Bones are central to our survival: the skeleton of a vertebrate is what keeps it upright and supports it against gravity. But they are also essential for some animals in a more surprising way: when an animal dies, or a deer sheds its bony antlers, all that calcium and bone marrow is a tempting meal for creatures of a range of sizes, including the tiniest.
A field mouse is a very tiny thing, easily caught by any number of altogether larger creatures. This one was caught by a Mackinnon’s Fiscal Shrike in Kenya:
and this one was eaten, and its soft tissues digested, by a coyote (or fox) in Maine, leaving the skeleton substantially intact, including even the tail :
(It didn’t digest the fur either, and once time and rain have cleared away the residue, fur and bones are made visible.)
These tiny creatures eat small seeds, like these beech nuts:
and during the long winters in Maine they emerge from their impossibly small holes, risking life and limb, to forage:
An unlikely food source is a shed deer antler. In Maine bucks grow their bony antlers in March or April, and shed them the following winter. I found this one in October, by which time it had been eaten by squirrels, mice, chipmunks, raccoons, opossums, porcupines, foxes, bears, and even otters, for the 20% calcium, 10% phosphorus and mineral salts content.
The outside is compacted bone, very hard, but rodents have sharp teeth.
The size of the tooth marks is a clue to who has been eating the antler. In the picture above it was something small, squirrels or mice. If it has cracked right through to the inside, it is something bigger:
The interior is spongy bone, well supplied with blood vessels when the antlers were growing. For whatever reason, this doesn’t seem to get eaten much.
These ones (found on a different occasion, but also in the autumn) looked older, but they hadn’t been quite as thoroughly chewed:
So if you view the world through the eyes of a mouse, it has two reasons to be grateful to bones: for giving it the strength to stand and to run, and for nourishing it at the end of a hard winter.
PS Here is Robbie Burns 1785 poem “To a mouse”, a rare literary paean to this timorous beastie:
And then course there is E.B.White’s masterpiece Stuart Little.