Sea lions are known as the largest mammals found in New Zealand. Males are considerably bigger and heavier than females, an average sea lion grows up to 3 meters long and weighs nearly 450 kilograms. Sea lions densely populate sandy beaches of the South Island and the Auckland Islands. The best time to observe huge mammals is during their breeding season that stretches from November to January. The animals are polygamous, and perhaps owing to this fact they are also called Hooker's Sea Lions. Like fur seals, sea lions appear to be quite aggressive, yet this time not because of the fear of a threat, but through their fights for breeding locations which occur between the bulls usually in November: all the territories must be divided before the females' arrival.