The Proboscis Monkey of Borneo – Proof that Size Matters After All

“Take you to see proboscis monkey?” suggested the taxi drivers lined up at the entrance to the Sepilok Orangutan Rehabilitation Centre. Frankly, I had no idea what they were talking about. My visit to the Malaysian State of Sabah on the island of Borneo had two goals: see the endangered orangutans and sun bears. I’d never heard of proboscis monkeys, so later that afternoon I turned to Father Google. The moment I saw a photo of these strange primates, I knew I had to see them in the wild.

Found only on the island of Borneo, the proboscis monkey is among the largest species of primate and, like the orangutan and sun bear, it’s an endangered species. Males measure up to 30 inches in height and weigh up to 66 pounds, while females are slightly smaller. Their most startling features, however, are their huge noses and pot bellies. Females have perky, upturned noses, but the males have giant bulbous noses that measure up to four inches long. Intrigued, I signed up for a day trip to the Kinabatangan River and crossed my fingers for a successful sighting.

The following day I was picked up at my resort at noon for the two-hour drive to the river landing. Our group of eight donned life jackets and climbed into fiberglass boats with powerful motors, necessary for swerving around logs and piles of detritus floating down the swiftly flowing river. Our guide briefed us before jetting away from the pier. “I can’t guarantee we will see proboscis monkeys, because this is the jungle. They go where they go. But we’ll do our best to find them, and we’re usually successful.”

He need not have provided the disclaimer. Within 15 minutes the captain idled the engine and angled toward the shore. Our guide pointed to a cluster of tall trees. “Look for the bright orange color,” he shouted. Rustling leaves. A flash of orange. Suddenly, I saw one. Then two, then an entire family skittering around the branches. As the captain maneuvered closer, I was startled to see one huge male looking down on us with seeming disdain. Tucked into a crook of the tree, he reclined regally with one foot up on a branch. His big belly reminded me of my late Uncle Bee, who would inevitably fall asleep in a chair after Thanksgiving dinner, feet splayed, gut spilling over his belt, with a precariously tilted unfinished can of beer in one hand.

But it was the monkey’s enormous schnoz that most captivated me. Bulbous and red like an overindulgent alcoholic, it hung well below his mouth. How can they even eat, I wondered. I turned to the guide. “There must be some advantage to the big nose or they wouldn’t have evolved this way,” I said. The guide had no answers.

I later learned that scientists suspect the large nose allows the males to vocalize louder. Indeed, studies of the proboscis monkey in the wild have confirmed that the males with the largest nose always have the biggest harems. We saw many proboscis monkeys during that two-hour boat trip, but none more spectacular than the one I dubbed Uncle Bee.

That evening, I sent a photo of him to my sister, Linda, who is crazy about monkeys. I explained the theory about the big nose allowing the males to attract more females. She replied, “So, size does matter after all – LOL.” It would seem so!