Promoting happiness: A shift in zoo animal welfare

Zoos and aquariums are presently important players in wildlife conservation, both in the field (in situ) and at home (ex situ). A key concern in those institutions is how to evaluate animal welfare. Unlike humans, you cannot simply ask a non-human animal how they feel. Historically, approaches to animal welfare in zoos focused on looking for evidence of bad welfare, of unhappiness, or of stress. But just as human psychology has increasingly begun to recognize the importance of positive psychology alongside the study of mental distress and disorder, zoo biologists have begun to think about animal welfare in terms of promoting happiness rather than avoiding stress or discontent.

The easiest way to assess welfare is through observing behavior. It’s a non-invasive measurement technique, and does not require any specialized equipment. In a recent essay in the journal Zoo Biology, San Francisco Zoo Vice President of Wellness and Animal Behavior Jason Watters argues that a focus on behavioral indicators of positive welfare will help zoo keepers and curators better understand when an animal experiences positive affect. Or put more simply, when they feel happy. One way in which zoo keepers and curators might identify evidence of positive affect, he says, is through anticipatory behavior.

Put most simply, anticipatory behavior is an indication that an animal expects a reward, such as food or social interaction, and is therefore a real-time indicator of an animal’s own perception of their well-being. But relating anticipatory behavior to welfare is a tricky proposition.

Anticipatory activity itself may be rewarding. Anticipation, Watters argues, activates the dopamine and opioid systems, a set of neurobiological pathways involved in predicting rewards. Put into human terms, the feeling of anticipating an ice cream cone may be as enjoyable as the ice cream cone itself, as long as the ice cream isn’t withheld, which would have the effect of transforming a reward event into a frustrating or stressful one.

On the other hand, animals (and people) look forward more to positive events that are rare than ones that are common. The intensity of anticipatory behavior might therefore reflect how “important” an expected event is to an individual animal. “One might expect that when there are very few occurrences or types of positive events in an animal’s life, those events that are relatively mundane to animal keepers – like feeding – become exceptionally important to the animals themselves,” writes Watters. Indeed, lots of research demonstrates that animals that are deprived of food or social interactions show increased food-related anticipatory activity.

These two phenomena are slightly contradictory in terms of animal welfare. If anticipatory behavior is especially intense or vigorous, it might actually reflect overall worse welfare, because rewarding events are so salient or rare, even if it can be pleasing in the moment. But when rewarding events are more common, anticipatory behavior may appear more subdued. That may reflect better overall welfare.

What that means is there’s a welfare tradeoff between intensity and frequency. Using anticipatory behavior to accurately assess welfare requires long-term, contextual observations. Animals who appear to be extremely excited may actually be worse off, in the long run, than those who experience more frequent but less extreme anticipation. “In essence,” says Watters, “the manner in which an animal expresses anticipatory behavior tells us just how much the animal believes that it ‘needs’ the coming positive experience.”

A visual description of the frequency-intensity tradeoff in terms of anticipatory behavior and animal welfare. (via Watters, 2014)

A visual description of the frequency-intensity tradeoff in terms of anticipatory behavior and animal welfare. (via Watters, 2014)

While most species – fish, reptiles, amphibians, birds, and mammals – can express their anticipation in overt, observable ways, the specifics of a given species also must be considered. Species whose natural habitats are themselves less predictable may have evolved to display anticipatory behavior under different conditions than those who evolved in more stable environments. And that’s not to mention differences in the personality of individuals.

Watters’ essay is a researcher’s call to arms. As those who are responsible for managing the welfare of animals begin to think more seriously about promoting happiness rather than avoiding unhappiness, researchers will need to establish taxon-specific protocols for measuring happiness. – Jason G. Goldman | 15 August 2014

Source: Watters J.V. (2014). Searching for behavioral indicators of welfare in zoos: Uncovering anticipatory behavior, Zoo Biology, 33 (4) 251-256. DOI:

Header image: Allen’s Swamp Monkeys, San Diego Zoo, copyright Jason G. Goldman