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Chasing Orangutans Into an Unknown Frontier

After a year of planning, fundraising, and mental preparation, I have finally arrived in West Kalimantan, Indonesia on the island of Borneo to begin my National Geographic Young Explorer’s Grant project. I’ll be venturing deep into the rainforest of Gunung Palung National Park, where I’ll be following male orangutans (Pongo pygmaeus wurmbii) outside the borders of established research areas. I’ll be entering into mysterious areas under the shadow of Mt. Gunung Palung, places where few have ventured into and where none have followed orangutans. I’ll be exploring the unknown.

© Robert Rodriguez Suro
From above the canopy, the rain forest looks like a mysterious array of “broccoli, broccoli, broccoli”, and it is difficult to appreciate the wide diversity of terrain and biology that lies beneath. I don’t know how far in the orangutans will take me, but I will have to navigate my way under the shadow of the canopy, keep up with these males, and eventually make my way back home. (Photo by Robert Rodriguez Suro)
© Robert Rodriguez Suro
Orangutans are the most arboreal of the great apes, but will occasionally come to the ground. This flanged male, Codet, seems to come to the ground more often than other males I’ve encountered. I hope to document interesting idiosyncratic behavior such as this throughout the year. (Photo by Robert Rodriguez Suro)

I’ll be tracking these male orangutans with GPS, in order to learn more about their territory size and ranging patterns. It’s logistically very difficult to follow orangutans in such remote areas away from an established research camp. Because their home ranges are so large that they extend beyond research areas, no one has managed to map out the full range of an individual male from this population. I’ll be the first one to try it. I have no idea what to expect, other than the fact that it will be incredibly tough. These males will be taking me up and down mountains and valleys, across treacherous rivers, and deep into swamps. Somehow I’ll have to deal with these challenges.

© Robert Rodriguez Suro
Some males take longer to develop the cheek flanges, and some adults never develop them at all. These alternate flanged/unflanged morphs may be different reproductory strategies. Unflanged males, such as Jumanji here, tend to be more transient and will not settle in one place for long. This makes it difficult to follow them, and so it is one of my goals to really improve the data on unflanged male ranging. (Photo by Robert Rodriguez Suro)

By following these males wherever they go, and building an accurate model of orangutan ranging, I may uncover what drives these males to venture so far out from their core area. Perhaps the food availability is not equally distributed across their habitat, and far away areas can provide sustenance when nothing is fruiting in their core range. But I can only speculate at this point. If the data from this project supports a hypothesis like this however, it will be incredibly valuable data for conservation planning and land management, as it will help show how much habitat and feeding tree diversity an orangutan needs to be healthy.

© Robert Rodriguez Suro
When the terrain does not work well for tree swinging, orangutans will find alternate ways to move from point A to point B. Here, Codet crosses a large gap by walking on a fallen log. I can only imagine what sort of terrain these males will take me to this year. (Photo by Robert Rodriguez Suro)

Funded by the National Geographic Society

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