Cause, Function, Evolution and Development of Normal Behaviour Flashcards
Describe domesticated animal behaviour
highly variable amongst orders within classes which reflects differences in ecological niche & domestic selection
all have same functional attributes
mix of single and multifunction
What are the functional attributes of domesticated animal behaviour?
- nutrient capture
- body maintenance
- reproduction
- survival and perpetuation of genes
What are Tinbergen’s 4 Questions?
- Function - why is the animal performing the behaviour / how does it improve fitness
- Evolution - how did it evolve through natural selection?
- Causation - what causes it to be performed / what stimuli/psychological mechanisms cause it?
- Development - how has it developed through the lifetime of the individual, how has it been influenced by learning?
Describe causation of behaviour
- eliciting stimuli
- neural mechanism to produce
e.g., animal aggression
What 3 underlying premises is evolution of behaviour based on?
- Behaviour affects the survival and/or reproduction of the individual
- Behaviour is variable and affected/determined by genes
- Behaviour genes are heritable
What is behaviour subject to and what is it determined by?
subject to natural selection and thus evolution
determined by physical body of the animal
Define embodiment of behaviour
morphological limitations of behaviour
embodiment as anatomy evolves so does behaviour - inextricably linked
What is evolution of behaviour inferred from?
palaeontology (morphological possibilities/limitations) and ecological niche
Define domestication
process by which a population of animals becomes adapted to man and to the captive environment by a combination of genetic changes occurring over generations and environmentally induced developmental events recurring during each generation
What does domestication assume/not assume?
- Does not assume that the genes and the environment operate independently
- Assumes captive environment is different from wild ancestral environment - these differences are consistent over generations - allows evolutionary forces to change gene pool
How can humans accelerate domestication changes in phenotype?
by artificial or gene transfer
Describe the process of loss and/or exaggeration of wild to domesticated traits
- select behaviour traits/lack of traits
- physical traits - embodiment, linked genes/pleiotropy
- changed environment = changed external stimulation of behaviour
- changed environment = changed development of behaviour
What are the pre-adaptations for domestication?
- large gregarious social groups
- non-aggressive
- promiscuous matings
- precocial
- tameable, short flight distance from humans, readily controlled, limited sensitivity to changes in environment
- limited agility and non-shelter seeking
Describe large gregarious social groups in pre-adaptations for domestication
- dominance hierarchy
- males affiliated with group
- these are unfavourable - territorial family groups with separate males
Describe promiscuous matings in pre-adaptations for domestication
sexual signals by movement or posture rather than colour or morphology
Describe precocial in pre-adaptations for domestication
- precocious development, ready to leave the nest at once
- easily separated from parents of altricial young
- prolonged period of parental care
Define altricial
need to be fed in nest, immature etc
What are the reasons for domestication?
recognised human need for
- control of food production
- clothing, labour transport
- religious
- protection against pests
What are the exceptions for the reasons for domestication?
dog
cat - without many important pre-adaptations
How is the dog an exception for reasons of domestication?
may have scavenged around human habitations and ‘evolved’
i.e. selection pressure for the lifestyle leading to taming etc.
How is the cat an exception for reasons of domestication?
- Territorial, not living in large social groups, aloof towards humans
- Breeding not so well controlled as in other species and freedom of movement is less restricted – unique commensal relationship with humans?
What are the approaches to the study of effects of domestication on behaviour?
- comparison of wild and domestic stock
- hybridisation
- domestication genes
Describe comparison of wild and domestic stock in study of effects of domestication on behaviour
can wild stock represent wild ancestors of domestic stock?
uncertain origins
extinction of wild stocks
selection acting in wild population since domestication
geographical variation in wild
Describe hybridisation in study of effects of domestication on behaviour
- Verifies existence of differences
- All problems of comparative approach with choice of stock & possibility of heterosis in crossbred giving behaviours that are not the average of the 2 parent breeds
Give 2 examples of domestication genes in study of effects of domestication on behaviour
- Avoidance of humans by captive red foxes inversely related to number of mutant coat alleles in the genotype
- Non-agouti allele associated with ease of handling in Norway rats
->Homozygous black easier than brown hetero or homozygous agouti
Describe the experimental design of comparison of Leghorn and jungle fowl in foraging-social maze test
test arena in cross form
- 2 arms contained sunflower seeds mixed with wood shavings - so needed to work to obtain food
- Other 2 arms commercial layer food (normal diet)
- 1 arm of each food type had an angled mirror to provide simulated companion bird
Describe the results of the Leghorn and junglefowl in foraging-social maze test
- Initial tests with single birds failed due to isolation so pairs tested
describe the experimental design of leghorn & jungle fowl comparison in a hawk model test
- Tested singly in a 1 x 2 m pen with a bowl of wheat seeds in the centre.
- 5 mins adaptation, 5 mins observation
- plastic hawk on string passed over pen at 2.8m height
– observed by fowl for 2 seconds
– behaviour recorded for a further 5 minutes.
