They’re fucking. Ice Elementals.
So it’s very likely they diverged from other Sleeper Shark lineages during one of the Pleistocene ice ages, when thickening polar ice would have trapped certain populations in perpetual icy darkness for thousands of years. These are the descendants of the survivors of that.
Their flesh is toxic for numerous biomechanical reasons that directly relate to their ability to not only survive but thrive in waters that would literally freeze you or I solid.
Urea and Trimethylamine-N-Oxide
The Greenland shark accomplishes this using first concentrated Urea, which is a natural antifreeze and depresses the freezing point of the shark’s fluids; and TMAO, which stabilizes proteins against denaturation, both from the concentrated Urea and the crushing pressure of the deep.
Additionally, the Greenland Shark has 3 distinct Hemoglobin complexes in its blood, 2 of which are apparently specifically adapted to be unaffected by the high antifreeze concentrations. More research is needed here.
{anecdotally; once pulled from the water by fishermen, the shark allegedly persists thrashing and fighting for far longer than any other fish, and there are stories of the flesh itself continuing to twitch and move long after its apparent death, as the creature is butchered}
Their longevity is partially enabled by a highly derived genome: it is comprised largely of transposable elements, also known as “jumping genes,” which normally cause organisms to be more prone to Cancers, but, are also capable of self-replication; and amongst these, we have already identified over 80 discrete gene sequences dedicated specifically to DNA repair.
They’re viviparous, and the female reproductive systems are quite complex, including a system of villi to deliver oxygen to the developing pups. The variability in gestation time remains subject of ongoing study: how is this accomplished? What triggers it? Many questions; fewer answers.
Truly a remarkable and magical Beast of the lightless depths. It is an honor and a privilege to share this wet rock with you all 🫡
