Behavior in Domestic Animals Andrew U Luescher Dr med vet, PhD, DACVB, ECVBM-CA Definition of Behavior • Behavior could be defined as that part of regulatory mechanisms that is observable at the level of the entire animal • The relationship between behavior and physiology is similar to the one between physiology and biochemistry Control of Drinking Behavior • Lateral Hypothalamus: Osmoreceptors – Mild dehydration results in increased release of ADH from posterior pituitary – Stronger dehydration stimulates thirst centers • Baroreceptors in cardiac blood vessels – Increase vasopressin (=ADH) release – Via vagus nerve initiate drinking Questions about Behavior • Why do pigs • Stimulus control of wallow in mud behavior • Why do pigs • Motivation wallow in mud • Why do pigs • Behavior genetics wallow in mud • Why do pigs • Evolutionary wallow in mud causes of behavior Causes of Behavior • Stimulus control • Motivation • Genetics (Domestication) • Evolutionary causes (Adaptation) • Effects of experience (Learning) Proximate Causes of Behavior: Stimulus Control Behavior could be classified as to how rigid the association between the behavior pattern and the triggering stimulus is • Reflex • Fixed action pattern • Modal action pattern • Learned behavior Reflex • Consistent, predictable response to specific stimulus • Rigid stimulus-response association • Simple neural pathways • Highly genetically programmed • Involuntary, not influenced by motivation Proximate Causes of Behavior: Stimulus Control • Reflex • Fixed action pattern • Modal action pattern • Learned behavior Fixed Action Pattern (FAP) • Fairly consistent response to a specific stimulus (key stimulus) • Can occur alone or as an element of a behavioral sequence • Influenced by motivation Proximate Causes of Behavior: Stimulus Control • Reflex • Fixed action pattern • Modal action pattern • Learned behavior Modal Action Patterns (MAP) Most species-specific behavior of domestic animals is made up of MAPS Similar to FAP but more variable SR association, and more influence of learning Defined by: • Motor pattern • Releasing stimuli • Motivational factors Modal Action Pattern • Genetically pre-programmed Modal Action Pattern • Variable within limits. Influenced by – Spatial restriction – Availability of releasing stimuli – Learning – Early experience Modal Action Pattern • In absence of natural releasing stimuli: – redirected activity – vacuum activity – Stereotypy/ Compulsive behavior Redirected and Vacuum Behavior Proximate Causes of Behavior: Stimulus Control • Reflex • Fixed action pattern • Modal action pattern • Learned behavior – see lecture on learning Causes of Behavior • Stimulus control • Motivation • Genetics (Domestication) • Evolutionary causes (Adaptation) • Effects of experience (Learning) Proximate Causes of Behavior: Motivation • Animals do not always respond to releasing stimuli • In absence of releasing stimuli, animals may – show appetitive behavior – redirect behavior – perform vacuum activity • Variability of input/output necessitates concept of motivation Models of Motivation • Homeostatic model of motivation: Behavior Program Actual Value Comparison Perception Target (set) Value Variables Influencing Motivation Homeostasis • Control of drinking behavior • Control of food intake: effect of physiological signals on hypothalamus • Temperature control Hormones and Behavior • Priming of the male brain Hormones and Behavior • Melatonin and yearly breeding cycle • Hormones and estrus cycle (estrogen and progesterone) • Hormones and maternal behavior (progesterone , estrogen and prolactin , oxitocin Pheromones and Behavior • Chemical signal, often non-volatile • In urine, skin glands, anal glands, etc • Often need transformation by bacteria Vomeronasal Organ • Perceived through vomeronasal organ, flehmen response • Opens into mouth and nose except dog (mouth only) and horses (nose only) Pheromones and Behavior • Primer pheromones – Physiological effect, e.g., earlier puberty • Signaling pheromones – Immediate behavioral effect on receiver, e.g., individual recognition Time Since Behavior was Performed Last • Increased frequency and intensity with increased deprivation time • Only valid within certain time limits Circadian Rhythms • Internal biological “clock” with a phase length of approximately (circa) 24 hours • “Clock” needs to be reset every day by external stimuli like light/dark cycle Releasing Stimulus • The releasing stimulus (target) enables the animal to perform a behavior • Presence of the releasing stimulus also motivates animal to perform the corresponding behavior Social Facilitation • One animal performing a behavior motivates other animals to perform the same (type of) behavior • Results in synchronization and successful competition within group Learning and Motivation • Conditioned, discriminatory and reinforcing stimuli • See lectures on learning Effects of Motivation • Animal will be motivated for appetitive and consummatory behavior, i.e. all behaviors related to that motivational system • In animal husbandry, frequently only consummatory behavior is accommodated • Examples: feed search, nest building Causes of Behavior • Stimulus control • Motivation • Genetics and Domestication • Evolutionary causes (Adaptation) • Effects of experience (Learning) Domestication • Involves genetic changes in response to association with humans, captive environment and husbandry, and developmental events reoccurring during each generation. Domestication: Genetic Changes • Adaptation (natural selection) to co-habitation with humans • Genetic adaptation to captive situation • Relaxation of natural selection pressure • Inbreeding • Genetic drift • Artificial selection Times of Domestication • Wolf 12,000 • Bezoar Goat 10,000 • Sheep? 9,000 • Eurasian Boar 9,000-11,000 • Auerochs 9,000 • Przewalsky Horse 4,000- 6,000 • Libyan Cat 4,000- 5,000 • Red Jungle Fowl 4,000 • Turkey 1,000 Effects of Domestication • Behavior change due to physical change • Hypertrophy or Hypotrophy of behavior • Decreased selectivity for releasing stimuli • Disruption of behavior sequences Effects of Domestication • Neoteny – retention of juvenile characteristics that is produced by retardation of somatic development – prolonging juvenile developmental stages (e.g. allometric growth of skull) or arresting development at a juvenile stage (e.g. predatory behavior) Neoteny in Various Breeds of Dogs Effect of Domestication on Behavioral Repertoire of a species • Generally surprising little change: Most behavior patterns are still intact, no new patterns have developed • Example: periparturient behavior in sows Causes of Behavior • Stimulus control • Motivation • Genetics (Domestication) • Evolutionary causes (Adaptation) • Effects of experience (Learning) Arguments for Evolution Theory • There is considerable variation among individuals belonging to any population of animals of the same species • Much of this variation is genetically inherited Arguments for Evolution Theory • There are many more individuals born in each generation than can survive to maturity It Follows That... • Individuals are not equally likely to survive • Individuals with traits that make them best fitted (most successful) to that environment survive • They are more likely to reproduce • Their genes will spread through the population Example of Natural Selection Resulting in Adaptations • Peppered Moth – Naturally, very small percentage are black. Select appropriate background Example of Natural Selection Resulting in Adaptations • Peppered Moth – England 1895: 98% black in industrial areas Cultural Transmission • Traits can be passed on from one generation to next through learning = cultural transmission Cultural Transmission • Many traits have a component of both (e.g., bird song) Sexual Selection • Sexual selection occurs in species with differential input into parenting. • The partner of the gender that puts more effort into parental care becomes a limited resource. It is choosy, other sex develops features to attract partners and out-compete competitors.
Pages to are hidden for
"principle"Please download to view full document