Behaviour of Zoo Animals

Jeff Nightingale BSc (Hons), M.I.A.T. M.I.A.C.E.

• Zoos provide a good place to study animal behaviour

• Often easier than in the wild• Particularly true for rare or remote species

Learning & Zoo Animals• Habituation – reduction in response to repetitive or constant stimulus

• Classical conditioning – association of existing response to a new stimulus

• Operant conditioning – new response to an existing stimulus

• Imprinting – young animals learning of species identity, sex & relatedness to others

• Social learning – learning from others

Zoos and Animal Learning• Habituation – e.g. Reduction in fearful behaviours to people

• Classical conditioning – sound of food preparation, familiar keeper & food

• Operant conditioning – positive reinforcement training (shows, veterinary procedures, transport)

• Imprinting – hand-rearing, stereotypies, breeding & reintroduction

Animality?• Breeding success – black rhino• Dominant scores predicted breeding success• Males: negative correlation• Females: positive correlation • Behavioural variation – cheetah• Tested with novel objects (e.g. traffic cone)• Three temperament components (tense-fearful; excitable-vocal; aggressive)

accounted for 69% of observed variation in behaviour

Animality & Captivity• Select for individuals suited to captivity?• Improved welfare• Consequences for reintroduction?• Few studies on animality & reintroduction• Swift foxes: boldness & survival – negative correlation• Bighorn sheep: boldness & survival –positive

correlation (ewes)

Stimuli & responses• Temporal & spatial variation• Stimuli allow animals to choose appropriate responses• Improved captive environments if we know which stimuli

are important• Species sensitivities & reactions• Ultrasound• UV vs. Warmth in spiny-tailed iguana

Social environment• Expression of natural behaviour• Communication• Opportunities for social interaction depend on group demography• Different or similar to that in the wild?• Social behaviour often an indicator of influence of zoo environment

on welfare

Conspecifics• Human rearing• Lone• Social group – Unnatural• Flamingos >20 breed well• Japanese macaques: female monopolized male• Bachelor gorilla groups – often high cohesion• Natural

Heterospecifics• Few quantitative studies• Ungulates showed greatest aggression between distantly related

species• Columbus zoo – lions partially in view to ungulates, increased

vigilance when lions in view

Enclosure Size• Mostly smaller than wild home ranges• Comparative enclosure studies – different furnishings, group size/

structure• Wolves – rest more in larger enclosures• Przewalski’s horses – lower aggression, grooming & pacing in larger

enclosures

Enclosure Use• Content versus size• Wild boar: mud and shade

Food preparation & presentation• Scatter feeding & aggression / monopolization• Whole foods & handling• Multiple feeds & increase in exploratory / locomotive behaviour

• Timing & predictability – increased aggression / pacing prior to feeding (primates fed twice a day)

• Effects of a delay on “predictable” meals?

Housing & Husbandry Changes• Move to more naturalistic enclosure – e.g Hanuman langurs at

London• Typically increased activity & lowered aggression / interaction• BUT in a juv. gorilla a move from a concrete grotto to naturalistic

exhibit some reduced stress-related behaviours (coprophagy & regurgitation/reingestion) self-clasping increased

• Enclosure switching – done regularly it can increase exploration / activity

• Births, deaths, removals all also influence behaviour, but often qualitative observations

Abnormal Behaviours• Definitions• “Uncommon or even absent in free-ranging animals”• “Rare or unusual”• “Lacking in function and maybe harmful to the animal, possibly as a

consequence of an underlying pathology”• Rare with respect to what? The wild?

Abnormal or undesirable?• Regurgitation & re-ingestion in gorillas• 65% of captive gorillas, thus “normal” in relative sense• “undesirable” avoids negative assumptions of “abnormal”

Abnormal Behaviours in a zoo context• Meyer-Holzapfel (1968)• Abnormal escape reactions• Refusal of food• Abnormal aggressiveness• Stereotyped motor reactions• Self-mutilation• Abnormal sexual behaviour• Perversion of appetite• Apathy• Abnormal mother-infant relations• Prolonged infantile behaviour & regression

Qualitative vs Quantitative Abnormality• Erwin & Deni (1979) distinguish• Qualitative – different in form e.g stereotypies, self-biting • Quantitative – elevated or depressed levels of an otherwise normal

behaviour e.g. hyper-aggression, inactivity

Abnormal Behaviour & Welfare• Presence of abnormal behaviour often taken to mean animal is

suffering or that its welfare is or has been compromised• BUT many abnormal behaviour shows great diversity in motivation,

physiological, developmental & environmental correlates• Each abnormal behaviour best considered separately • Stereotypies have a clear link with welfare BUT it’s unclear what that

link is!

Common Stereotypies• Pacing – carnivores• Licking – ungulates• Surface swimming – rays• Feather pulling – parrots

Enclosure Size & Stereotypies:Why some species are worse

than others• Carnivores• Home range predicts frequency of stereotypies (Clubb & Mason 2003)• Not result of thwarted foraging/hunting but frustrated escape attempts?• Better enclosure design to allow more natural behaviour?• Some species are unsuitable to be kept in zoos?

Stereotypies: What to do?• Prevent them e.g. use bitter chemicals on

licked areas• Provide enrichment• Often trial & error• Effective in ca. 50% of cases• Often tailored to needs of the individual

concerned• Sample size, methodological issues,

experimental design etc make drawing any general conclusions about effectiveness of specific treatments hard

Comparison to the wild• What is wild?• Enclosures were once mainly concrete & bars• Move towards naturalistic enclosures, first from human view

point, increasingly from what animals do in the wild e.g. Goeldi’s monkey

• Observers & method influence behaviour• Small sample sizes for both may give atypical results,(Veasey

et al 1996)

Why compare?• Welfare• Is wild welfare best?• Does expression of a behaviour improve welfare?• Does inability to express a behaviour decrease welfare?• No clear answer – so caution required!

• Species typical behaviours may be required for reintroductionZoos may unwittingly select for atypical behavioural traits ie animals able to cope with captivity

Summary• Behaviour can provide information about welfare• Zoo observations of behaviour often easier than field ones• Aspects of zoo environment may alter behaviour (enclosure

size, complexity, food, husbandry, social group) – but details are scant (apart from primates)

• Suboptimal environments may result in abnormal behaviours, naturalistic enclosures reduce the instances of this

• Potential benchmark for interpreting behaviour in zoos is with wild conspecifics – but caution needed