Stories
We found (and yelled at) a crazy tentacled caterpillar
On my recent travels through the Peruvian Amazon, I came upon the craziest caterpillar that I have ever seen and subsequently yelled at it for hours. Why did I yell at it? Well, its strange behavior towards sound was why I noticed it in the first place. I had just climbed to the top of a canopy tower overlooking the rainforest when I called to my group below me – suddenly a flash of movement at eye-level caught my attention.
Hear about my caterpillar adventures below. And to check out more otherworldly jungle creatures — and even help with scientific discovery — join in our Wired Amazon project!
On a nearby tree branch hung a caterpillar with four strange tentacle-like appendages protruding from its abdomen. I might never have noticed this small brown insect had it not been for its unusual movement: noises would cause it to fire its tentacles in randomized directions, then slowly twirl back into a spring-like “ready” position to await its next alarm. This reaction to noise was so peculiar that once my group joined me around the creature, we proceeded to take turns yelling at it and filming its contorting reactions for over an hour.
After a little research, I found that this caterpillar is in the moth family Geometridae and is in the genus Nematocampa. Also referred to as ‘horned-spanworms’ or ‘filament bearers’, these peculiar caterpillars can be found in North America and the Neotropics.

David Wagner, in his field guide ‘Caterpillars of Eastern North America,’ notes:
“It is difficult to imagine what the [Nematocampa] larva is mimicking, but the overall effect is not unlike a fallen brown flower with exerted stamens. Alarmed caterpillars shunt hemolymph into filaments, enlarging them by as much as twice their resting length.” [1]
What Wagner seems to be proposing is that the larva movement is similar to the way flowers or other plant matter move in the wind: the behavior more effectively blends the caterpillar into its surroundings.
Other potential purposes this behavior may serve to include:
- The tentacles extend when the caterpillar is alarmed so that an attacking predator (such as a bird) has a higher probability of snagging a tentacle, as opposed to the main body, so that the caterpillar may drop away and escape with its life (similar to how some lizards are able to lose their tails).
- The setae, or “hairs,” located at the tip of a long tentacle could be highly sensitive vibration detectors that are able to sense predacious birds or insects that make nearby sounds [2].

What do you think? Screaming at caterpillars doesn’t fall into most people’s job descriptions. But that’s exactly what I found myself doing a couple of weeks ago in the Peruvian Amazon, all to bring the story of this bizarre organism to you! Leave a comment below and let us know how you feel about this peculiar caterpillar found in Tambopata, Peru.
To discover these fascinating caterpillars, along with dozens of other incredible species, book your dream trip to the Amazon today!
By Aaron Pomerantz, Entomologist
You can follow me on Twitter @AaronPomerantz
-
What our guest say
-
- Valuation Excellent
- 5/5
Maria Carrero June 2026
Lauren Kuenstner June 2026
Adam C June 2026
Perry Killam June 2026
Brad Taylor-White June 2026
Sue_szb April 2026
Beam May 2026
David Staro May 2026
Serg Averkin April 2026
Carlotta May 2026
Asha S May 2026
Laurence W April 2026
We stayed last february for 4 nights in the TRC lodge. I never could have imagined that I would explore the amazon in such confortable and immersive way. The lodge itself is such a luxurious place, in the middle of nowhere! The food was nicely curated everyday to offer new bits and pieces of the Peruvian cuisine. The absolute highlight of our stay here was for sure the activities and our guide Carmen, who accompanied us everyday! We were able to choose our everydays activities with our very reduced group and our guide. Carmen guided us on very activity, spotting and explaining what animals we saw and interesting facts about our surroundings. Her knowledge and excitement were so infectious that it would even make the sightings even more special! Read all
One of the most unique experiences we’ve had! You are deep in the heart of the Amazon and truly feel immersed in nature. Our guide Dino was awesome and taught us so much about the rainforest-he is like a walking encyclopedia, and his love for the forest really shows. Also very unique to listen to nightly talks from the research team-it really adds to the experience. Food was great and staff very friendly. Bring lots of bug spray and an adventurous spirit! Read all
