Changing Planet

Science and Magic From a Giant Amazon Treefrog

Skin secretions collected from the Waxy Monkey Treefrog (Phyllomedusa bicolor) are used by the Matsés Indians of Peru for ‘hunter magic’–the secretions are burned into skin of humans, resulting in vomiting, passing out, then waking a few hours later to ‘feel like a god,’ ready to hunt! These indigenous people of the Amazon ‘milk’ the frogs to collect a cocktail of peptide chemicals known as ‘sapo.’

Such nonlethal secretion collection can yield new insights into frog skin chemistry, for example, sugar was found this year in tropical poison frogs that had been studied for over 50 years by using a different approach to collect everything that oozes from skin glands. More recently, secretions collected specifically from the leg (tibial) glands of the Waxy Monkey Treefrog yielded additional peptides and encoding DNA not previously detected from glands on the head (the parotid glands). The difference in the peptides secreted from glands on the legs versus glands on the head may be to ‘deal with rearguard predators or may indicate that the tibial glands have arisen more recently in the evolution of the species and have yet to express the full spectrum of peptides from the parotids,’ said study co-author Professor Chris Shaw from the School of Pharmacy, Queen’s University in Belfast. These findings were published as ‘Molecular cloning of skin peptide precursor-encoding cDNAs from tibial gland secretion of the Giant Monkey Frog, Phyllomedusa bicolor (Hylidae, Anura)’ in the scientific journal Peptides.

One type of peptides from this group of frogs, the dermorphins, were recently exposed in the New York Times as being illegally used in horses so that they could race faster with no pain. Dermorphins are 40 times more powerful than the pain-killer morphine, and such components of ‘sapo’ contribute to the Matsés heightened senses and abilities to run quickly without pain, making them better hunters. In the gallery above, explore more about these frogs including secretion collection by our team and Matsés peoples from Peruvian Amazon rainforests. Learn more about forests from around the world via the Indigenous Forest Research Organization for Global Sustainability (i.F.r.o.g.s.).

Watch the Matsés collecting process below.

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After earning her Ph.D. on the "Chemistry of Amphibian Skin Secretions," Dr. Valerie C. Clark founded the conservation organization i.F.r.o.g.s. (Indigenous Forest Research Organization for Global Sustainability) 501(c)(3). i.F.r.o.g.s. engages the public online to explore Earth’s biodiversity and is active on the ground in Madagascar with local people to survey biodiversity and protect and restore rain forests. Her scientific expeditions have been supported by the National Geographic Society since 2007. Her publications are available for free at
  • mahdi

    its som thing unbelivable

  • Dan

    I’m curious as to why the plight of the frog, who is obviously being terrorized during this process, is entirely ignored.

  • Douglas Argetta

    Sapo means frog in Spanish by the way

  • Amosis

    I wonder how the tribesmen would like to be strung up like that.

  • Nayan


  • Mike Oregon

    When are going to stop exploding animals? I cannot wait to see what big corporations are going to do with this new niche… Thanks, Mr. National Geographic for giving them new ideas…

  • Don Ivey

    Ive heard this drug lets them “see”better for hunting, this looks cruel but I bet they release it unharmed, just stressed out.

  • Amazon Explorer

    Hola people:

    We are from Amazon Explorer, we organize expeditions to the Matsés tribe. This is just to say that the indigenous shaman milk the frog and they release it unharmed. They just stress out the frog in order to the animal produce toxins.


    Hector Vezirian
    Amazon Explorer
    Iquitos, Amazon River, Peru (South America).

  • Marc Anthony

    Do u realize there isn’t walmart where this gentleman lives princess? Before you go feeling sad for the frog

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