Amphibians of the Peruvian Amazon

Frogs, toads, and other amphibians inhabit the forests of the Peruvian Amazon, often hidden among the vegetation, beneath fallen leaves, or near streams and rivers. Some are tiny and difficult to spot, while others display striking colors or remarkable survival strategies.

Since my first trip to the San Martín region, I have been fascinated by poison dart frogs, these small yet extraordinary creatures with spectacular colors.

This page brings together my encounters with the amphibians of the Amazon rainforest in this region of Peru. Each species is an opportunity to discover a discreet and often overlooked world that plays a vital role in the balance of the ecosystem.

You can also explore my other articles featuring the species I have encountered, including birds and insects, by clicking here.

If there is a particular species you would like me to feature, feel free to let me know in the comments. I’ll be happy to look for it during my next field outings—provided it can be found in the region, of course.

Ranitomeya Summersi nominal

Identification

I’m going to start this challenge with one of my favourite subjects: amphibians. And not just any amphibian, but a dendrobatid endemic to the San Martín region: the nominal Ranitomeya summersi.

This 2 cm frog is the “nominal” form, in other words, the “true” one, as there are several mimics, such as R. summersi white banded, which I was lucky enough to see on the same day and will have the opportunity to introduce to you later. (You can click here to read my article dedicated to the dendrobatids I encountered in the San Martín region in 2025.)

It can first be identified by its location, and then by its colours and patterns. It is a black frog with highly saturated orange markings that warn of its toxicity. This individual caught our attention because its colours were tending towards white, making it look like its mimic. However, my friend and guide Warren confirmed its identification, notably using another identification method: listening to its call.

My encounter

It was early when I went for a walk in Alto Shilcayo. The temperatures were still cool, which is a particularly good time to encounter many species as they begin to wake up. My friends were ready, so we started walking. After just five minutes, we saw our first frog. One of my friends recognised its call, and its orange colours gave it away among the vegetation at the foot of a tree.

Being in the selva is always spectacular. Between the cliffs and the vegetation, you feel incredibly small. But when you see a dendrobatid measuring just 2 to 5 cm, it is hard to imagine how it experiences the world within this immense landscape.

Its habitat and lifestyle

This dendrobatid is endemic to the San Martín region of Peru. It lives in the selva, in the dense Amazonian rainforest, where vegetation and humidity are everywhere. It can sometimes be found on rocks covered with bromeliads or at the foot of large trees such as ficus.

Reproduction

Dendrobatids generally lay their eggs in small water reservoirs called phytotelmata. These are usually found at the base of large leaves that collect rainwater. Some species can also lay their eggs directly on leaves, but this is not the case for R. summersi.

What are its main prey and predators?

It mainly feeds on small flies, such as fruit flies (Drosophila), which come to feed on fungi.

It is part of a larger food cycle, as it is also preyed upon by snakes and birds. But the selection pressures affecting dendrobatids do not stop there: tadpoles can also eat one another.

Is this species threatened?

To find out whether a species is considered threatened, we can refer to the IUCN (International Union for Conservation of Nature). Unfortunately, this species is classified as threatened: https://www.iucnredlist.org/species/193430/89224207

This is why it is extremely important to avoid handling them, especially without some knowledge of amphibians, which are highly sensitive animals.

References

• IUCN (International Union for Conservation of Nature)
• Aposematic Poison Frogs (Dendrobatidae) of Andean Countries: Bolivia, Colombia, Ecuador, Perú and Venezuela

Ranitomeya Summersi white banded morph

My encounter

To avoid repeating the same information, I won’t go over everything I have already explained about the nominal R. summersi.

We had a little more trouble finding this individual. We had to walk further into the reserve near Tarapoto, in an area my friends know well because they have installed a system to help dendrobatids reproduce. This raises an important question: what long-term impact do we have when we try to help a species threatened with extinction?

I really like this species because of its colours, but also because of what I discovered later, while spending time on my computer looking through my photographs after our outings. This particular individual especially touched me when I zoomed in on its head to make sure I had focused correctly. As you can see below, it gave me a lovely little smile! How could I resist…

Is this species threatened?

This species is also threatened with extinction. This time, I wanted to focus on the causes. There are three major ones:

• Climate change: something that no longer needs to be demonstrated.
• Deforestation, which is still a major issue in the San Martín region, particularly the expansion of oil palm monocultures. These destroy the soil and leave these species, as well as many others, with no suitable habitat in which to reproduce in their phytotelmata. This is why some nature lovers are working to find solutions to help them.
• Illegal collection from the wild, although its extent is difficult to quantify, particularly for the exotic pet trade. Fortunately, some countries, such as France, require owners of dendrobatids kept in terrariums to provide documentation proving their legal origin.

Hyloxalus nexipus

Identification

This is one of the most common dendrobatids here. It can be found near bodies of water, usually where there is some current. Its colours vary slightly, from yellow to red in the stripes, while the rest of the body ranges from lighter to darker blackish brown. The legs have slightly bluish-grey patterns. I am not sure whether this is a general characteristic, but I have noticed that some darker males seemed to attract lighter-coloured females.

This dendrobatid measures between 20 and 23 mm, with the female being slightly smaller than the male.

My encounter

There were plenty of them that morning. The air was humid, which they seem to love. I could hear the males calling to attract females. There were really more than usual: I counted nearly ten of them, and they seemed to pay even less attention to me than they normally do… Given their small size, you really have to watch where you step, especially when they come within a few centimetres of my camera bag.

I stayed for almost an hour. The passing of a bird and a morpho butterfly added some variety to my discoveries. I was able to take my time photographing several individuals, and it was easy to notice that their patterns and colours are unique to each one.

Its habitat and lifestyle

As I mentioned, this is one of the most common species here. It lives in humid areas of the Amazon, especially among rocks (exactly where I find it, along the banks of the Shilcayo River), or near waterfalls. It is thought to occur from northern Peru to Ecuador.

As is generally the case with dendrobatids, the male takes care of the tadpoles after they hatch. The tadpoles attach themselves to the mucus covering his back, allowing him to transport them to a safe place where there is enough water and nutrients.