Another thread ranks some species by number of individuals but ranking by total biomass also may be interesting.
(Focusing on number of individuals leads to the scary thought that each of us has 100 trillion bacteria aboard, a number so large(*) it seems like a misprint :smack: )
Wikipedia gives a start. The blue whale (Balaenoptera musculus) had total mass of over 700 million humans in pre-whaling days, so must have been near the top of mammal species, as ordered by biomass. I was not surprised to see Bos primigenius (aka Beef hamburgerus) first among mammals today with Homo sapiens 2nd. Antarctic krill (Euphausia superba) seems to be in first place among animals, but I guess ants or copepods would rank higher if one based the ranks on a higher taxonomic grade than species.
The topic seems interesting; I almost posted in GQ (“Where I can learn more?”). The Wiki article links to a book World atlas of biodiversity which I may add to my Christmas wish list!
(* - yet human-based bacteria are less than 0.1% of the “several octillion” total individuals on the planet, which number may be dominated by the marine cyanobacteria (Prochlorococcus)
Factoids like these are of no possible use to me, but have intrigued me for decades. Is this OCD, or some form of autism?