How Iban known as Sea Dayak to Westerners??

The Ibans were the original inhabitants of Borneo Island just like the Dayak tribes.Dayak people real BORNEO itself(Link here)

In fact,Iban never called themselves as a SEA DAYAK. Since, they never found live near the sea or coastal area in the island of Borneo for the century.

Like the other Dayak tribes, they were originally farmers, hunters, and gatherers & found in the jungle & interior of BORNEO ..& build the settlement along the river ...........but during the reign of the Brooke’s and the British Colonial in Sarawak Borneo...the Brooke Dynasty referred them as a SEA DAYAK since they are the most dangerous tribe in Borneo and so daring in their war battle just to have the head of their enemies as their war(head) trophies.

Antu Pala (Head Trophies)
These are human skulls from the people killed by the head hunters.
The skulls are hung in Iban people long houses as their trophies of their kills.

(Iban(Sea Dayak/Dyak) Warrior in Full Regalia(CLICK here) during Photoshoot with KALUANEXPRESS .COM(Aug 2011)
at  Taman Tasik Permaisuri Cheras KL
Trying to become a FIERCE HEADHUNTER OF BORNEO just like my ancestor in ancient time

Some believe that the word Iban was an ancient original Iban word for people or man. The modern-day Iban word for people or man is mensia, a totally modified Malay loan word of the same meaning (manusia) of Sanskrit Root.

Seventeen years among Sea Dyaks of BORNEO(Link)

Iban(Sea Dayak) the most formidable headhunters on the island of Borneo. ??

The Ibans were unfortunately branded for being pioneers of headhunting. Headhunting among the Ibans is believed to have started when the lands occupied by the Ibans became over-populated. In those days, before the arrival of western civilization, intruding on lands belonging to other tribes resulted in death. Confrontation was the only way of survival.

In those days, the way of war was the only way that any Dayak tribe could achieve prosperity and fortune. Dayak warfare was brutal and bloody, to the point of ethnic cleansing. Many extinct tribes, such as the Seru and Bliun, are believed to have been assimilated or wiped out by the Ibans. Tribes like the Bukitan, who were the original inhabitants of Saribas, are believed to have been assimilated or forced northwards as far as Bintulu by the Ibans. The Ukits were also believed to have been nearly wiped out by the Ibans.

The Ibans started moving to areas in what is today's Sarawak around the 15th century. After an initial phase of colonising and settling the river valleys, displacing or absorbing the local tribes, a phase of internecine warfare began. Local leaders were forced to resist the tax collectors of the sultans ofBrunei. At the same time, Malay influence was felt, and Iban leaders began to be known by Malay titles such as Datu (Datuk), Nakhoda and Orang Kaya.

In later years, the Iban encountered the Bajau and Illanun, coming in galleys from the Philippines. These were seafaring tribes who came plundering throughout Borneo. However, the Ibans feared no tribe, and fought the Bajaus and Illanuns. One famous Iban legendary figure is known as Lebor Menoafrom Entanak, near modern-day Betong, fought and defeated the Bajaus and Illanuns. It is likely that the Ibans learned seafaring skills from the Bajau and the Illanun, using these skills to plunder other tribes living in coastal areas, such as the Melanaus and the Selakos. This is evident with the existence of the seldom-used Iban boat with sail, called the bandung.

This may also be one of the reasons James Brooke, who arrived in Sarawak around 1838, called the Ibans Sea Dayaks. For more than a century, the Ibans were known as Sea Dayaks to Westerners.