Ranitidine is a competitive, reversible inhibitor of the action of histamine at the histamine H2-receptors, including receptors on the gastric cells. Ranitidine does not lower serum Ca++ in hypercalcemic states. Ranitidine is not an anticholinergic agent.
1 The Blue Marlins have a diet of: Octopi, squid and pelagic fish such as black fin tuna and frigate mackerel.  They do prefer to hunt alone and during the day, rather than in schools, so it is safe to say they are a rather antisocial species.
CARNIVOROUS SHARKS. A carnivorous shark diet usually includes fish, mollusks, and crustaceans. Large species also consume marine mammals such as seals, dolphins, sea lions, and porpoises, as well as large fish species such as tuna, mackerel, and even smaller shark species. Some even extend their consumption to seabirds.