 During the 16th century , <unk> was named " River de <unk> " by Portuguese <unk> . There are several legends surrounding the name <unk> . During the Brooke dynasty , the indigenous <unk> people practised <unk> to maintain their social status in the community . They threw the heads into the <unk> River , after which the heads had to be collected from the river . The practice of collecting the heads was known as " <unk> <unk> " ( picking heads ) in the local native language . Another story relates that two <unk> warriors named <unk> and <unk> built houses along the river . They and their followers frequently carried out preservation of severed heads near a small river stream branching off from <unk> River because the river bank was flat and wide . Therefore , the small river stream was named " <unk> <unk> " river . <unk> who came to <unk> subsequently pronounced the name as " <unk> " , and later the name evolved into " <unk> " and , finally , " <unk> " . 
