in fact a large living creature.
it is interesting and telling that there is not more footage showing what this object does next; it actually seems to moving to the right while the camera shifts to the right, loses it a bit, and then back a bit to the left. the photographer has a clear view of the area, and the object is right under the surface; now this short clip is suspect to me. if the object had kept moving under the surface of the water, or dove and just disappeared while the film had kept rolling focused on it we could hopefully determine that the object is single living 