Bone-Eater of the Dark Depths

osedax_colorWeb_JMLandin

When a whale dies, its body often sinks to the bottom of the sea. From death comes life – an entire ecosystem blooms from the resource-rich remains.

Scavenger fish (sharks and hagfish), as well as crabs, shrimp, and octopuses, consume the flesh, leaving only a massive skeleton behind. Even the bones are devoured in this cold, dark place. Osedax worms, a.k.a. bone-eating or zombie worms, slowly dissolve and ingest the protein- and fat-rich bone. Very slowly… for up to a century. The worms grow root-like structures into the bone’s marrow. These “roots” contain symbiotic bacteria that help digest the nutrients.

Descriptions of bone-eating worms were first published just 15 years ago. Since then, more than a dozen species of bone-eating worms have been identified from every ocean. Originally, researchers thought that the worms evolved with whales but more fossil evidence indicates that Osedax were likely present on the bones of marine reptiles at least 50 million years earlier. (1)

The whale-fall ecosystem was recently captured on video (the fuzzy reddish-brown coating on the bones are large numbers of the worms).

  1. Danise, S. and N.D. Higgs. 2015. Bone-eating Osedax worms lived on Mesozoic marine reptile deadfalls. Royal Society Biology Letters. 11(4)

Penis Bones – no joke!

bacula_JMLCarnivores have ‘em. Rodents and bats have ‘em. Even many primates have ‘em. But not humans.

The baculum (penis bone) is one of the most variable bones in the mammalian skeleton – you can even ID an animal by the shape and size of that one bone. Just like with insect penises, the shapes of these reproductive structures can change quickly in evolutionary terms (Carl Zimmer writes a wonderful post looking at these shifts)
What’s its function?
Well, we’re not 100% sure yet. It may allow males to copulate before being fully, ahem, at attention. Or it may stimulate the female to ovulate. Some bacula grow spiny projections which may, like some insect penises, clear out other sperm before injecting one’s own.
Let’s not leave out the girls!

The penis and clitoris develop from the same structure. So, if the penis has a bone… does the clitoris? You bet! It’s called the os clitoridis (or baubellum).