The next time you find your beloved pet with its face in the garbage bag, don’t get angry; it’s atavism rather than avarice messing up your kitchen floor

It’s common enough to ask the question “if you were an animal, what would you be?” Psychologists of both the legitimate and the ‘round the kitchen table’ variety can, and have, read much into the various answers people give. Personally, I find it amusing that a certain sort of person identifies themselves with wolves. In general, I think these lupine-wannabes believe the wolf to be a capable, ruthless beast, exuding the kind of loner, wilderness-romantic vibe which they themselves like to think they carry off as they type up another Excel spreadsheet and email Andy from accounts.

Of course the reality is that wolves are pack animals with uneven reproduction. Most of the pack is subordinate, with many young males never getting any opportunity to reproduce. Actually, thinking about it, maybe those that identify themselves with wolves aren’t that far off the mark?

It is also a common enough question to ask whether somebody is a ‘dog person’ or a ‘cat person’ and again, much is read into the answer. Sometimes it can be difficult to decide so allow me to offer some help. Are you the sort of person that likes to have their quiet evenings constantly interrupted by a slavering hairy beast that requires constant attention, bounds around the park like a mobile s**t dispenser and, at any point, might attempt carnal relations with a door mat? Congratulations; you are a dog person (or in a relationship you might be well-advised to leave). Or, perhaps you prefer the company of something aloof that is possessed with an incessant desire to show you their ‘tea towel holder’ and a need to fill your dwelling with the dreadful stench of what exudes from the aforementioned orifice? Congratulations; you are a cat person. Or you are living with a performance artist.

For an animal near universally regarded as man’s best friend, though, it is interesting that the English language is full of negative canine associations. To be dogged by something, to be dog-tired, Churchill’s ‘black dog’ of depression, the dog watch, dogging (Google it, but not at work...) and so on. And a recent study of dog genetics might not help the matter.

As everyone knows, despite some dogs resembling little more than upholstered rats, domestic dogs originated from wolves. But exactly how and when our association with them arose remains a puzzle. By examining the genetic differences between dogs and wolves, encoded in their DNA, we can start to get some insight into how the latter became the former.

What DNA analysis has shown us is that dogs possess, on average, around seven-times more copies than wolves of the genes that encode for the enzymes that break down starch. Enzymes aren’t just about getting those stubborn biological stains (a euphemism if ever there was one) out of your laundry. They are biological molecules that act as catalysts to control the truly epic number of chemical reactions that take place constantly within our bodies. One such group of enzymes is involved with digesting the starch that is locked up in the plant matter that we eat. If you chew a piece of bread long enough you can detect one such enzyme, salivary amylase, at work. Slowly the cud you chew will get sweeter as the long starch molecules get split up into their shorter sugary building blocks. The presence of so many copies of starch-digesting enzymes in modern dogs compared to their wolf ancestors gives us a potentially valuable clue as to how the modern dog arose.

There are two competing hypotheses as to how the human-wolf (and therefore dog) association began. One is that wolves and humans formed some kind of alliance based around hunting, with early man perhaps adopting wolf cubs. The less romantic explanation is the waste-dump hypothesis. This suggests that wolves started to scavenge around our leftover food and eventually, because of the rich pickings, came to form more permanent alliances. In both cases, we then started to breed the animals for desirable qualities, such as the ability to fit in a small hand bag.

Sadly for dog-loving romantics, but realistically for anyone that has ever spent any time with a dog, the presence of all those copies of starch-digesting enzymes firmly supports the waste-dump origin. Proto-dogs were seemingly selected for their ability to succeed around our early agricultural efforts, tucking into whatever we didn’t consume. So, the next time you find your beloved pet with its face in the garbage bag, don’t get angry. It’s atavism rather than avarice that is messing up your kitchen floor.

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This article is by Adam Hart, from the November 2013 edition of Cotswold Life.

Adam Hart is Professor of Science Communication at University of Gloucestershire.

Follow him on Twitter: @AdamHartScience