You hear that crunching, cracking noise? That's the marrow adders. They're all around us. Tiny, timid, pretty much harmless. If you break open one of the larger bones left behind by the bonegrass you'll probably find a marrow adder peeking out at you like you've done something wrong.

What? You don't believe me? Well, I'm telling you that crackling noise ain't the campfire.

Marrow adders are tiny, inoffensive, nocturnal snakes. They measure 15cm (at most) from nose to tail when adult, and with heads that barely graze 5mm wide. Their primary food (as you might guess from the name) is bone marrow, which they suck out of the skeletons of creatures unfortunate enough to die in the bonegrass fields, after they've been stripped by numerous other scavengers. They also like to use the bones to hide in, as they're camouflaged and patterned to match bone. More than that, they like to hide inside larger bones, both as protection from the daylight and a good place to hide from any predators.

The question is whether such a small snake would be able to crack, break or corrode it's way into a bone in such a way that it doesn't end up expending more energy than it can hope to get from the marrow inside, and can still get protection from the hard bone itself.

  • 8
    $\begingroup$ I think at this point I'll introduce Osedax to the readers $\endgroup$
    – Separatrix
    Commented Mar 23, 2016 at 11:09
  • $\begingroup$ That's pretty awesome. In fact that's awesome enough that it could be expanded into a full answer with very little effort. I absolutely did not think to look at marine worms. $\endgroup$
    – Joe Bloggs
    Commented Mar 23, 2016 at 11:19
  • 4
    $\begingroup$ Possible addition: Bone snails. A little bit like a Hermit Crab that moves into bones that have been hollowed out by your snakes then drag the bone around with them like a shell. Creepy image: you go to sleep with no bones nearby, wake up surrounded by a graveyard worth of bones as the snails have moved. $\endgroup$
    – Murphy
    Commented Mar 23, 2016 at 13:05
  • 1
    $\begingroup$ Mental note: if @JoeBloggs ever builds a world, don't go there. It's a dangerous place. :P $\endgroup$
    – fgysin
    Commented Mar 23, 2016 at 15:05
  • $\begingroup$ @fgysin: Even when I try to help I accidentally end up destroying the world/building a dystopian hellscape! $\endgroup$
    – Joe Bloggs
    Commented Mar 23, 2016 at 15:18

3 Answers 3


One problem with this theory is that large predators tend to crack the bones open for the marrow inside anyway. However lets say there is a supply of food available.

It seems your snakes are actually already a good shape for this, being long and thin. You would probably better off making them more like worms than snakes at all, so that they can squeeze through tiny holes.

This would then allow them to search the bones for existing flaws in order to access the food inside. If that fails a specially adapted mouth would allow them to drill their way through the bone to get to the marrow.

You should look at marine worms. In particular as was said in the comments Osedax. They use acid to eat through the bone and then send roots inside to consume the nutrients. Your snakes could do the same or could actually move in through the hole they make. Either would work fine although being outside the bone would leave them vulnerable to predators.

  • 2
    $\begingroup$ The idea is that no large predators or scavengers exist in the bonegrass fields (at least not for long), so there's more room for exploring really niche species. That's why I keep asking questions along this vein; it's really rich creature-design terrain. $\endgroup$
    – Joe Bloggs
    Commented Mar 23, 2016 at 13:04
  • $\begingroup$ the only way to get no large predators if for there to be no large herbivores to supply the bones. $\endgroup$
    – John
    Commented Mar 15, 2017 at 17:11

Imagine this cute little fella gnawing on your finger:

Leptotyphlops Carlae

In best puppy talk voice: "Who's a cute wittle snake? You are!"

returns to normal voice " ...Wait... What? He does what?? He's trying to do what to my finger!?!?!? Ohmygodohmygodohmygod"

I would point out that the bone marrow probably wouldn't be the only thing marrow adders would eat. A bone would be a great hiding spot to snatch up larvae, worms, or the huge numbers of insects that would surely thrive in a field of dead bodies.

But bone marrow is nutritious enough that it is the Lammergeier's main food source. It should be a plausible food source for mama marrow adder and her young, so how do we get her in? The Osedax burrows into bone with acid secretions, and the Lammergeier has a highly acidic stomach to deal with the bone shards it eats, so acid seems like a good candidate. Maybe mamma adder can also regurgitate some collagenase to speed the decomposition of the hard bone exterior. She can still have a sharp burrowing beak to scrape the softer dissolved bone away. Knowing what vinegar does to chicken bones overnight, I think it is entirely plausible that she could burrow her way into a bone with stronger stomach acids and enzymes in a reasonable amount of time.


If the snakes are really tiny and the bones are from large creatures such as sheep or dogs, then they can squeeze into them by using the holes for arteries & veins. Wikipedia article on nutrient foramen

If the snakes are a bit bigger, then gnawing or digesting bone is well worth it: bones are calcium phosphate. Phosphorus is a vital ingredient in biology - the snakes won't just be make their own skeletons out of it, they'll also be making their nervous system (lots of phospho-lipids), fueling their cellular metabolism with it ATP, constructing DNA with it (phosphate group), packing it into their egg yolks to make their babies, and so on. That's why farmers put phosphate fertilizers on their fields - the growth of living things is often limited by the amount of phosphate available to them.

So a fresh bone, packed with fat (bone marrow) and phosphate is a real prize. There will be little snakey punch ups over who gets to claim it. Mama snakes will be all over it like a rash, since it will supply both the lipid and the phospho bits of the phospho-lipids her babies will build their brains and nerves from.

Even a dry bone can be a prize for its mineral content. It will be the snake equivalent of a 'salt lick'.


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