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2.3 Human Impact on Animals

2.3.1 Animal Welfare Science Animal Welfare Science – Definitions and Concepts

Broadly speaking, the science of animal welfare asks three big questions:

Are animals conscious? How can we assess good and bad welfare in animals?

How can we use science to improve animal welfare in practice? (DAWKINS 2005/ 2006, p. 77)

Animal welfare is about as easy – or difficult – to define as is human welfare. Good welfare starts with physical health, but it requires more than that, for it also implies that animals have positive (pleasure, contentment) rather than negative emotions “such as fear or frustration, which we humans label ‘suffering’” (DAWKINS 2005/ 2006; p. 77).

BROOM (1986, 1988a, b) defined the welfare of an individual as

“its state as regards its attempts to cope with its environment”.

It is important to notice that the definition is phrased in such a way that it “refers to a characteristic of the individual at the time” (BROOM & KIRKDEN 2004, p. 2).

Coping in this context means to have control of mental and bodily stability (BROOM & JOHNSON 2000) which includes normal regulation of body state as well as emergency responses.

The “state as regards attempts to cope” refers to both how much has to be done in order to cope with the environment and the extent to which coping attempts are succeeding (BROOM & JOHNSON

2000, p. 74). There are various methods used by individuals who try to counteract adverse effects or difficult conditions. Attempts to cope include a variety of behavioural responses, as well as emergency physiological responses, the functioning of body repair systems and immunological defences.

Extreme examples of indications of (prolonged) failure to cope are impaired life expectancy and reduced ability to reproduce (BROOM & JOHNSON 2000). If the failure to cope is only short-term (e.g., danger-induced adrenal activity for a limited period), it is unlikely to result in impaired life expectancy, but it does cause poor welfare with respect to the individual concerned. Likewise, the absence of fitness reduction does not automatically suggest good welfare: WIEPKEMA (1985, as quoted in BROOM

& KIRKDEN 2004, p. 3) lists pain, fear, and difficulty controlling interactions with the environment (e.g., because of overstimulation or too much unpredictability) as welfare-reducing aspects which do not necessarily have an impact on biological fitness. And WECHSLER (1995, p. 131) states:

“From an evolutionary perspective adaptation has failed when there is a reduction in biological fitness, i.e., in the number of offspring. This type of argumentation is, however, not sufficient to judge animal welfare. Ultimate causes of behaviour have to be differentiated from proximate causes (DAWKINS, 1983; WECHSLER, 1993). The animal’s behavioural organisation is directed at proximate goals which are only correlatively related to the ultimate functions of behaviour. Therefore, what matters for the animal is to reach these proximate goals and coping behaviour represents a set of strategies that, at least in a natural environment, increase the probability of attaining such goals.”

If an animal’s coping systems succeed only with difficulty (taking much time and energy), welfare of that animal is poor during the process (BROOM 1988b), and may remain poor until complete recovery has been achieved.

In determining an animal’s welfare state at a given time, the assessment of physical health is relatively straightforward, but the ‘emotional part’ of the requirements (see above) has proved far more difficult to tackle.

Addressing this problem, one of the main types of study in animal welfare science focuses on examining animal emotions. These studies use a variety of ways of ‘asking’ animals what they do and do not want. Preference tests, in which animals are given a choice of aspects of their environment and the outcome is monitored, were first employed by HUGHES and DAWKINS (e.g., HUGHES 1975 quoted in DUNCAN 2006; DAWKINS 1977), and have since then been ridded of certain

pitfalls associated with them (e.g., choices deleterious to the animal’s health). According to DUNCAN

(2006) preference tests give a good first indication of what the animals feel about various aspects of their environment.

As a follow-up to preference tests, studies measure the strength of the preference, for instance, by ‘increasing the price the animal is willing to pay’ (i.e., testing how hard the animal will work to achieve their goal). ‘Obstruction tests’ may involve pushing past an obstruction or pushing open a weighted door (e.g., NICOL & GUILDFORD 1991; MASON & al. 2001), while in ‘operant responding’

the strength of the animals’ motivation is measured in terms of ‘just how often they will repeat an action’ they have learnt to associate with a reward (e.g., DAWKINS & BEARDSLEY 1986). Evidence from such studies strongly suggests that animals do have preferences and are generally prepared to work for them.

