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Sheep are not stupid

Dr. Else Verbeek
Dr. Else Verbeek

Dog behaviour scientist and consultant.

As a scientist working with sheep, one of the most frustrating (and unfortunately one of the most common) comments I hear is: sheep are stupid!
 
In my first blog post I will explain why this is a stupid assumption.
 
One of the most prestigious scientific journals “Nature” published a paper that showed that sheep are able to recognize 50 different sheep faces and remember them for over two years. Sheep have similar brain systems as humans for face recognition. Face recognition is important for many species (including humans), as it is a building block for social relationships. Other research has also shown that sheep can recognize several human faces.

 

I had a funny experience with this recently. When I was walking across our research farm, one of the farm staff was just moving a group of sheep to a new paddock. All of a sudden, a few sheep separated from the flock and walked towards me.

It turned out these were some sheep that I used in an experiment about 6 months ago! I was amazed how quickly they recognized me, and I have to admit that I didn’t recognize them until they approached me for a cuddle and some food! Sheep will remember you when you treat them right and will come to greet you when they see you, even after several months!

Sheep have an amazing spatial ability to find and remember places. In one experiment, sheep were trained to find food patches in a paddock. Each patch was also associated with a cue. Once the sheep had learned where the patches were located, the food patches and cues were moved. Sheep first went to the locations were the food patches were previously located, but when they found no food, they looked for the cues and found their food in the new place!
 
Sheep are able to feel pain and distress. Research has shown many times that sheep being castrated or tail docked without the use of local anaesthesia express a range of distress behaviours, such as increased vocalizations and activity. These are behaviours that you would also expect from a human in pain! 
 
Furthermore, a hormone called cortisol (an indicator of physiological stress) is also increased when sheep feel pain. The use of a local anaesthetic reduces both behavioural and physiological signs of distress. Unfortunately, local anaesthetics are still not used on all farms in Australia and New Zealand…
 
Sheep will become pessimistic when they are kept in an impoverished and unpredictable environment. Just like humans, sheep that are constantly stressed will eventually become pessimists, in particular when they cannot predict the stressors or control them. Psychological tests applied to chronically stressed sheep show that they have a pessimistic outlook on life, or in other words, they see the glass as half empty rather than half full. It is amazing that our knowledge of animal emotions has advanced so far that we can now tell when sheep are pessimistic or optimistic. In the following weeks I will explain exactly how we assess this in animals!
 
Sheep are able to experience hunger. My PhD research was dedicated to studying the perception of hunger in sheep. I have shown that acute and chronically undernourished sheep are willing to “pay a high price” for food. Of course “the price” of food was not a monetary one (I guess that even though sheep are smart, they wouldn’t understand the value of money), but a distance walked. By changing the “price” of food (the distance walked) I have shown that sheep are willing to walk many km for just a 5 g reward. The more hungry the sheep, the further it is willing to walk. This shows that sheep are able to make decisions based on how they feel.
 
Sheep are able to experience positive emotions. When sheep are given nice food or when they are (voluntarily) groomed by a handler, their heart rate variability and ear postures change compared to sheep that are left alone or are stressed.  It has even been shown that voluntary grooming changes the activity in brain structures associated with emotions. We have only just started to discover the existence of positive emotions in sheep and I will keep you up to date with new developments.
 
I think it is now pretty clear that sheep are not stupid! They have amazing spatial abilities and can recognize many sheep and human faces. Unfortunately many people still don’t acknowledge that sheep have feelings, but I hope that more research on sheep emotions will soon change this!

Further reading and references:
Sheep face recognition:
http://www.nature.com/nature/journal/v414/n6860/abs/414165a0.html