“Don’t be late for your weekly mud bath!” – Pigs can estimate time intervals in the range of days

0We can all agree that pigs are astonishingly clever creatures. They possess excellent spatial memory skills, remembering not only multiple feeding sites but also whether they’ve visited them recently. When foraging in groups, dominant pigs often exploit the knowledge of lower ranking pigs regarding the location of food sources that the dominant pig is unaware of. Subordinate pigs have also been shown to subsequently apply ‘anti-exploitation’ strategies such as being more cautious when close to dominant group members and only moving towards food when they are out of sight or cannot see them. But do pigs actually know how much time has passed since they last visited a food source or scrounged off another pig? Remembering when you last visited your favourite acorn tree might come in handy as depleted food sources can replenish over time and are thus worth a second look in the future.

New research now sheds light on pigs’ ability to estimate such time intervals. To do this, the researchers conducted two experiments; one focusing on estimating intervals of a few minutes, while the second one focused on intervals of several days. In the minute-experiment, pigs were equipped with a heart rate monitor device and could feed freely at a trough. During a training phase, they learned to expect an interruption while feeding at a trough after a fixed interval of a few minutes. In the actual test, this interruption was delayed and the researchers observed how the pigs reacted around the time the initial interruption would have occurred. Heart rate measurements and behavioural indicators, such as head lifts and food stamps, showed that the pigs became continuously more aroused towards the end of the interval. However, they did not show a sharp reaction at the moment the interruption would have occurred, and actually showed the greatest reaction some seconds after the disturbance would have been expected. Due to this, instead of estimating the time interval, it’s possible the pigs were simply following a rule of thumb such as monitoring their level of satiety or the amount of food they had already eaten.


Experiment 1: Pig with heart rate monitor device feeding at a trough (taken from Fuhrer & Gygax 2017)

In the day-experiment, the pigs were introduced individually to a test pen from which they could choose to enter two additional pens. The pigs needed to learn that a low-quality reward was offered in one pen every other day and a high-quality reward in the other pen every fifth day. After intense training, pigs were increasingly more likely to open the door leading to the high-quality reward on the correct (5th) day, but not so on days in which entering the pen wouldn’t have yielded a reward. The authors concluded that their pigs could estimate time intervals in the range of days, but had problems estimating time intervals in the range of minutes. These results complement a previous study, which showed that mini pigs demonstrate episodic-like memory skills, i.e. they remember not only what happened at which location, but also when a specific event happened in temporal comparison to another event.


Experiment 2: Pig entering one of two pens with a food reward in it (taken from Fuhrer & Gygax 2017)

To remember and recall previous events and estimate time intervals has a major impact on an individual’s capacity for suffering and thus is of interest to researchers aiming to improve animal welfare. For instance, if an animal perceives the length of time during which it remains in a negative situation, its suffering could be inflated. This effect could be even further exacerbated if animals can remember and foresee such events. But the ability to estimate time intervals could also be used to counter negative conditions by signalling their duration to the animal via, for example, acoustic cues. The ability to estimate such time intervals could, therefore, result in both welfare benefits and problems.


The current finding that pigs are able to estimate time intervals adds to a body of fast growing literature on the cognitive capacities of pigs. In fact, these findings are desperately needed, as it is of great importance to know how pigs, and farm animals in general, perceive their environment in order to adapt husbandry and management conditions to their needs. So remember: the next time you arrange a meeting with your favourite pig at the petting zoo, be aware that it expects you to be on time.


“Here’s looking at you, kid!” – Goats know when they’re in the spotlight

Imagine yourself in a new city, without a map or smartphone. You are desperately searching for your hotel when you see two people in front of you. One of them is already looking at you, while the other one is reading the newspaper. Which of them are you going to ask for directions? Intuition says you should choose the one already watching you, right? – they’d give a faster answer.

Behavioural experiments on primates and dogs have shown that they are sensitive to differences in human attentional stance as well. For example, when dogs are told not to eat a reward placed in front of them, they disobeyed more quickly when the human who gave the command was looking away or was distracted playing a Gameboy. When rhesus monkeys had a chance to steal a piece of fruit from one of two researchers, they preferred to steal from the researcher who was looking away or had their eyes closed. Sounds all too familiar, doesn’t it? Of course, we know that apes, monkeys, and our dogs are pretty clever, but what about our barnyard buddies? How well do farm animals guide their behaviour on rather subtle human body cues? Only a few experiments have addressed this issue so far. One example showed that sheep react differently depending on whether a person is staring at them or not. They moved more and looked more often at the person when the experimenter was looking at them – indicating that they might perceive it as a warning sign. In addition, pigs have been found to approach an attentive rather than an inattentive person when being trained to receive food from humans.