A further fact arising from these investigations concerns the frequently high inter- and intra-individual as well as situational variability of preferences. Although these laboratory or on-farm studies are not easily transferred to the field setting, the important take-home message would seem to be that individuals might have to be considered individually.

Moreover, if animals are acknowledged to have preferences and be able to indicate them in a

‘graded’ fashion (i.e., stronger preference for this, weaker preference for that within a given set of circumstances), it seems reasonable to assume the animals equally capable of expressing a gradation with respect to disturbing stimuli (e.g., conspecific disturbance, different types of human visitation).

Animal welfare scientists have given much attention to the concept of stress (e.g., BROOM & JOHNSON

2000; BROOM & KIRKDEN 2004; FRASER & BROOM 1990; KOOLHAAS & al. 1999; VON BORELL & al. 2007).

Measurements of stress responses have involved a variety of parameters, e.g., behaviour, heart rate, the adrenal axes and other hormones (review in BROOM & JOHNSON 2000). BROOM & JOHNSON

(ibid., p. 178) define stress as being

“an environmental effect on an individual which overtaxes its control systems and reduces its fitness or appears likely to do so. Fitness reduction involves increased mortality and failure to grow or reproduce”.

Fitness is measured as lifetime reproductive success. It should be noted that (fitness evaluations being outside the scope of THISTHESIS) the term ‘stressor’ is used in a broader context here (like, for instance, in TARLOW & BLUMSTEIN 2006/ 2007; see section 2.3.3), referring to stimuli that cause measurable disturbance responses but do not necessarily permit predictions with respect to ultimate fitness consequences.

Some of the important points Animal welfare science is making have contributed to THISTHESIS. The conceptual fact that welfare is a characteristic of an animal (e.g., FRASER & BROOM 1990), not something given to it, emphasises the relevance of individual-based approaches to the assessment of the impact of human disturbance on animals.

Research on coping strategies and styles, i.e., different responses to the same (aversive) stimulus (e.g., “escape, remove59, search, wait60”: WECHSLER 1995; “proactive vs. reactive”: KOOLHAAS & al.

1999; WINGFIELD 2003) has demonstrated that both species-specific strategies (e.g., responses

59 including increased aggression 60 including apathetic behaviour

of prey species vs. predator species) and individual-specific responses have to be taken into account when investigating human impact. As BROOM (1988b, p. 16) states:

“Each individual animal has several alternative methods of trying to cope with adversity and individuals differ in the methods which they favour.”

With respect to stress, JORDAN (2005, p. 518) points out: “Scientists argue that stimuli with which the animal can cope are essential to keep the coping process in good working order, and the dividing line between what is beneficial and what is harmful varies for each individual.”

The concept pursued by animal welfare science also introduces a measure more sensitive and more readily accessible than lifetime reproductive success and/or its components (e.g., life expectancy and inclusive fitness), employing proximate measures like behavioural and physiological parameters (e.g., BROOM & KIRKDEN 2004; DAWKINS 1997, 2003, 2005/ 2006; DUNCAN

2005; MENDL 2001).

In doing so, the concept challenges the assumption that negative human impact on animals can be considered inconsequential as long as the overall population remains ‘on the right side of extinction’ 61.

The validity and applicability of various behavioural and physiological parameters in the assessment of animal welfare have been reviewed by a number of animal welfare scientists (tab. 2-4). Even though the respective studies have been conducted on laboratory or farm animals, the conclusion that there is no single measure of welfare (e.g., BROOM & JOHNSON 2000; DAWKINS 2005/ 2006;

SWAISGOOD 2006/ 2007) is transferable to field conditions. JORDAN (2005), for instance points out the problems of wild animals ‘masking’ injuries, and of different species reacting to the same stimulus in different ways. SWAISGOOD (2006/ 2007, p. 141) likewise notes that “no single measure provides the ‘silver bullet’ for understanding welfare” and stresses the necessity to monitor a “suite of behavioral [sic] variables in concert” (ibid.) to characterise an animal’s state.

This has led to the inclusion of both a broad array of behavioural parameters as well as one physiological (i.e., heart rate) parameter in THISTHESIS.

61 The opposite suggestion, viz., that disturbance has sufficiently negative effects only if the species/ population as a whole is endangered, has been put forward by some researchers (e.g., NISBET 2000).

62 WEARY & al. (2006) use a classification like this for behavioural responses to pain. Animal Welfare Science – Behavioural Measures of