The lodge was fantastic; they were very attentive to our needs. The dining staff brought special bread for my wife because of her celiac disease and offered to prepare dishes specifically for her to meet her dietary needs. The lodge guides were truly knowledgeable and went out of their way to help us see all the local wildlife. I especially loved the mosquito net service they provided. I was worried we’d be eaten alive, but their setup is fabulous; I had no concerns once I saw how they installed the impenetrable nets and curtains. The meals were as good as—or better than—anywhere else we ate in Peru. We saw the following animals: macaws, parrots, parakeets, pale-winged trumpeters, tamarins, caimans, capybaras, and a ton of insects on our night hike. Read all
We had an excellent guide who was very knowledgeable about the local animals, birds, and plants. I learned a lot. We also participated in the Wired Amazon experience and just received the video clips of the animals that walked by - ocelots, agoutis, ... some amazing animals. It was fun to set up the camera traps, and now I'm inspired to get one for our backyard. Read all
Refugio Amazonas was one of the most memorable and immersive experiences of our entire trip to Peru. From the moment we arrived, it felt like we had entered a completely different world. Waking up to the sounds of the rainforest, exploring the Amazon with knowledgeable guides, spotting wildlife, and disconnecting from everyday life created an experience we will never forget. The guides and staff were exceptional throughout our stay. Everyone was warm, welcoming, knowledgeable, and clearly passionate about the rainforest and the guest experience. Their enthusiasm and expertise added so much to every excursion and activity. For this type of Amazon adventure, Refugio Amazonas felt top-tier. The wildlife experiences were remarkable, the setting was beautiful, and the overall level of immersion was exactly what we were hoping for when we added the Amazon to our Peru itinerary. Read all
Wow what an experience! If you want to be fully immersed in Amazon life in a wonderful , comfortable eco lodge, and not have expectations of a 5 star city hotel (I'm not sure why you would, but some reviewers seemed disappointed it wasn't!) you will love this. You will be in a group, 6 in ours, but you don't all have to do the same activities, you just join another group. Plenty of spaces to chill and downtime if you need it...its hot and humid! There's a fan in the room and I heard the superior rooms have a fan under the mozzie net. Take a torch! We were never bitten, used deet repellent only. They provide rubber boots if you want them, some of the trails were very muddy, but we managed in our walking boots. We loved the open wall to the jungle, despite some bugs, but not too many surprisingly. Sooooo much wildlife, all sorts of monkeys, otters, turtles, caiman, different birds, capybara etc. Luis M was our guide, a local, and he could spot a spider from 5 metres I'm sure... great sense of humour and a wealth of knowledge, loved him. We spent 3 nights 20th-24th April, it rained on a couple of occasions but not much. Perfect holiday for an immersive wildlife experience! Read all
Beautiful lodge in the rainforest, very well maintained and clean. We had a lot of fun and excellent guides. The rooms and facilities were top-notch! Read all
We stayed at Posada Amazonas Lodge in May 2026, and it was a truly unique experience. It’s important to note that the concept is unlike a traditional hotel: the rooms (the lodge has around 30 in total) are built entirely of wood and open completely to the rainforest, with no windows. The walls are about two meters high, and everything is open-air, meaning you can hear your neighbors as well as the sounds of the forest throughout the night. There is a hot-water shower with drainage flowing through wooden beams beneath the floor, and the beds are protected with mosquito nets. The food is delicious and nutritious, and one pleasant surprise was the excellent Wi-Fi connection (Starlink) available both at the lodge and on the boats. The logistics are flawless from the moment you land in Puerto Maldonado, including a short car ride (accompanied by a security company) followed by a forty-minute cruise along the Tambopata River. The staff is incredibly friendly. Our guide, Luis M. (a member of the local community that manages the lodge), was simply outstanding, with eagle-eyed vision for spotting wildlife and always wearing a smile. Tour highlights: Canopy Tower: a 42-meter tower rising above the treetops with panoramic views. We loved seeing the river, the rainforest, and even the distant Andes Mountains on the horizon. We returned at night during a nocturnal wildlife tour, where we spotted tarantulas, white sloths, and tree frogs. Lake Tres Chimbadas: a peaceful catamaran ride (without a motor) where Luis showed us a group of red-bellied monkeys, giant otters, and caimans. The scenery and tranquility are incredible. Trek to the “Great Tree”: a forest hike where we saw deer, jaguar tracks, a three-toed sloth, and more wildlife. At the end of the trail, we reached the gigantic ceiba tree: around 500 years old, approximately 60 meters tall, and with an impressive 11-meter base diameter. Highly recommended for anyone wanting to experience the true Amazon! Read all
