There is an old adage that ‘you are what you eat’, and in many ways, this is true.

We all know that eating healthy – think fruits, vegetables and wholegrains – can give everything from our energy, our immune system, and even our memories a boost, whilst refined sugars, processed meats and saturated fats make us sluggish and risk our health too.

Of course, the same is true across the animal kingdom too, with the food an animal consumes directly affecting its health and quality of life.

And according to a paper recently published in the Journal of Archaeological Science, the diet of sled dogs thousands of years ago had just the same impact on their own lives.

To truly understand the lives of prehistoric sled dogs, who lived and performed their duties in the sub-zero Siberian Arctic, the research team turned to the excrement of the dogs, which had been literally frozen in time for 9,000 years.

And what they found in the poop was something quite astonishing.

Firstly, it seems that the sled dogs were riddled with worms. An examination of the worms and their eggs found two distinct types: Dibothriocephalus tapeworms, which suggested that the dogs ate undercooked (or, potentially, uncooked) fish, and Taeniidae worm eggs.

The latter came from reindeer meat – but the idea that these dogs ate reindeer was by far the most surprising thing that the researchers discovered.

In amongst the droppings, the researchers found traces of polar bear fur – a finding that is backed up by dog teeth marks on polar bear bones that have previously been discovered in the region.

Of course, polar bears were prevelant in the region, but it is thought that they were primarily killed to feed the hunters that the sled dogs worked for.

So we return to ‘you are what you eat’ and, of course, the sled dogs weren’t literally polar bears. But just like the rest of us, these sled dogs were hugely impacted by their diet.

It wasn’t just the worms, which undoubtedly affected their performance – the truth is, these dogs were likely hindered by the meat of the giant predators, since their bodily function is more suited to the blubbery animals that they would naturally hunt – think seals and walruses – meaning that the sled dogs were less effective at their jobs, thanks to the unsuitable diet they consumed.

If you think that’s impressive, check out this story about a “goldmine” of lithium that was found in the U.S. that could completely change the EV battery game.