Fundamental Behaviour 1_170924

• Learning objectives include the ability to describe how animal behavior relates to biology
• Explain natural selection's role in shaping behavior, differentiate between normal and abnormal behavior, and identify behaviors indicating pain, welfare issues, and sickness
• Also understand how infectious diseases alter behavior

Tail-biting in Pigs

• Tail-biting in pigs exemplifies an abnormal and harmful social behavior
• Can lead to pain, secondary infections, impaired growth, death, carcass condemnation
• Results in stress and economic losses estimated at £3.5 million per year

Behavior as Cause and Indicator

• Behavior can cause health and welfare problems
• Behavior can indicate health and welfare problems
• Examples of where behavior can cause problems; pigs tail-biting leading to pain, horses crib-biting causing tooth wear, hyper-aggression in pigs leading to injury, calves cross-sucking resulting in teat malformation, and ewes rejecting lambs potentially causing starvation and death
• Examples where behavior can indicate problems: pigs tail-biting, horses crib-biting and calves cross-sucking
• Other indicators in dogs such as separation anxiety, urine spraying in cats, and sickness behaviors

Importance of Understanding Animal Behavior

• Identifying housing and husbandry practices linked to health and welfare risks
• Spotting abnormal behavior indicating health and welfare problems requires understanding of how behavioral changes are caused by disease

Niko Tinbergen's Four Questions

• Niko Tinbergen proposed four complementary causes to explain animal behavior:
• Mechanism: How is behavior achieved? How is it brought about in the body? What are the underlying physiological mechanisms, genetic basis, motivational control and hormones?
• Function: What is the survival benefit? What is its fitness advantage? Why has it evolved?
• Evolution: How did the behavior evolve? Where has the behavior come from? What is its phylogeny?
• Development: How did it develop in the animal? How does the behavior develop during an individual's lifetime?

Examples of Tinbergen's Questions

• Mechanism: Increasing day length influences hormone levels and air flow through the syrinx, and subsequently the membrane vibrations
• Function: Starlings sing to attract a mates for breeding
• Evolution: Starlings songs likely increased in complexity over time
• Development: Starlings sing because they learn the songs from their parents and neighbors

Natural Selection and Behavior

• Natural selection leads to behavioral adaptation to the natural environment
• Adaptations are changes in an animal which are brought about during evolution by the process of natural selection

Genetic Influence on Behavior

• Breed experiments show a genetic influence on behavior, e.g. brood care behavior in bees
• Hygienic bees uncap cells and remove diseased pupae
• Unhygienic bees don't uncap cells or remove dead pupae
• Inheritance of 'hygienic' bee behavior involves two independently segregating genes with two alleles each
• One gene controls uncapping cells, with a dominant unhygienic allele (u+) and a recessive hygienic allele (u-)
• The other gene controls removing larvae, with a dominant unhygienic allele (r+) and a recessive hygienic allele (r-)

Quantitative Traits

• Some behaviors, like nest material collection in lovebirds, do not occur in two discrete states, but are actually complex
• The mixed behavior of offspring suggests control by a larger number of genes/environmental factors
• Quantitative polygenic traits
• It is impossible to determine genotype from experiments
• Instead, use breeding experiments to investigate heritability

Influence of genes on behavior

• Most behaviors are influenced by many genes, making them polygenic traits.
• Evidence comes genetic effects from hybridization/breeding experiments
• Can also come from strain/breed comparisons or Quantitative trait locus analysis
• Altered behaviours in the presence of chromosomal abnormalities
• It's understood that genes affect behavior via proteins
• Some examples are: peptide hormones, steroid hormone receptors, pigments, and transcription factors

Domestication and Behavioral Adaptation

• Artificial selection, unlike natural selection, has not often prioritized selecting for specific behaviors
• Naturally-evolved behaviors may now be maladaptive, creating a biological mismatch for modern-day welfare
• Livestock are often restricted in behavior regarding maternal care, dust bathing, and limited socialisation

Assessing the Restriction of Behavior

• Research approaches to asses restrictions:
• Compare the behavior of captive domestic species with their ancestral specifies
• Examine behaviour of domestic animals released into wild environments

Understanding Normal and Abnormal Behavior

• "Normal behavior" describes the natural behavioral characteristics of a species in question
• Ethograms inventories behaviors
• Assessment using extensive, semi-natural conditions
• "Abnormal behavior" describes behavior seen only in captivity or that differs widely from the behavior of free-living individuals
• Abnormality is away from statistical norm of behaviors

Indicators and Causes of Abnormal Behavior

• Abnormal behavior indicates pathology, physical trauma, sickness
• Can indicate maladaptive modification
• Also indicate learnt and adaptive modification
• Can develop due to behavioral restriction ultimately leading to failed adaptation and 'stereotypy'

Stereotypies

• Stereotypies are abnormal repetitive, invariant behaviors without obvious goal or function
• Used as indicators for welfare problems, such as crib biting in horses, and tail biting in pigs

Behavioral Responses to Disturbance, Pain, and Distress

• Include low activity, hiding, fleeing, avoidance/escape/struggle, immobility, and distress signals
• Predators can often see tell-tale signs of potential vicitms
• Prey species learn to hide vulnerabilities

Clinical Assessment of Pain

• Behavioral signs of disturbance, pain, and distress include visual analogue scales (VAS) and behavior scoring, which can be generic and species specific behaviors
• Common systems include examination of posture, vocalising, temperament and locomotion
• Can also involve lameness scoring

Sickness Behavior

• Behavioral changes can precede clinical signs, demonstrated in Huntington's Disease mice
• Sickness behavior is not disease-specific, involving anorexia, increased thirst threshold, sleepiness and depression, reduced grooming etc
• Further effects include reduced social exploration and changes to learning

Pro-inflammatory Cytokines

• Pro-inflammatory cytokines acting in the brain are related to sickness behaviors
• Involves anorexia, increased thirst threshold, sleepiness, depression, reduced grooming, reduced social exploration, and learning and memory changes