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
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Such a wonderful experience deep in a part of the Amazon, Tambopata NP. They really involve you with what is happening at the research centre with evening lectures. The meals are outstanding and the rooms are comfortable and I had the best sleep. Dino our guide was outstanding. The river trip to see the Macaw claylicks was a beautiful outing. We saw Capybaras along the river and it was very scenic. The staff are friendly and very engaging. As a tour operator who sends clients to AFRICA for safari, I was hugely satisfied. Thank you, gracious. Food & drinks: Good was simply delicious Read all


An amazing experience in the Peruvian jungle. the information about the centre was very accurate so I knew what to expect but was blown away by the experience and competence of my guide for the four nights, Juan Carlos Yatto. JC was looking for birds for me from the moment he collected me at the airport, so we saw birds on the drive and on the boat ride as well as on the excursions themselves. I was in Peru three weeks and JC was my best guide by far. Don't miss the clay licks for sure, and the tower is also well worth the climb. Food and people are wonderful and the research very interesting. Read all


Das Tambopata Research Center ist eine wunderbare Lodge im Nationalpark Tambopata. Die charmanten, miteinander verbundenen Aufenthaltsräume und Zimmer befinden sich auf hölzernen Stelzen. Bei den offenen Gemeinschaftsräumen gibt es gemütliche Sitzecken, eine wunderbare Hängemattenrelaxzone und einen herrlichen Restaurantbereich, wo zu jeder Zeit Tee, Kaffee und Wasser zur Verfügung stehen. Die stilvollen Zimmer verfügen über bequeme Betten mit Moskitonetz und moderne, saubere Duschbereiche. Die Research Center Lodge mit den Forschungseinrichtungen liegt inmitten des Regenwaldes umgeben von der reinen Natur mit der fantastischen Flora und Fauna, welche dort auch weiterhin erforscht und geschützt wird. Jeden Abend gibt es dazu sehr interessante Vorträge. Die Mitarbeiter sind sehr freundlich, offen und zuvorkommend. Die Buffets waren sehr köstlich und reichhaltig mit Gerichten aus der Region. Es wird großer Wert auf ökologische und nachhaltig umweltschonende Bewirtschaftung gelegt. Von der Lodge aus ist es möglich, mit ausgebildeten Guides in Gruppen von maximal 6 Personen verschiedene Exkursionen zu machen. Speziell Timo war ausgesprochen freundlich, auf unsere Sicherheit bedacht, ging auf die individuellen Interessen der einzelnen Personen ein und vermittelte uns in seiner kompetenten Art umfangreiches Wissen über die Pflanzen- und Tierwelt. Er hatte dabei die wunderbare Fähigkeit, versteckte Wildtiere zu entdecken, und verschaffte uns wunderschöne Momente, auch durch das mitgetragene Teleskop, wodurch wir der Tierwelt näher sein konnten. So sahen wir u.a. Brüllaffen, Kapuzineraffen und Spideraffen mit ihren Kindern, viele Vögel insbesondere Papageien wie z.B. Scharlach- und Gelbbauch-Aras sowie Wasserschweine und verschiedene Insekten. Wir können diese wunderbare Lodge absolut weiterempfehlen. Die herrliche Tier- und Pflanzenwelt in dem wunderbar erhaltenen und geschützten Regenwald des Amazonas war auf unserer Peru-Reise ein wirklich fantastisches Erlebnis! Read all


Rainforest Expeditions is a wonderful company and the Posadas Amazonas lodge is a beautiful location to spend your time in the Amazon. The staff are all incredibly kind, helpful, and knowledgeable. The tours were very fun and we saw lots of animals including River otters, monkeys, birds, and capybaras. We loved our guide Luis and all the people we met. The food was delicious and locally grown and there was never a dull moment. Would highly recommend! Read all


I went to Posada as part of a wider group trip, so did not pay for it directly. The lodge feels very far from anywhere and yet it feels incredibly safe. The rooms are open to nature, but nothing was ever damaged (use the safe boxes as advised, especially for food - not that you'll need any - the catering is excellent, with plenty of vegetarian options, and snacks are also provided between meals). There are flushing toilets, incredible shower facilities and the beds are very comfortable with mosquito nets placed at night by the staff. Drinking water vats are strategicvally placed throughout the lodge but you may have a long-ish walk to the common areas through corridors. Some parts of the corridors are open to the elements, but umbrellas are provided everywhere in case of rain. There is obviously no air conditioning, but this helps you acclimatise. The lodge is run by a family and others from the Infierno community, which gives the place a homely feel, with resident tour guides and a local geologist for citizen science projects. Massage services are available and there is a local shop for souvenirs and essentials like bug spray, clothing and torches. Tons of activities can be arranged, but it's also nice to relax in the hammocks and common areas and listen to the sounds of nature. While this hotel is not going to be for everyone, I had the most incredible time! Read all


