The amount of risk animals perceive in a given circumstance (i.e. their degree of ‘fear’) is a difficult motivational state to study. While many studies have used flight initiation distance as a proxy for fearfulness and examined the factors influencing the decision to flee, there is no general understanding of the relative importance of these factors. By identifying factors with large effect sizes, we can determine whether anti-predator strategies reduce fear, and we gain a unique perspective on the coevolution of predator and anti-predator behaviour. Based on an extensive review and formal meta-analysis, we found that predator traits that were associated with greater risk (speed, size, directness of approach), increased prey distance to refuge and experience with predators consistently amplified the perception of risk (in terms of flight initiation distance). While fish tolerated closer approach when in larger schools, other taxa had greater flight initiation distances when in larger groups. The presence of armoured and cryptic morphologies decreased perception of risk, but body temperature in lizards had no robust effect on flight initiation distance. We find that selection generally acts on prey to be sensitive to predator behaviour, as well as on prey to modify their behaviour and morphology.

/pdf/fear-in-animals-a-meta-analysis-and-review-of-risk-5fg0306m8r.pdf

Fear in animals: a meta-analysis and review of risk assessment

https://www.esf.edu/EFB/faculty/documents/Forkmanetal2007reviewoffeartestsinanimals_000.pdf

A critical review of fear tests used on cattle, pigs, sheep, poultry and horses

1: Biological Response to Stress: Implications for Animal Welfare, G P Moberg, University of California, USA 2: Some Issues in the Interpretation of Behavioural Responses to Stress, J Rushen, Dairy and Swine Research and Development Centre, Agriculture and Agri-food Canada, Canada 3: Neoroendocrine Responses to Stress, R L Matteri, J A Carroll and C J Dyer, University of Missouri, USA 4: The Metabolic Consequences of Stress: Targets for Stress and Priority of Nutrient Use, T H Elsasser et al., USDA, Agricultural Research Service, USA 5: Immune System Response to Stress, F Blecha, Kansas State University, USA 6: Hands-on and Hands-off Measurement of Stress, C J Cook et al., Horticultural and Food Research Institute of New Zealand, New Zealand 7: Accumulation and Long-Term Effects of Stress in Fish, C B Schreck, Oregon State University, USA 8: Chronic Intermittent Stress: A Model for the Study of Long Term Stressors, J Ladewig, The Royal Veterinary and Agricultural University, Denmark 9: Quantifying Some Responses to Pain as a Stressor, D J Mellor, Massey University, New Zealand, C J Cook and K J Stafford, Horticultural and Food Research Institute of New Zealand, New Zealand 10: Multiple Factors Controlling Behaviour: Implications for Stress and Welfare, F Toates, The Open University, Milton Keynes, UK 11: Chronic Social Stress: Studies in Nonhuman Primates, S P Mendoza, J P Capitanio and W A Mason, University of California, USA 12: Consequences of Stress During Development, D C Lay Jr., Iowa State University, USA 13: Early Developmental Influences of Experience on Behaviour, Temperament, and Stress, W A Mason, University of California, USA 14: Genetic Selection to Reduce Stress in Animals, T G Pottinger, NERC Institute of Freshwater Ecology, Windermere Laboratory, Cumbria, UK 15: Human-Animal Interactions and Animal Stress, P H Hemsworth and J L Barnett, Agriculture Victoria, Australia 16: Alleviating Stress in Zoo Animals with Environmental Enrichment, K Carlstead, National Zoological Park, Washington, USA and D Shepherdson, Oregon Zoo, USA 17: Understanding the Role of Stress in Animal Welfare: Practical Considerations, T L Wolfle, formerly of the Institute for Laboratory Animal Research, National Research Council, National Academy of Sciences, USA

The biology of animal stress: basic principles and implications for animal welfare.

Populations of Drosophila were trained by alternately exposing them to two odorants, one coupled with electric shock. On testing, the flies avoided the shock-associated odor. Pseudoconditioning, excitatory states, odor preference, sensitization, habituation, and subjective bias have been eliminated as explanations. The selective avoidance can be extinguished by retraining. All flies in the population have equal probability of expressing this behavior. Memory persists for 24 hr. Another paradigm has been developed in which flies learn to discriminate between light sources of different color.

https://www.pnas.org/content/pnas/71/3/708.full.pdf

Conditioned Behavior in Drosophila melanogaster

https://cyberleninka.org/article/n/516450.pdf

Assessing the human-animal relationship in farmed species: a critical review

Bovine cattle from various parts of the world were studied in a physically and culturally homogeneous environment. The animals' approachability by a human in open pastures was associated with breed differences. Dairy breeds were more approachable than beef breeds, while a comparison between European (Bos taurus) and humpbacked (B. indicus) stock yielded equivocal results. Raising dairy breeds for meat and raising beef breeds as milch cows had little overall effect on their approachability. Genetic affiliation was a much more powerful variable than treatment. Under ordinary rearing conditions within a particular ethnoenvironmental medium, it would appear that approachability is a relatively stable property of cattle breeds.

Approachability of bovine cattle in pastures; breed comparisons and a breed x treatment analysis

Domestic cattle have paradoxical tendencies both to approach and to avoid humans Approach (investigating a person lying on the ground) and avoidance (flight distance) were studied in 21 herds of 12Bos taurus, B indicus, andB taurus x B indicus breeds located in a homogeneous, Brazilian environment Seven herds were compared in their investigatory responses to a human and a ball Breed differences were evident for approach and avoidance behavior, which had little relationship with one another When reactions to the person and ball were compared, the responses were also breed specific but negatively correlated Age took precedence over breed affiliation in investigating the human The results were interpreted in a predator-prey context

Responses of cattle to humans in open spaces: Breed comparisons and approach-avoidance relationships

Allonursing in river buffalo, Bubalus bubalis: nepotism, incompetence, or thievery?

Instrumental conditioning of the fruit fly, Drosophila melanogaster.

http://www.grupoetco.org.br/arquivos_br/pdf/communsuck.pdf

Robert M. Murphey

Papers

Approachability of bovine cattle in pastures; breed comparisons and a breed x treatment analysis

Responses of cattle to humans in open spaces: Breed comparisons and approach-avoidance relationships

Allonursing in river buffalo, Bubalus bubalis: nepotism, incompetence, or thievery?

Instrumental conditioning of the fruit fly, Drosophila melanogaster.

COMMUNAL SUCKLING IN WATER BUFFALO (Bubalus bubalis)