Sci­en­tists from the Uni­ver­si­ty of British Colum­bia have been fol­low­ing the old­est ani­mals alive in unex­pect­ed places. Green­land sharks (Som­nio­sus micro­cephalus) are believed to live sev­er­al hun­dred years, and can reach sizes of sev­er­al meters.

While they are usu­al­ly found in cold, Arc­tic waters, the pop­u­la­tion that the GEERG has been fol­low­ing returns to the Saint Lawrence Riv­er every sum­mer, dis­ap­pear­ing as cold weath­er sets in.

Researcher Chris Har­vey-Clark says that “all the papers pub­lished on the species, includ­ing mag­a­zine arti­cles, can bare­ly fill two shoe­box­es,” in part because of the species pref­er­ence for deep, dark and cold waters. Why they con­gre­gate in the river’s mouth is unclear.

They are con­sid­ered scav­engers, favor­ing seal car­cass­es or pieces of dead whales, though one shark was found with an entire cari­bou in its stom­ach. There does­n’t seem to be enough food in the riv­er to feed a large pop­u­la­tion of large car­ni­vores, and the sharks were not known from those waters a few years ago.

I’ve said before that one of the great chal­lenges fac­ing sci­ence today is gath­er­ing basic infor­ma­tion about the diver­si­ty of life on earth. That large sharks could sud­den­ly appear in a heav­i­ly traf­ficked water­way, then dis­ap­pear as sud­den­ly to points unknown is a sign of how lit­tle we know about the most vis­i­ble parts of the nat­ur­al world. 

At least we know what we want to learn about these sharks. For each such species that we know we should study more there are hun­dreds that we don’t even know exists, let alone any­thing at all about how it lives and where it goes. 

Over­fish­ing near­ly erad­i­cat­ed Green­land sharks, which were processed to derive vit­a­min A long ago. Had that hap­pened, these mys­ter­ies and their solu­tions would have van­ished too. We don’t know what is being lost in the rain­forests that are being cleared and burned, nor in rivers choked with pol­lu­tion. There are Fri­day Finds all around us, and there will only be few­er if we aren’t careful.