An exceptional experience that truly exceeded all expectations. What impressed me the most is that here they genuinely want to make your stay as comfortable as possible — and that, to me, is what real high-level service is all about. The guide really tries to fill every excursion with emotions and memorable moments, turning simple activities into meaningful experiences. The kitchen team puts great effort into variety and introduces you to Peruvian cuisine — it feels like a small гастрономic journey. Housekeeping works like invisible bees — you don’t notice them, but everything is always perfectly taken care of. Another big highlight is the comfort level: stable electricity and surprisingly good internet both on the way and at the lodge, powered by Starlink. Having this level of connectivity in the middle of the jungle is something truly special. From reception and the bar to the boat driver — everyone is genuinely warm and happy to have you. You can really feel that each person is a small but important part of one big system delivering outstanding eco-tourism service. Bravo — achieving this level of service in the wild is not easy, and it shows. This experience was very valuable for me and my family. I won’t get tired of thanking you for the emotions you gave us. Highly recommended. Dear travelers — don’t hesitate. Go, enjoy the incredible nature and the level of service. This is something you will remember for a lifetime. Read all
We had the most amazing time at Refugio Amazonas for 3 nights, with a huge thanks to our guide Juan Carlos! On the first afternoon we sat down and planned our activities, which we loved! We came face to face with hundreds of birds, tarantulas, leaf carrying ants spanning 10 meter motorways to work and deliver the leaves to the ant house for food, parasites, and even leaves that cause natural dyes on oxidation - we learned so much. Carlos was genuinly interested in showing us everything the jungle had to offer, humorous and caring too. Carlos knew anything and everything about what was around us, pointing out things and creatures that the untrained eye would miss, carrying a telescope at all times for us to see the birds, ensuring we got magical videos on our phones using the telescope! Read all
Many thanks to Refugio Amazonas for an unforgettable experience! Brenda and team were so wonderful and accommodating, and Alan was a great guide. Thank you for a memorable experience! :) Read all
We had an excellent time at Tambopata research center. We are tourists like most who now visit the center, but it’s great to know that you can support research and the local community by visiting a place like this. Our guide for our trip, Esau, was extremely knowledgeable and showed great passion for his job. He described it as a hobby and he would get very excited if you spotted a specific bird or a tree. His specific knowledge about each and every creature in the forest was very impressive and I would recommend asking for Esau to be your guide in the future if you plan to visit. The hotel itself is unique. You are in the middle of the Amazon rainforest - the accessibility to nature is second to none. There are no windows in the hotel rooms. We had bugs in our room, of course, but the mosquito nets keep everything out and, actually, we both slept very well. The bar staff, Harrison, is very knowledgeable with drinks and works very hard. The food isn’t the best you’re ever going to have, but you have to remind yourself you are in the middle of the rainforest and that it takes a 6 hour round trip to get to the nearest town, and so the job that the hotel does in respect of the food is actually intuitive and very good. I would recommend this hotel to my peers and I would love to visit again in a few years time. Read all
-
March 16, 2024 The Fascinating Jaguar Mating Behavior: Insights ...
Thanks to the AmazonCam Tambopata, our project that studies the jaguar population through camera traps Tambopata in Madre de Dios - Peru, we can learn more about this fascinating a...
Read more -
October 30, 2017 Crimson Forest: A Vampire Tale...
I hadn’t originally intended to cover vampire bat facts in one of these blog installments; however, when I saw the fascinating and unique footage (perhaps representing the only f...
Read more -
September 03, 2022 The Best Green Hotel in South America...
Considered the Oscars of tourism, the World Travel Awards recognized Tambopata Research Center as the best Green Hotel in South America. During the last 3 years, despite the pande...
Read more