Often animals are hand-fed, without any form of enrichment or effort to obtain their food. I caught myself last time doing the same while feeding the otters. So the next day I used the food, normally chopped fish but this time as a whole, and inserted it in a sandwich feed board. The otters, normally done with eating within max 15 minutes, were now busy for 2 hours obtaining all the fish. And most striking was that the time I spend on it was not much more than I usually do. Off course the otters spend some time doing other stuff in between as well, but I achieved an increase in appetitive behaviours of more than 400%. So why don’t we make every feeding opportunity enriching?
Foraging behaviour compared: wild versus captivity
When we enrich animals, we want to stimulate species-specific wild behaviours, preferably in the same degree as is shown in the wild. When we compare captive animals with wild conspecifics, research studies shows that there is 20% – 75% less foraging behaviour observed in captive animals. With other words, they spent not near as much time on food-related behaviours as their wild conspecifics do. So when an animal is not busy performing appetitive and consummatory behaviours, it will be replaced with other behaviours. And when an animal is bored and not challenged or stimulated enough, it can be replaced with adverse abnormal behaviours and stereotypes. So animals must spend their species-typical time budget on forage behaviours. Not only the total time spent is significant, but the natural feeding times and forage frequency should be considered as well. When animals naturally feed with pre-dawn hours may also need to be fed in pre-dawn hours in captivity, to encourage species-typical diet consumption and promote natural behaviours correspondingly. The same with feeding frequency. It is not logical, for example, to feed a lion four times a day when naturally it hunts once a day (and often less). In the same way, an otter shouldn’t be fed once when its conspecifics hunt and collect food multiple times a day.
No more free lunches – contrafreeloading
With that said, it is time to stop with completely free lunches. And with free lunches, we mean stop feeding without a certain effort for the animal. Does this mean we need to use food-based enrichment daily? Yes! But this is not that hard to implement. Choose a form of enrichment device (puzzle feeder or some sort) where you can place food in easily. It would be best if the enrichment device is also easy to install and that it can be refilled throughout the day if necessary. And at its best, when an animal tries to obtain the food, it should stimulate appetitive behaviours that are typical for the species in question. At the same time, remember the contrafreeloading concept. Animals most often want to take a certain effort to obtain their food. So let’s use it then! Thenceforth, the animal has more focus on the enrichment device and is more behaviourally satisfied so that at the same time, there is less attention for the zookeeper (i.e. decrease begging behaviours) and probably decreased pre-feeding anticipation. Especially when there is a certain variation in the type of enrichment and when given. Keep in mind that when an animal is not known to this concept, you carefully implement this concept in steps and observe its effect every step you take. An animal can be very frustrating when it not understand the enrichment device and is not able to obtain its food, which can lead to stress and aggression (especially in a social group of animals). To give this principle more guidance, implement it in an enrichment plan can be practical.
Should food be chopped?
A bit of a side-topic but absolute as relevant as the above is the question: should food be chopped? Plowman, Green and Taylor (2008) explored what the reasons are for chopping food and if the food even should be chopped? Regular practice in many zoos and facilities is to chop food into small pieces even if the animals are capable of processing much larger items. This widespread belief is done on the assumption that 1) it reduces aggression and enables all individuals in a group to obtain enough of each food type, 2) it enables food to be scattered more easily across large areas of the enclosure to encourage foraging behaviour and prolong feeding time and 3) it prevents wastage caused by animals taking one bite and discarding the rest of a large item. With not examined for every species, these statements are not supported by research findings. Even conversely, some research resulted in the opposite of these statements. One study concluded that intra-specific aggression is significantly decreased when whole food was provided and an increase in food manipulation behaviour (Shora, Myhill and Brereton, 2017). In another study is stated that mean dietary diversity consumed was increased with presenting of whole food items, as did time spent feeding, and even an increased total consumed amount of food (Smith, Lindburg and Vehrencamp, 1998). So it seems that chopping food is not necessary for these widespread beliefs and that you can consider giving food as whole products to increase time spent on feeding, as their wild counterpart does.
Food used in behavioural enrichment
To conclude, I’d like to give a final recommendation. When using food-based enrichment, often additional or novel food items are used above their total diet. When implementing contrafreeloading to increase forage time, all food used for behavioural enrichment must be taken from the calculated diet so overfeeding followed by obesity will be unlikely to occur. On the other hand, when increasing the difficulty of food items collection and increase the physical challenge to obtain food, the energy use of an animal will increase as well in contrast to a non-stimulated animal. So be aware that food must be in relation to the condition of the animal, and needs to be adjusted when implementing these concepts.
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