A Big Fish Expeditions Trip Report
By BFE Trip Leader Andy Murch
Amazing Encounters with enormous Anacondas!
Giant anacondas everyday. Over the course of the week we saw some huge females with bodies thicker than my thigh, and lots of smaller males, but among green anacondas, small is a relative concept because most of the males were 3-4m long!
The hunt for Anacondas
Anaconda diving is a simple process. Each morning, our expert guide chose a different section of the Rio Formosa known to have resident giant anacondas. The river itself is open to the public but accessing the river is a different story, involving special agreements with farmers that own the forested land around Bonito.
We used two small aluminum boats which we manhandled down the bank and then motored upriver where the hunt for anacondas began!
Rain in the River
Although the weather was excellent while we were there, just prior to our trip it had rained in Mato Grosso, so in some areas the water was was quite cloudy. On the morning of our first day, we dove a section of the Rio Formosa that passes through farmland which is particularly prone to run-off. We did not see any anacondas that morning but we did find a Jacare Caiman resting under the water. We slipped in and tried to approach it but the viz looked even worse when we actually started snorkeling.
Diving in a tropical forest
In the afternoon we relocated to a stretch of river that passes through a protected area in the middle of the jungle. There the viz was better, and we found our first female green anaconda basking on the bank. She was an impressive 5-6m specimen. As we drifted downstream, we came across a series of small waterfalls and rapids that we had to manhandle the boat over. Between guests and crew we were soon downstream of the falls and back on our way.
Males on the bank
Later we came across two males curled up in the undergrowth where a large female is often seen. Anacondas are usually solitary animals but September is their mating season.
Better viz and multiple anacondas
The next day we returned to our original spot. The viz had started to clear and we found a large female resting in the shallows. This spot was too shallow for scuba so we slipped in on snorkel and approached the enormous reptile slowly so that we could enjoy her markings and immense girth before she swam away.
We found multiple males along the banks, all seeking the attention of the resident females. We did not see them actually mating but the number of males in close proximity to each other, implied that they had either just finished mating or were preparing to do so.
Underwater, the relatively small (but still enormous) males looked very graceful, snaking along next to the muddy river bank.
Diving in a pristine river setting
The next morning we went to gorgeous spot deep in the forest. The water was crystal clear and the snake action was excellent. The largest female we saw there was around 5m long, but there were also numerous males to photograph too.
Bird Life in the forest
Kingfishers, hummingbirds, hawks, parrots, and toucans were everywhere! While we traveled downstream scanning for anacondas, we snapped away at the colorful avian life at every turn.
We also saw quite a few monkeys in the trees that overhung the river banks. The most common (and easiest to photograph) were the Tufted Capuchins that looked as though they had just come from the hair salon.
Photogenic males and monster females
Although the prize was always getting time underwater with big females, the males were often easier to follow and easier to compose shots of because the females were so big, it was almost impossible to get their entire bodies in the frame.
Epic encounters during a cold snap
On our last day a cold wind blew in and our guides became despondent, warning us that the snakes often stayed underground during a cold snap. Fortunately, they were wrong and we had some of our most memorable encounters. Almost immediately, we found what we think was a smallish female sunning herself on a log.
The perfect anaconda
Eventually, she slipped into the water but remained under a thick branch where we could photograph her to our hearts content.
Males down river
When the female finally swam off, we returned to the boat and continued downstream where we came across numerous males sunning along the banks. Each one slipped in during our approach, so we followed them underwater as best we could, until one by one they disappeared into the undergrowth.
A resounding success
It was a great trip. Over the course of the week, we all captured great shots of numerous giant anacondas in a variety of settings, so we are looking forward to repeating the experience next year. In 2023, we are running three back to back trips. Two are already full but our August 22-28 trip has one spot open, so if you would like to join us, please let me know as soon as possible! Anaconda Diving Expedition 2023