After 10 years of working for a New York City newspaper, I quit my job and bought a one-way ticket to the other side of the world. My journey is a meandering route through Southeast Asia. This piece is adapted from my blog, Packmonkey.

WE WERE CRUISING on the Kinabatangan River, deep in the jungle of Malaysian Borneo, when our guide suddenly killed the boat’s engine. Over the previous two days, Tan, from Uncle Tan Wildlife Adventures, had displayed an encyclopedic knowledge of the local flora and fauna, including Latin names and the relative obscurity of each species. He was on to something now that the rest of us had missed.

He asked for the binoculars, then focused on a spot high in the trees on the far bank. “Woo hoo!” he hollered, thrusting his arms into the air in a victory gesture. “Bornean gibbon. It’s very rare. You guys are lucky.”

Here was a wildlife guide with 11 years of experience, grinning like he’d just seen Big Foot. Tan was ecstatic but I couldn’t see more than a smudge of dark fur in the crook of a tall tree. The gibbon then swung from its perch, giving everyone a glimpse of a lanky body and long powerful limbs. It was a brief encounter, but a shiver shot up my spine. The gibbon wasn’t the first ape I’d see in Borneo, just the most elusive. The sighting sealed the deal; I am a monkey tourist.

As a North American, I don’t get the chance to see monkeys outside of zoos and circus sideshows. The closest I’ve come to “wild” over the past few years was an opening night screening of Peter Jackson’s “King Kong.” Throughout Asia, however, monkeys are part of the landscape, both physically and in the imagination.

Hanuman is one of the most important divinities in Hinduism. The monkey is one of the most auspicious signs of the Chinese zodiac. And primates appear in Asian culture high and low, from the Monkey King of the 16th century Chinese epic “Journey to the West” to Speed Racer’s sidekick, Chim-Chim the chimpanzee. Sometimes the image of a monkey seems to guarantees success. Would A Bathing Ape be such a hot clothing brand without its eye-catching simian logos?

So where was my monkey tour going to start? The most obvious choice was the orangutan, the most famous primates on Borneo. The “old man of the forest” attracts busloads of sightseers to the Sepilok Orangutan Rehabilitation Centre for twice-daily feedings. The feeding I attended delivered exactly what it promised: orangutans, up-close and personal. Half a dozen apes, as well as a few red-bottomed pig-tailed macaques, showed up to munch on bananas. The orangutans climbed pillars, they scowled, they screeched, they hooted. The crowd was pleased with these antics, but to me the apes seemed tame and aloof, like they’d long ago tired of the humans who came to gawk.

ALL PHOTOS BY MATTHEW KLEIN.

The wildest behavior I witnessed at Sepilok was a Malaysian tourist who placed his toddler son next to a grooming macaque, manipulating the boy’s hand until it stroked the creature’s fur. Despite abundant signage, the man was oblivious to the first rule of monkey tourism: Don’t Touch the Monkeys! I was hoping for blood, but the macaque just bounced away.

I wanted something closer to nature, something wild. My next stop was the Labuk Bay Proboscis Monkey Sanctuary, where the monkeys are half as lovable and twice as ugly as the meanest, homeliest orang.

There are only about 7,000 proboscis monkeys in the world, and they’re only in Borneo. Two times a day, they are lured by sugar-free pancakes to the sanctuary, which tourists can only reach via 15 kilometers of dusty back roads through a palm oil plantation.

As the name suggests, the species is distinguished by a huge schnozz. Jimmy Durante comes to mind. Actually, only the males have big noses. The females have dainty, pointy noses. The size of a dominant male’s nose plays some part in his attractiveness to females. The girls like the big beaks. Yes, bigger is better.

What’s more, the dominant male’s purpose in life is producing as many offspring as possible. To this end, he sports a constant erection, a red rocket rising permanently on the launch pad.

The proboscis monkeys in Sabah acted like all the other monkeys I’ve seen—fighting, swinging, scratching and screeching. Nevertheless, with those fantastic noses and huge hard-ons, what’s not to love?

Scheduled feedings are not exactly the stuff of a “National Geographic” special though, and it was time for me face the monkeys on their turf.

At Uncle Tan’s camp, where a collection of jungle huts an hour’s boat ride from the middle of nowhere serves as the base for nature safaris, I would find what I was looking for. I just didn’t know I was looking for it.

As we sped down the Kinabatangan toward the camp, we saw about a dozen groups of long-tailed macaques and proboscis monkeys perched in trees on the banks of the river. They barely registered our presence in their territory. These were ordinary monkeys doing nothing special, but the sight was extraordinary.

At the camp itself, a mother orangutan had built a nest for herself and her baby in a tree high above one of the huts. At the kitchen, the staff and guests had to keep an eye out for the brave macaques looking to raid the pantry. Our vigilance failed during afternoon tea when one cheeky monkey absconded with a can of powdered Milo.

On the third day at the camp, a few guests were watching the orangutans. Mama orangutan decided to move to a neighboring tree, but her baby was too small to cover the gap. It reached out in distress. Mama calmly gathered her offspring and brought it to safety. There were no theatrics, no screeching, leaping or baring of teeth. It was a moment of kinship between mother and baby, an unexpected display of great tenderness and kinship. The scene touched tourists and the Malaysian staff alike.

All along I’d been looking for something wild. In the end, however, after all the monkeys I’d seen, it was a single act of maternal instinct that proved most thrilling. •