Is killing a dog worse than killing a pig?

I read an article yesterday (on one of the major Czech news servers) about a man who threw his mother’s dog through a stairwell (it was the form of staircase where there’s a hole in the middle) from the 11th floor as a form of revenge to his mother. I opened the comments section (which is not a good idea on a news server anyway) because I was interested in how people reacted to this despicable deed. The opinions were virtually unanimous: “how can anyone possibly do that to a dog?”, “poor dog!”, “he should have been thrown down right after the dog!”

I can only speculate what the comments would be should the poor animal be a pig instead of a dog. I fancy, considering the Czech nature, that the top comment would resemble something like “He was probably experimenting with new ways of making minced meat.” So why if a completely nice dog is killed, people are outraged and ashamed that anyone could possibly do that, and if a completely nice pig is killed, people make comments about bacon?

Pigs are on par with dogs in terms of intelligence

Or should I rather write “on birdie with”? Pigs are actually very smart. There was an experiment^[1] in which two groups of pigs were (independently) positioned so that they could not see a bowl with food directly but only as a reflection in a mirror. For the pigs in the first group, this was the first time they had seen a mirror, and 9 out of 11 of them went to the mirror and searched for the food around it. The 8 pigs in the second group, however, were placed in a pen that contained a mirror (but no food bowl) 5 hours prior to the experiment which allowed them to get used to how mirrors work. During the experiment, 7 out of 8 of them didn’t go to the mirror; they went to the location of the food which they deduced from the reflection instead.

Tasks such as this one prove that pigs are capable advanced ways of thinking. There are many other proofs of their intelligence—they can associate levers they have to press with reward they get, learn to navigate through a maze and more ([2] is a review of a huge amount of studies of pigs’ intelligence). But all this is achievable by mechanical learning; no “human-like” qualities are needed. We all know that dogs can be emotional, they are happy in certain situations and sad in other. But pigs don’t have emotions, do they?

Pigs have emotions, too

Of course pigs exhibit primitive emotions typical for most mammals, such as a sow taking care of her piglets, or piglets being stressed when taken away from their mother. However, there was also a sophisticated study^[3] to asses more complicated emotions in pigs, namely being optimistic or pessimistic. The study was designed as follows: Pigs were taught to associate one particular sound with a positive event (being given food) and another sound with a negative event (being startled). Then, they were placed into different pens, one large with interactive toys and straw and the other one barren. Then, a neutral sound vaguely resembling both of the learned sounds was played.

Interestingly enough, almost all pigs being in the comfortable pen associated the sound with the pleasant outcome (and approached to get a treat) while virtually no pigs in the uncomfortable one did, fearing something negative would happen (and the same happened when the two groups were reversed). This is the typical behaviour we can observe in humans—if a human is in a good (optimistic) mood, he or she tends to view a neutral event as leading to a positive outcome, whereas a person in a bad (pessimistic) mood has an opposite tendency (as in the typical half-empty/half-full glass example).

Pigs are not dirty

There’s a common misconception that pigs are dirty animals. That they are sweaty (who would like to sweat like a pig) and spend their lives lying in mud. First of all, the notion of cleanliness is completely artificial. I can quite easily envision extraterrestrials coming to Earth thinking “Eww, humans cover their bodies with water every day. So disgusting!” A dung beetle is not dirty just because he touches a ball made out of feces. It’s a healthy thing to do for him. So even if pigs were “dirty”, it wouldn’t really mean anything.

However, pigs are cleaner then most people think. If they are allowed to do so, they keep their “toilets” (places where they urinate and defecate) far away from their “homes”. And to sweat like a pig would be actually a good thing—because they are almost incapable of sweating. And that’s the reason they like to lie in mud; it’s the natural way for them to cool down and to protect themselves from sunburns.

Conclusion

Pigs’ physiology and their ability to feel pain is very similar to that of humans (to the extent that, for example, pig skin is used in certain cases as a transplant for humans). Recent studies have not only shown that pigs are very intelligent animals whose intelligence is comparable to dogs, chimpanzees and other highly developed species, but also that pigs are capable of sophisticated emotions. Would we agree with hundreds of millions of dogs being closed in a small pen for the most of their life and then painfully slaughtered and processed to sausages? I don’t think so. So why do we, as a society, agree with more than a quarter of a billion pigs being slaughtered each year, although their intelligence level, capability of feeling pain, and emotional world is as rich as that of dogs?