The place to go if you want to see Macaws in the Peruvian rainforest. We stayed at the Tambopata Reaearch Centre (TRC) for three days and had Juan Carlos Yatto as our guide for the duration of our stay. We loved the mission of the TRC ie Macaw conservation and the link between Macaw nest site availability and the overall health of the rainforest. Juan Carlos Yatto (there is another JC at the research centre) was a fantastic guide and really made a difference to our experience at the TRC. His knowledge of the different species of wildlife and plants was amazing, his ability to spot things in the day or at night was phenomenal and he really made things accessible for our group. His English is excellent (including great humour when appropriate) and is a super guy. I really do recommend the TRC abd Juan Carlos Yatto as a guide. We saw an abundance of wildlife of all descriptions thanks to him and learned a huge amount without being overloaded. Read all


Two planes, a bus and a boat…that’s how we made it to TRC, and every minute was worth it. Tambopata is a jewel, from the moment you are greeted by the guide assigned to you (Juan Carlos Gonzales for us) to the last boat ride back to civilization. Juan Carlos was amazing…on just one hike he found five of the seven species of monkeys in the area! He is truly an expert..can hear, see and even SMELL animals, birds and insects to point out to us. We upgraded to a deluxe suite and it was decadent! An elegant outdoor tub and shower on a private balcony was soo nice’ Although we went in the rainy season, it never rained while on a hike or excursion. It rained for a few minutes on our late afternoon cruise , but not enough to dampen our enthusiasm, or prevent us from seeing a capybara in the mid! (And despite the warning of a lot of mosquitoes, I have been bitten more in my own back yard!) The bar is great, there’s PLENTY of food…we are going home feeling so lucky to have had such a great connection to the beauty of the Amazon. Read all


We had a fantastic time for our 3N/4D stay at Tambopata Research Center. The whole experience was marvellous. Rooms and facilities were great and meals superb. The Staff, ably led by Tanya the manager, were all friendly and helpful. This is the only lodge actually inside the Tambopata National Park, and we enjoyed being so "remote". I like that you have one guide who coordinates and takes you on all your activities; Jair our guide was amazing. One morning our planned activity was rained out, and I liked that they have alternative "wet weather" activities planned. There are lectures each night by researchers, which were very interesting. Also citizen science projects that you can participate in. All up, it was a fantastic way to experience the Peruvian Amazon. Read all


Posada Amazonas by Rainforest Expeditions is an extraordinary place. From your arrival at the airport in Puerto Maldonado all the staff is always attentive to your needs. You travel by boat to the hotel Posada Amazonas and it is a unique experience. It really is a total disconnection and a recollection with Mother Nature 🌎 The buffet lunch is delicious (already included in the price). You have a guide who speaks Spanish and English at all times and accompanies you to explore the jungle, the river and other activities. The price is worth it. Outside my room I caught a glimpse of monkeys :) The night sky is starry and very spectacular ✨️ 5 star service. I will definitely come back. Read all


I stayed with my parents at Refugio Amazonas for 3 days. We really enjoyed our stay and had a wonderful time here. The staff were extremely kind and well informed. The lodge manager- Arturo in particular was very helpful. To highlight their culture: They prepared special vegetarian meals for my parents, always ensured we felt comfortable and all our needs were met. A stay here is a must do to get a real feel of the Amazon rainforest on your trip to Peru! Noteworthy details: There are a lot of activities for kids and families to do, but my personal favourites are: Macaw Claylick, OxBow river ride, sunset cruise and the canopy tower. Read all


I can't express how amazing our guides were. Incredibly knowledgeable and able to spot birds, frogs, spiders, animals, etc. with an almost unbelievable ability. The research and contributions to the jungle they are making at the Center are to be commended. The facilities were nice and kept clean and the staff was great, but between the walls in the rooms being open to the jungle, the heat, the bugs, underpowered fans, having to completely cover up for hikes due to bugs and then getting overheated, etc. it made for a tough stay. The food was good but after a couple days became repetitive. I would recommend this for serious birders who are willing to endure a bit for an incredible adventure. Read all
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