A Dog’s Dinner

Banana Joe stole the show!

No, not the LA radio presenter, I mean the affenpinscher from Attleboro who won Best in Show last week at the Westminster Dog Show in NYC.

I’m not a pooch person, prefer big mushy dogs, but Joe the affenpischer who looks like a cross between a toy and a monkey is easy to love. And a monkey dog he is (ein Affe, a monkey). Like monkeys, Joe and our Golden enjoy a banana, which is not so surprising if you consider it is a perfectly natural food for their cousins – wolf packs in Minnesota and Alaska.  Erhh!

We changed their dietary preferences after the first wolf cub was adopted by a human family.  I ought to pause to correct myself because dogs can’t express preferences any more than I could as a London schoolboy. It is only a slight exaggeration to say that we were served Dickensian gruel for school lunch. I remember peering through the kitchen window at the cooks watching over steaming vats of bubble and squeak made from yesterday’s left-overs and stirring custard thick as tar but not so smooth. It was ‘Hobson’s choice’, or, in other words, no choice at all, just as it has always been for our dogs.

Until the food industry realized there was a canine market, most dogs had to make-do with human left-overs, living hopefully for a bone flung their way with a morsel of meat on it.  As members of the Order Carnivora, their ancestors enjoyed a high protein diet before they were domesticated around 10,000 years ago (some put it earlier). Neolithic people were then switching from hunting and gathering to agriculture, growing various cereal crops in the Old World, sweet potato, corn and beans in the New, and – yes – bananas in New Guinea.  Growing-their-own enabled them to form settlements with greater food security, and afterwards their diet became much richer in starch. So did the dogs’.

A new study of whole genome resequencing shows what an impact this change had on canine genetics. There are not as many genetic differences between dogs and wolves as you might think from their manner and appearance, but significant differences were found between genes involved in brain function and the digestion of starchy and fatty foods.  It seems that a genetic bottleneck occurred in the early prehistory of domestication. Animals with gene variants that favored compliant behavior and efficient starch digestion squeezed through, and those survivors became the founders of modern dogs. The wild-type wolf genes disappeared because dogs lacking genes that were better adapted to the new life were either kicked out for bad behavior or didn’t thrive on the new diet. Lying at your fireside is an example of how we sculpt the evolution of species.

Now to sweeter talk. Sweet is one of our five senses of tastes, but long before we celebrated it by inventing confectionary it was probably beneficial for distinguishing between good and bad food. Since wolves will occasionally eat vegetable matter it’s not surprising that they share the same sweet taste receptor gene, Tas1r2, as ourselves, and dogs inherited it from them.  Other mammals can taste sweetness too – raccoons and of course bears – but not all. Cats can’t taste it because their Tas1r2 is pseudogenized (meaning it doesn’t function), and likewise in sea lions, otters, dolphins, and hyenas.  Since they are flesh-eaters that swallow their food whole there’s no time for tasting and therefore no point in having a sweet taste receptor. But biologists who love to tell a commonsense story are often embarrassed by an ugly fact that threatens a beautiful theory. We might expect a species that sips its food to have a well-developed sense of taste, but apparently vampire bats don’t have a sweet tooth in their heads.

Now back to bananas and Banana. Our dog, Lilah, has a more discerning palate than her owner because she turns her nose up at green bananas which are just full of starch but she will happily chomp on yellow ones in which much of the starch has been converted to sugar.  We throw away overripe bananas but, given the chance, she will gorge on them knowing they have the most sugar.  The French clearly know their bananas too because their grocery stores have premium prices on fruit with brown skins.  Belle banane.

Banana Joe deserved a better reward. He was taken to a swanky Manhattan restaurant where he was served filet mignon to celebrate victory. I expect he was glad to leave starch behind for a day if only to prove he is still a card-carrying carnivore.

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