The term 'ONE OF THE LARGEST LAND MAMMALS' can be solved by the five letter word 'HIPPO'. Hippos are large, semi-aquatic mammals native to sub-Saharan Africa. They are the third largest land mammal after elephants and rhinos, and can weigh up to 4, 500 pounds. Hippos are herbivores and spend most of their time in water or mud, emerging at night to graze on grass. They are considered to be one of the most dangerous animals in Africa due to their aggressive nature.