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  • Writer's pictureDr. April Reside

The Return of the Lobos de rio (Giant River Otters)

Updated: Nov 5, 2019

Wandering back to camp one afternoon, Beloved muses “Wanna go for a paddle on the cocha [oxbow lake]?” Damn fine idea, I thought. We climbed into the little dugout and pushed out into the lake with the heavy carved wooden paddles. Directly across from the station was four least grebes, and a group of Muscovy ducks (strange critters!). We paddled on into the setting sun. It was so calm, and so peaceful. Except for the midges. And me cursing the midges, incessantly scratching their bites, and halting paddling to scratch and curses. We found a group of hoatzin, who startled as we got close, flying off in their not-exactly-graceful style. Green ibis and limpkin were skulking in the reeds. Further on, another group of Hoatzin, and a hoatzin on a stick nest, in a pile of dry sticks over the water. Large overhanging logs had Rhynconycteris naso, an adorably scruffy little bat, lined up underneath them, just as I’d seen in Yasuni. It was starting to get dark so we turned around headed back to the little jetty. Several groups of monkeys were settling in for the night in the large trees on the river bank. The midges were replaced by mosquitoes, excellent at biting through clothes, and it was getting properly dark, so we headed straight back to shore.

Two days later, we wandered out the 7-odd km to Playa Bonita again to check the trail cameras we’d set up three days earlier. The heat and humidity ramped up a notch so we were sweat machines before we even thought about walking. The first trail camera had little but falling leaves. The second trail camera had the sun bitterns strutting back and forth like little show ponies. We waded across the creek to the opposite playa and the third camera … was full of images and videos of giant river otters (Pteronura brasiliensis)! Otters wandering over the sand, otters chattering to each other, otters trying to keep up with other otters; a minimum of five, but possibly six. Wow!

Giant river otters
Giant river otters, on the trail camera at Playa Bonita

We wandered back in the dark, slowly, spotting frogs. The little froggy hollow that was full of Allobates femoralis and other tiny frogs during the day had a small Caiman in it – its eye shine so bright it wasn’t to be missed. Further on I saw a giant, bright yellow frog with a red pattern down its back, almost a lichen-like pattern. It did a characteristic dive-down-a-bolt-hole when we approached, so was quite obviously a large Leptodactylus species, probably Leptodactylus knudseni. Further on, we found my favourite frog – the adorable Ceratophrys cornuta – in the middle of the trail, in exactly the same spot we’d seen it three nights earlier. We could identify the curve of the tree root behind it from the photos we’d taken last time. If it lives there on the trail, I’m so relieved we didn’t stand on it!

Inverse Frogs
Inverse frogs: elachistocleis bicolor (left) with almost no mouth; and ceratophyrs cornuta (right), which is predominantly mouth

Beloved wandered ahead to a low-lying open area and then waved me on urgently. I quietly rushed up to find a Brazilian tapir! Incredible! It wasn’t so excited to see us and charged away through the forest with a crash. How nuts to have seen two tapirs this trip. Once we’d recovered from this excitement we stopped to photograph more frogs, so I left the professional to the job and wandered ahead. I found a small birds nest covered in lichen so thought I’d wait patiently for beloved to catch up so I could show him. Waiting quietly in the dark I could hear a little bit of movement in the forest. The forest is so loud at night: cicadas are bleating, all number of insects are screeching, night birds are calling and numerous noises we can’t identify. So I often can’t hear every animal moving slowly through the vegetation. Standing quietly, however, I could hear something. Lo and behold – ANOTHER TAPIR! WTF? Two tapirs in one night!? This time it was me who was urgently waving beloved up, and he rushed up to see it briefly before it too crashed off into the forest. As it crashed away from us, I could see what looked like an udder under its belly – so presumably it was a female had young at some point.

Snake - Corallus hortulanus
Corallus hortulanus

Not much could top two tapirs in one night, but wandering on further I saw a boa slithering along the side of the track. I indicated that beloved should check it out by crying “SNAKE!”. It had a shiny rainbow sheen to its brown-and-black patterned body, giving it away as a rainbow boa (Epicrates cenchria). Two boas in two nights! Corallus hortulanus and Epicrates cenchria.

Rainbow boa
Rainbow boa, Epicrates cenchria

It was getting past my bedtime when I heard some leaves falling from above I looked up and saw bright eyes staring down at me. The round face and constant movement gave it away as a kinkajou, a cool critter. But very high up, directly above us, which made looking at it difficult and was hard on the neck. I dropped my gaze to rest my neck – and found myself staring directly at an opossum! It was a total scruff-nut, not ‘clean’ like our Aussie possums, the more scraggly Didelphus marsupialis. A cool critter nonetheless. We were almost at camp when we found a pacarana not far from our tents. It was midnight so I struggled to raise interest as I stumbled off to have a cold shower and crash into bed. What an amazing place.

Didelphus marsupialis
Didelphus marsupialis

There are so many crazy noises in the soundscape, particularly in the dawn chorus, that we can’t tell what must be making most of them. We are spending long nights finding critters so often trying to make up a bit of sleep in the morning. But it is difficult to sleep through the dawn chorus ruckus. One particularly distinctive, loud noise woke us up one morning, with lots of different components to the loud nasally calls and shrieks. Some sounded like cute sneezing noises, others funny wails. In the half-asleep haze of the dawn a sudden realisation hit. “Giant river otters!!” I called, waking beloved up. They have returned to the station! Rubbing our eyes we stumbled out of the tent and into the nearest clothes and tried to find a spot we could see the river. All of the tent platforms are along the Cocha (oxbow lake), so we were only 30 metres from the water, but the forest is so thick that we can’t actually see the water. But the calls were so loud. Wandering along the track we found tiny gaps through the trees. “I saw an otter!” beloved cried. We found a fallen tree poking out into the river so climbed through the tangled vines and trees and out onto the log. We found the group of six, hunting efficiently, performing coordinated dives and surfacing each with a fish. They held the fish between their two paws, while munching them down. They swam over to our log, baring their impressive canines. I was out in front, and called “Should I be worried?” as they approached. After a bit of investigation they vanished underwater and surfaced further out. We saw an osprey swooping above them, catching fish on the periphery on the circle of otters. It was the first time we’ve seen an osprey on the cocha – was it following the otters? Presumably these otters are the same ones we got footage of at Playa Bonita. We wondered how they got to the Cocha. There are lots of creeks, but how far did they travel across land? We watched them cavorting, fishing, and calling to each other. We sat back on our log, watching the otters retreat towards their den; and saw the jacanas, green ibis, anhingas and limpkins starting their day. What a morning! Time for breakfast.

Giant River Otters
Giant river otters (from the camera trap at Playa Bonita)



The blog post above has been kindly provided with permission by Dr. April Reside, Postdoctoral Research Fellow at the Centre for Biodiversity and Conservation Science at the University of Queensland. Please check out her blog Conservation on the Fly for more fascinating entries:

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