals were behaviorally preadapted, because they had characteristics favorable for
domestication —> they lived in large groups, were omnivores or herbivores, non-aggressive, easy to
control, tolerate different environments, and able to reproduce normally in presence of people.
Unfavorable characteristics for domestication are being territorial, solitary, carnivores or dietary
specialists, aggressive, difficult to control, tolerate few environments.
Domestication of dogs —> dogs are the earliest domesticates. Dogs originate from wolves. It is believed
that a group of wolves started getting close to humans to steal preys, and then were used as barking
sentinels. They started differentiating from wild wolves and became proto-dogs, that became more tolerant
to humans. People also started controlling their mating —> dogs are result of artificial selection.
Domestication of cats —> cats derive from African wildcats, however if we look at the favorable
characteristics for domestication, wildcats are not good candidates —> they are carnivores, solitary and
territorial, and don’t have a utility like dogs and farm animals. It is believed that wildcats started exploiting
human environments e.g. by eating mice in villages, and humans tolerated their presence. So, cat is a
product of natural selection.
NB: cat domestication is not considered complete because —> most cats still choose their partner, most
feral cats obtain food on their own, and domestic cats remained very similar morphologically to wildcats.
Article – species differences in responses to captivity
Animals respond differently to captivity —> they are usually healthier, live longer and breed more
successfully than conspecifics living in the wild. However, some captive animals do not respond so well and
have lower survival and welfare. e.g. elephants in zoos have reproductive problems like high infant
mortality, and perform stereotypic behavior.
Species that are closely related can show very different responses to captivity —> this can be verified with
comparative methods, i.e. comparing data from different species. This method can also be used to
investigate welfare problems. e.g. a study compared the responses of different primate species to presence
of zoo visitors —> they found that human presence increased activity in the animals, in particular small
primates were more threatened by human presence.
Studies on lab animals suggest that animals that thrive in captivity also tend to be invasive (‘weed’
species) and tolerate urbanization —> it was shown that when species that lived close to humans are
introduced in a new environment, they are more successful at surviving and spreading . Therefore, a new
hypothesis is that invasive species are predisposed to good welfare in captivity.
Some characteristics of animals can predict invasiveness and tolerance of human environments:
- Boldness —> bold species have little fear when encountering threats. E.g. Magellanic penguins
have little fear of humans, so they still reproduce well in ecotourist sites, while more fearful
penguin species do not reproduce well. The trait of boldness vs. fearfulness could explain why zoo
life is more stressful for some species but not others.
- Resident vs. migratory lifestyle —> non-migratory (resident) species tend to invade environments
more successfully. E.g. non-migratory parrot species have more success when establishing in new
locations than migratory species. In captivity, being migratory could predict poorer welfare.
- Behavioral flexibility —> it is the ability to cope with new stimuli or resources. Animal generalists
that live in different habitats and eat different foods (are not specialized) are more invasive and
, establish in new environments more successfully. In captivity, behavioral INflexibility can
compromise the ability to habituate to human proximity, to new types of shelter or foraging
modes.
Are vulnerable wild specie also vulnerable in captivity? —> it seems that common species can thrive in
captivity, but at-risk species are prone to poor welfare. E.g. among captive canids, vulnerable species have
lower pup survival, and endangered birds are harder to breed in captivity.
Article – animal evolution during domestication (domesticated fox example)
Hypothesis —> domestication might involve changes in the activity of genes that regulate development,
in particular the genes that control behavior. Experiment with silver foxes to test this hypothesis:
Silver foxes raised in fur-farms were selected for reproduction —> NB: these foxes were not
domesticated yet, and still had their wild characteristics (fear of humans, normal morphology and
reproductive behavior). Therefore, the foxes were selected for tameability (addomesticabilità).
At every generation, pups were subjected to human handling —>The foxes that still showed aggressive
or avoidance behavior were removed from selection.
This selection resulted in:
- Behavioral changes —> at every generation, more pups showed dog-like behavior (e.g. tail
wagging, and searched for human contact). Normally, pups of wild animals are more explorative
until a certain age when they start developing fear for humans. In the tamed foxes, the fear
response to humans was slowed down and appeared later.
- Physiological changes —> the seasonal reproductive pattern changed: they were able to mate
outside of the usual reproductive season, and sexual maturity was reached earlier.
- Morphological changes —> color pattern, floppy ears, curly tails, shorter legs, nose and wider skull.
- Neuroendocrine changes —> the genes that control development might also control
glucocorticoids. When wild pups start developing fear and reduce exploratory behavior at a certain
age, their cortisol levels (stress hormone) increased. In the tamed pups, this increase occurred
later. In addition, domesticated foxes also had higher levels of serotonin, which probably
decreased the aggressive behaviors towards humans.
LECTURE 2 – HUMAN-ANIMAL RELATIONSHIPS (focus on dogs)
Animal welfare criteria:
- Good feeding (no hunger and thirst)
- Good housing (thermal comfort, ease of movement)
- Good health (no injuries, no disease, pain)
- Appropriate behavior (expression of social behavior, good human-animal relationship, positive
emotional state)
Key factor of early domestication (refers to article on foxes above):
- Early 1960s foxes with low defensive reactions to humans were selected as parents of the first
generation (Russian scientist Belyaev) the aim was to select foxes for tameness
- Following generations were subjected to more intensive contact with humans foxes that
retained aggressive or fearful reactions were eliminated from the selection program
- In generation 4 of selection, there were the first pups without aggressive-fearful reactions to
humans
- In generation 6, there were the first “elite pups” elite means they are very social, friendly with
humans
o The number of these elite foxes increase fast over generations only 4 in generation 6,
but 642 in generation 42
Markers of domestication = characteristics that domesticated animals typically develop:
- Different coat colors and patterns, e.g. white star on the head it happens because hormones
involved with lower stress and positive emotions also influence coat color
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