What are the results of the leghorn & jungle fowl hawk model test
- Before the hawk model test Leghorns pecked the ground more than Jungle Fowl.
- After the test, Jungle Fowl walked and vocalised more than Leghorns who stood alert for a greater length of time.
Give a summary of the leghorn & junglefowl experiments
- Junglefowl more active in maze and hawk tests
- Easier to induce tonic immobility in Leghorn
- Leghorn less active in restraint test
- Reduced activity in Leghorn interpreted as a correlated response to selection for productivity - Resource Allocation Theory
Describe resource allocation theory
○ Animals often prefer to work for food, even when it is freely available - contrafreeloading
○ Adaptive since wild animals need to invest resources in investigating possible future food sites
- For highly selected, productive domestic animals - unnecessary foraging results in wasted energy, theory suggests selection will divert energy from foraging to production in environments where food supplies freely available
Give 2 examples of behaviours lost during domestications (turkey, hen)
- copulatory behaviour in male turkeys
- non-broody behaviour in hens
describe maternal reactivity in domestic and wild x domestic sows (hybridisation) study
- 14 sows sired either a Yorkshire or wild boar
- Observed nursing behaviour
- Playback of calls by trapped piglets, isolated piglets or teat fighting calls
Human in nest test
give an example of enhancement of behaviour
- dogs bark 2.3% more than wolves
- dogs bark in many contexts, perhaps trying to solicit attention from humans - barking can be learned
Describe the reasons why dogs may bark more than wolves
- human selection for guarding ability
- linked genes
- domestic environment elicits more barking/ontogeny of barking
Describe how genes can be linked to barking
- neotony/paedomorphosis - young wolves bark and vocalise more - dogs stuck in adolescence
- belyaev foxes
describe behavioural neoteny in barking in wolves/dogs
- selection for tameability related to neoteny
- behavioural neoteny prerequisite for retention of a placid temperament into adulthood
- adolescent wolves bark much more than adults
describe how selection for tameability is related to neoteny
- Suggests neoteny is a prerequisite retention of a placid temperament into adulthood
- Management systems provide many of animals needs without need for aggressive behaviours or attainment of social dominance
Describe how behavioural neoteny is a prerequisite for retention of a placid temperament into adulthood
- Young animals may be conditioned to retain juvenile behaviours
- Raise threshold of adult behaviours by reducing threshold for JB
- Rearing of juveniles away from adults - delay / impair development
What are the primary effects of domestication on behaviour in:
dogs
pigs/sheep/cows
horses
- Dogs - docility, fetching herding, aggression
- Pigs, sheep, cows - reduced reactivity docility & production traits
Horses - speed and reactivity, performance
Describe how domestication accelerates developmental rates
- accelerated sexual maturation
- accelerated growth and maturation rates
- accelerated behavioural development
Describe how domestication causes accelerated sexual maturation
- Selection under domestic environment
- Absence of social competition from older, dominant animals
- Related to better nutrition - captive wolves will breed as early as 9 months, 2 years in wild
Describe how domestication can lead to accelerated growth and maturation rates
- more energy directed towards growth
- higher ADG often associated with abnormalities such as leg weaknesses
describe how domestication can lead to accelerated behavioural development
- Mongolian gerbils reared in cages were more active than those reared in dark burrows
- Earlier visual stimulation than in wild
Describe how domestication can lead to retarded behavioural development
Some processes have become more prolonged longer periods of social bonding in domesticated foxes
describe developmental domestication (post-natal)
- domestication supposedly seeks precocial vs altricial species
- many domestic species altricial
describe how the horse is developmentally precocious
- can be standing and moving in relatively short period of time
- suckling and predator avoidance
- internal mapping systems
Describe early human mappings
- Accurately look at an object (saccade)
- Accurately reach for an object
- Much of early development centred around mapping systems and in particular fine tuning mapping transforms that facilitate accurate saccades and reaching
- Reasonably complex process
Describe saccade
- basic level requiring accurate motor transforms based on current eye and hand position
- if an object in peripheral vision appears and we saccade to that, this requires the point of the object in peripheral view is transformed accurately in motor commands
describe reach
- hand position and object position must be estimated accurately within a common reference frame (retinotopic) and the 2 position vectors subtracted in order to generate the correct motor vector to get the hand to the object
how do humans become accurate?
high repetition and correction of error
describe mappings in the horse
can move head and body towards objects located within its retinotopic map
same for all precocial species
Describe the linear and serial buildup of competences
- certain abilities must be established before others can develop e.g., walk before run
- trend of innate to learned
Describe play behaviour
- Musculoskeletal development and general condition
- Social interaction-dominance hierarchy
- One of the most important activities that facilitates development of a range of physical & cognitive competences
what is critical to behavioural development and behavioural trajectory
effect of early handling, weaning, diet and husbandry environment
