Animals have physiological needs such as drinking, eating and sleeping. If we don’t want our pet to fall ill, all these needs must be covered. But we may not be aware that animals also have behavioral needs, which are important for their mental health.
It is common to see gorillas in captivity vomiting up their food and then swallowing it again. In the wild, they spend most of the day feeding, because their diet consists mainly of leaves, which are of low nutritional value. In some zoos, gorillas may eat more high-energetic food, which covers their nutritional needs, but this does not address their behavioral needs. By nature, gorillas eat for many hours and when they cannot do so, they develop this aberrant behavior.
Another example is big cats that pace around in cages, because in the wild they would walk for miles. Humans also have behavioral needs, such as the need to socialize — which became very apparent during the Covid-19 pandemic. Anyone who has lived through a lockdown knows how dangerous it is for mental health not to be able to carry out this natural behavior.
In recent years, there has been growing concern over the welfare of captive animals. This has led to greater effort to enrich their environment and to encourage them to behave as they would in the wild. For example, in many zoos and reservations, food is now hidden from primates, which means they have to spend more time looking for it.
No natural behaviors
Interestingly, there is one species that is not often discussed when analyzing the welfare of captive animals: domestic dogs. When dogs live as pets with humans, they cannot be considered to live freely, as they do not choose where they live, when to go outside or with whom they interact. They are often confined to a limited space that does not allow them to perform the natural behaviors that are key to their well-being.
According to studies, dogs that live in the wild feed mainly on leftover human food or carrion. And they spend between 10 and 22% of their active time searching for food using smell. However, pet dogs often have fewer opportunities to explore their environment, which can compromise their well-being.
Two researchers, Charlotte Duranton and Alexandra Horowitz, have shown that it is possible to improve a dog’s mood by playing a simple olfactory game with them. All that is required is a little prior training, five minutes a day, some boxes without lids, and the dog’s favorite treat.
The researcher carried out the study with 20 dogs of different breeds that they divided into two equal groups. In the first group, the dogs and their owners received training so that they could play the olfactory game at home. During the first class, the researchers showed the dog a box containing a treat and placed it one meter from the dog. Then the owner, via a command such as “go get it,” had to encourage the dog to take the treat. This is level 1 in training.
After three repetitions, the researchers went to level two. The procedure was the same, except that two empty boxes were added and the position of the box with the treat was changed in each exercise. Every time the dogs found the treat, they received praise and more treats. The owners had to practice this exercise at home with their pet for a week.
At the end of the first round of training, a second class was held. The researchers started from level two, letting the dog find the treat among the three boxes. After two iterations, they moved on to level three, which consisted of placing the boxes in more complex places, such as on top of chairs or farther from each other. In this way, the dog had to more actively search to find the hiding place. When the dog found the treat three times, the class was over.
Five minutes of play
For two consecutive weeks, the owners performed a five-minute daily session of this olfactory game with their dogs. They were asked to record the entire exercise so that the researchers could ensure that it was done correctly.
The other half of the dogs were in the control group. In this case, the owners played a different game that did not require the use of smell. In this way, the researchers ensured that both groups of dogs did physical activity, received treats and spent time with their owners.
The researchers asked the following question: Were there differences in mood improvement between the two groups of dogs? While humans can use language to express their feelings, dogs cannot describe their experiences in words. To get around this, the scientists have had to find a way to measure animals’ emotional state.
Emotions are known to influence cognitive processes such as attention, memory, or the way in which we judge a stimulus. Individuals with a positive emotional state are more optimistic and pay more attention to favorable stimuli. Conversely, those who experience negative emotions are more attentive to threatening stimuli and make more pessimistic judgments about future events.
In 2009, scientists realized that they could use these cognitive biases to assess animal welfare, and they designed a test. In general, this consisted of training the animals to discriminate between two stimuli: one associated with a positive event, such as a bowl of food, and another associated with a negative event, such as a bowl of rotten food. The animals learned to approach positive stimuli and ignore negative ones. Next, an ambiguous stimulus was presented and the animal’s behavior was observed. The speed with which it approached the ambiguous cue provided insight into whether the animal was in a positive or negative emotional state.
Several studies have validated this test as an effective tool to determine the emotional states of captive animals. In the aforementioned dog study, all the animals were tested for cognitive bias, both before and after the weeks of play. The dogs that played the olfactory game had a much more positive emotional state than the control group. The conclusion is clear: just as vacations with friends are good for people, dogs benefit from spending time every day sniffing.
Sign up for our weekly newsletter to get more English-language news coverage from EL PAÍS USA Edition