Turns out your dog (or your neighbor's dog) isn't the only animal interested in pre-digested yum-yums. Scientists rooting around in mammoth poo discovered the extinct woolly beasts used to munch their own leavings.
Or more accurately, a team led by Bas van Geel of the University of Amsterdam found fungus spores deep inside a piece of mammoth dung that can only grow on the outside of dung. Only way that can happen is if the mammoth eats the fungus, which means eating poo. Their work is in press in the journal Quaternary Science Reviews.
This is the second time evidence has been found that mammoths enjoyed poo-snacks - "coprophagy" to scientists - the first was in 2006. In some ways it's even more important than the first discovery, though, because it means the initial finding wasn't a fluke: mammoths made a habit of eating their own excrement.
The "why" is where things get interesting. Were they eating it out of desperation, or just to maintain a healthy, balanced diet? They could have been starving after a rough winter on the arid steppe climate of northwestern Alaska 12,000 years ago. Maybe leftover mammoth pie was the only thing worth eating before spring grasses came back?
Hard to say. Microbes that feasted on poo left behind high concentrations of vitamin K, B12, and B7, making mammoth pies a great way to get essential nutrients. That would've gone double for any time when food was scarce and/or the animals were stressed and in need of a prehistoric PowerBar.
But it may just have been a natural part of healthy mammoths' diets. The researchers write:
The indication that the adult mammoth had eaten feces (its own or that of another's) is interesting, but not remarkably strange. Young elephants eat the feces of their mother to obtain the necessary bacteria for the proper digestion of the vegetation found on the savanna. This behavior may have a marked effect upon the type and function of the intestinal flora. Coprophagy is an important means of making a variety of nutrients synthesized by intestinal microflora available to animals. Fermentation products that are synthesized in the intestinal tract may not be adsorbed at their site of formation and the animal might, therefore, be dependent upon the recycling of feces in order to utilize these products.
So yeah, it sounds utterly gross to us, but plenty of animals benefit from a culinary recycling program. Some of them even need it to survive.
And while most domesticated dogs should be well provided for without munching their own tootsie rolls, it may be that a small portion of their primordial brains are telling them that the endless supply of kibble can't last forever.
Image: Quaternary Science Reviews