We previously found that goats alter their behaviour depending on the body and head orientation of a human sitting in front of them, using a so-called food-anticipating paradigm. In this experimental setup, a researcher remained for 30 seconds in an assigned posture before providing the goat with a reward. Goats showed the highest anticipation for the reward when the researcher was clearly paying attention to them (see video here)fbn. However, anticipation of the reward dropped dramatically when less attention was paid to the goat. In addition to their anticipatory behaviour, we recognized a different, very prominent, behavioural pattern – goats at some point started to ‘stare’ at the researcher (see video here). Curiously, this behaviour was highest when the researcher was present but was not paying attention to the goat. Again, this might seem oddly familiar to some of you. However, we couldn’t rule out that subjects had learned during prior training that a certain posture of the experimenter would result in a reward. Therefore, we aimed to validate our findings using a slightly different test setup.

In our new goat research, we investigated whether goats are sensitive to a human’s attentive stance in a more naturalistic and cooperative setting. In a series of three experiments, goats had the opportunity to approach one or two experimenters in anticipation of getting a food reward (a piece of pasta). In our first experiment, we found that goats, when confronted with a human who had his back turned to them, actively go around the experimenter to enter the zone of attention. However, this was only the case for full body orientation and not head orientation alone. In our second experiment, goats had the opportunity to choose between two experimenters, with one paying attention while the other one was looking away. Goats preferred to approach humans that oriented their body and head towards the subject, whereas, again, head orientation alone had no effect on goats’ choice behaviour. In a final experiment, goats were transferred to a separate test arena and were rewarded for approaching two experimenters providing a food reward during training trials. In the subsequent test, goats had to choose between the two experimenters differing in their attentional states. And again, goats did not show a preference for the attentive person when the inattentive person turned her head away from the subject. However, surprisingly, goats preferred to approach the attentive person compared to a person who closed their eyes.


The different test conditions in the choice task: A) Head away B) Eyes closed C) Covered head D) Covered eyes. Goats preferred to approach the attentive experimenter in B and C, but not A and D.

Together with previous findings, these results show that goats are extremely sensitive to the body orientation of humans, and even try to get into the spotlight if a human turns away from them. However, and contrary to our previous work, we did not find evidence that they take human head orientation into account. We argue that due to goats’ laterally positioned eyes, they might not consider a human with his/her head turned to the side as genuinely inattentive, because a goat with the same head orientation would still be able to catch up on everything that’s going on. So, next time you walk past a goat farm and want to observe what they are up to, just be aware, they probably already know you’re watching them!




Goat see, goat do? – Social learning in goats

p1090715Anyone who has interacted with a goat knows that they are full of character. Now even scientists know they are smart cookies – they can solve puzzles and remember the solution for months. They think in categories. And when confronted with a problem they cannot solve, they try to seek assistance from humans the same way dogs do.

However, in these tasks, the goats had to solve problems by themselves. So what about their ability to learn from others? When a mother goat strolls away, her kids will follow. Kids also learn whether things are edible or not by observing their mum primarily because foraging skills are extremely important. But what happens once the kids grow up? Are they able to learn from other goats or even humans? This topic has proved controversial in horses, with evidence pointing in both directions. For example, horses that observed another horse manipulating an apparatus to get food also spent more time near that test apparatus. However, observer horses were not faster getting the food at all.

p1090697The controversy becomes even worse for goats, with no indication of social learning in adults. So we don’t know yet whether they can learn from their friends, regardless of whether their buddies are other goats or humans. But what could explain this lack of evidence for social learning in goats and ungulates in general? Perhaps the fact that most ungulates live the lives of grazers and browsers – having food distributed literally below their mouth, making it unnecessary to learn from others. But what about that sweet spot of grass that my neighbour might know about but I don’t? Despite the overflow of food, wouldn’t it still be helpful to follow my pals when they walk off full of motivation? Additionally, is a test that requires you to manipulate an object with your mouth of any ecological relevance if you are a goat or horse? Yet another explanation for not following (often more dominant) demonstrator goats might be that you just avoid being attacked while competing for food.

Keeping these potential shortcomings in mind, we tried to use another, simpler experimental approach. We assessed social learning in goats using a so-called detour task, in which food was placed behind a V-shaped obstacle. Detour tasks are an excellent paradigm to investigate both spatial, and social problem-solving in non-human animals. A reward (in the case of goats, a small piece of dry pasta) is placed behind the barrier and in order to gain the reward, the tested goats had to detour the obstacle. Sounds pretty simple, doesn’t it? However, solving this task has been proven to be very difficult for many animal species because they have to actively increase their distance from the reward in order to access it. So what we did was test goats in this task: One group received no demonstration from a human and had to solve the task alone. However, another group saw a human detouring the obstacle and placing the reward behind it before they had to solve the task.


We found that a single presentation by a human solving the detour resulted in goats being able to solve the task faster compared to the group that did not see a demonstration. Furthermore, nearly all subjects that received a demonstration used the same route as the demonstrator in the subsequent test. Thus, goats picked up some information from the human demonstrator during this task. Our next steps will be to determine which kind of information they are exactly paying attention to.

Our findings show that animals that have been primarily domesticated for food production are capable of perceiving information from humans, in a similar manner to companion animals such as dogs. This kind of research will not only help raise awareness for the complex inner mental lives of farm animals but will also improve the welfare of millions of livestock animals in the long term.