About 100 yards from the headquarters of Gunung Mulu National Park - a rain forest preserve famous for huge caves, massive bat colonies, and jungle trekking - the park receptionist spots me walking toward the building.
She takes one look at the black pig grease on my face - smeared over my eyes, across my cheeks, all over the forehead, on my nose, and even the ears - and then doubles over with laughter.
She doesn't have to ask. It's obvious: I have been to a village wedding, the marriage between Freda Ugum, a woman of the Melanau ethnic group who is in her mid-20s, and Kuah Hock Jun, a 30-something Chinese groom.
Intermarriage between Sarawak's 25 ethnic groups has been common for generations. But until recently most of the mixed marriages have been between indigenous groups with similar backgrounds. Now, though, mixed marriages have expanded to encompass unions with Chinese, Malays, and even Europeans and Americans.
This is Mr. Kuah and Ms. Ugum's second wedding ceremony. The first - attended largely by his friends and family two weeks earlier in the oil-drilling town of Miri - was a traditional Chinese affair in which Ugum wore a Chinese bridal dress.
Now, it's Kuah's turn to wed in the tradition of his bride's family.
A young man stands by the bank of the river, welcoming guests as they arrive in canoes at the home of the bride's father. The sound of a gong reverberates through the air, reminding neighbors that the wedding is today. A large suckling pig is being roasted over an open fire.
Kuah arrives near the front of a procession, bringing gifts for the bride's family. He wears a white singlet, black biking shorts covered by an embroidered cloth, a knife, and a heavy feathered and beaded hat, which looks like something an American Indian might wear in a John Wayne movie.
During the ceremony, Ugum's father and uncles lecture Kuah about the need to respect Melanau customs and tradition, particularly once he has children.
"Don't forget to say hello to your relatives, to all the members of your extended family," Joseph Ugum, the bride's father, tells the groom, "even if you meet them on the street in the city."
Kuah wrings his hands and takes a deep breath. He's obviously nervous. He tells me later he doesn't speak Melanau, so he can't understand the speeches. He also confides that the feathered headdress is really heavy.
There are no roads leading to Mulu, the riverside village where Kuah and Ugum are married. But it may as well be on an Interstate highway compared to Bario and the Kelabit Highlands, located upcountry 50 miles away.
The only way into Bario - other than hiking for nearly two weeks through jungle and across steep mountains - is by a Twin Otter 20-seat propeller airplane. Less than 70 years ago, people here had never met a white man.
But intermarriage in the highlands is even more common than in Mulu, and the spouses often hail from much farther away.
The region's renowned headhunters met their first Westerners - Australian missionaries - in the late 1930s, and then European paratroopers fighting the Japanese in World War II.
When British airman Tom Harrison parachuted onto the lush highland plateau in 1945 to set up a base of operations behind Japanese lines, the Kelabit chiefs who greeted him had a decision to make: cooperate, stay out of the conflict, or cut off Mr. Harrison's head. They decided to cooperate.
Today, the children and grandchildren of the chiefs who welcomed Harrison into their community have gone a step further. They're marrying Westerners in droves. And Harrison, who stayed after the war, was one of the first foreign grooms.
"In those days, we didn't want to marry other races," says Tamah Saging, a retired chief who estimates he's about 90 years old. "It must be between Kelabits and Kelabits."
But when Mr. Saging's only son - who until recently was director of immigration in the Sarawak state government - decided to marry an Englishwoman, Saging simply shrugged his shoulders. "What to do?" he says. "I can't say anything."
In some cases, almost all of a family's members have chosen spouses from overseas.
Lilla Raja has been married to Tony Hodder for 12 years. Mr. Hodder, who works in the oil industry in Miri, is originally from Devon, England. Ms. Raja's four sisters have also married Europeans - two Englishmen, a Scot, and a Dutchman. Her eldest brother married a Canadian and moved back home with her. Only her younger brother, Romeo Peta, chose a spouse from closer to home. His bride, Priscilla, is Malay. (Malays, the largest ethnic group in Malaysia, are Muslim. Kelabits, one of the smallest groups, numbering about 5,000, were animist until after World War II; now they're Christian.)
"The Kelabit community is very small," says Raja, "and we're closely related. So you don't really think about getting married to them."
Many meet someone from another nationality when they leave their villages to attend boarding school in Marudi and often remain there afterward. "Nowadays, people with good education, they're bound to meet another person ... from somewhere," says Jaman Riboh, the owner of a local guest lodge.
David Bennett, an Australian pilot who met his Kelabit wife in Bario, believes history also plays a role in the East-West marriages. Western paratroopers and missionaries did more than liberate the province, he says. They set up Bario's first schools, introduced cloth and modern medicine, and supported Sarawak during a war with Indonesia in the 1960s.
"Everything they've seen Europeans do there is for the good of them," says Mr. Bennett.
So why are Western men interested in Kelabit women?
The stereotype is that older white men are attracted to beautiful young Asian women, who are looking for a rich husband or boyfriend. But that's not the case with the Kelabit, says Hodder.
The Kelabit people are outgoing, have good principles, and are progressive in their thinking, he says. "I had absolutely nothing when I met my wife, and that didn't matter."
"Kelabit people just give, give, give," adds Bennett. "That's the sort of people they are. You give them something, they give three back."
Back by the river, as I say my goodbyes at the wedding, one of the village elders, who is also the bride's uncle, approaches me. "Do you remember my name?" he asks.
I have forgotten. "Maybe you can help me out," I say.
"No problem," he replies, taking his hands from behind his back. But instead of telling me his name, he rubs grease taken from the black pots used to prepare the wedding feast across my face. Up until then, I hadn't realized that other guests had also been victims of a traditional prank, though it seems no one had as much grease on their face as I did.
The bride and groom, meanwhile, were waiting playfully behind their uncle, with a bottle of rice wine in hand to toast my predicament.