Monkeys, Agoutis and Sloths, oh my

view from the dining hall

view from the dining hall

Today we toured a portion Barro Colorado Island, a global icon for biodiversity and rainforest ecosystem research. The island and surrounding lands are owned by the Smithsonian Tropical Research Institute, and we intermittently passed historical study sites along with researchers and their ongoing projects (like lianas’ function as lightning rods). Early on the path parallelled a huge colony of leaf-cutter ants, which initially wasn’t very engaging as we’d seen them almost everywhere. However, a few of the workers were observed carrying from the mound a dead or dying virgin queen. Without going into detail on their eusocial dynamic, this doesn’t seem like a common phenomenon at all, and I wasted a lot of brainpower puzzling over what factors could have led to her dying in the pampered confines of the nest.

general worker activity, sans princess

My favorite moment was when the group stopped to rest and we were passed overhead by a troop of howler monkeys; hearing the howls every day prior built up a lot of anticipation. The troop consisted of 4-5 adults– it’s hard to tell when they’re not all in view simultaneously– and one baby a fraction of the others’ size swinging in their wake. At least one of the adults were male, and the baby was estimated at 9-12 months old by Alex, citing maturation into black fur and behavioral cues (hovering near the mother but swinging independently). All of them were foraging and lazily popping leaves into their mouths, but two of the larger adults descended a few feet further to the ground, lay stomach-down on thick branches, and stared intensely back at us. Given that we weren’t howled at and they took their sweet time leaving, we were seen as more of a curiosity than a threat, but years of researcher activity have definitely familiarized them to the conspicuously colored ground apes. It was also shared among the group that the howler monkeys were of the Golden Mantled variety, and they have prehensile tails exclusive to New World monkeys AND unique prints on those tails and their fingers.


I regret not being able to get pictures [but Logan and Catherine did, badger them!], so here’s a shutterstock image representing the general view we had.

Since there are only so many hours in the day, we’ll wrap up with some miscellaneous fun facts, the first two relayed by our guide Iann:

Fractured habitats not only affect migration, but create opportunities for increased variety and effectiveness of pathogens.

Bufotoxins (from native toads) can act as powerful muscle relaxers, and selective injections have shown temporary effectiveness in treating arrhythmia, stuttering, and strabismus.

According to WebMD, with the amount of while DEET we’ve ingested, we thankfully shouldn’t discover organ damage until after getting home 🙂

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