Male poison arrow frog (Dendrobates macero) by pbertner on Flickr.

Walking around at 4:30 in the morning has its advantages. This beautiful frog was found calling from an elevated perch on a fern. Relatively common, I saw several of these whenever I passed riparians on the trail. Found during a night hike in Pantiacolla midlevel rainforest, Manu national park, Peru.

Green and Black Poison Dart Frog

Dendrobates auratus (Dendrobatidae), the Green and Black Poison Frog, is a diurnal terrestrial frog from Central America and adjacent South America, with toxic skin secretions that contain many alkaloids.

These alkaloids are diet-derived, with ants and mites being the main sources of toxic compounds identified so far. Alkaloidal skin secretions are thought to protect these frogs from predation, and also their aposematic coloration (warning coloration). 

However, the coloration of Dendrobates auratus does not protect so much  the frog of one of their predators, a theraphosid spider, the Panama red rump tarantula (Sericopelma rubronitens), as this spider is a non-visual hunter who uses substrate vibrations to detect potential preys, and uses its chemoreceptors on its legs and pedipalps to “taste” the frog. It seems that    the Panama red rump tarantulas reject distasteful frogs only when they produce high amounts of skin secretions. So in the case of S. rubronitens, the bold green and brown patterns of D. auratus are unlikely to serve as a warning of distastefulness. 

Reference: [1]

Photo credit: ©Mike Graziano | Locality: Oahu, Hawai’i


Lehmann’s Poison Frog (Oophaga lehmanni)

Also known as the Red-banded Poison Dart Frog, Lehmann’s Poison Frog is a species of poison dart frog native to Colombia. Like most South American frogs this species is highly poisonous and its bright red or yellow coloration is used as a warning signal to potential predators. Sadly like most amphibians this species is critically endangered as habitat loss has caused their populations to drop drastically.



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Cannibal-Style Parenting

It may be an act of care, not sacrifice, when a male dyeing poison frog (Dendrobates tinctorius) leaves his newborn in water inhabited by larger, cannibalistic tadpoles. That’s the conclusion of a new study in which researchers observed the behavior of the 2-inch-long dyeing poison frogs around pools of water in French Guiana. When tadpoles hatch out of eggs, fathers carry their new offspring—one or two at a time stuck on their back—to small pools of water that have collected in plants or tree trunks, where the tadpoles are left alone to mature. Researchers found that while pool size and depth had little bearing on whether tadpoles were dropped off, the fathers were most likely to leave their newborns in pools that already housed larger, more mature tadpoles known to cannibalize smaller tadpoles. It may be dangerous for the newcomers, but it also indicates that the pool has the proper conditions for a frog to grow, the researchers hypothesize in the journal Behavioral Ecology and Sociobiology. In the natural pools observed, holding about 50 tadpoles at any given time, only 12 acts of cannibalism were observed during the study period, suggesting that many tadpoles make it to maturity without being eaten. More work will help researchers understand how the counterintuitive behavior has evolved and how pressure on habitats may have played a role.


| image by Bibiana Rojas