As is often the case in species where males compete to mate with as many females as possible, northern elephant seal males are much larger than females (1,800 kg versus 650 kg on average). Competitions can be battles, but more often involve mock threats and loud vocalizations. Learn more about the Mirounga angustirostris, more commonly known as a Northern Elephant Seal, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.