Darwin's frog, also known as the southern Darwin's frog, is a small amphibian native to South America that became world famous after it was mentioned in Darwin's writings. In their natural habitat, these frogs can be difficult to observe, as they are usually able to hide easily thanks to their leafy appearance.
If you want to know more about one of the most intriguing species of frogs in the world, we invite you to continue reading this PlanetAnimal sheet, in which you will find useful information on the origin , physical appearance, breeding, diet, and protection status of Darwin's frog.
Origin
- America
- Argentina
- Chile
Origin of Darwin's frog
Darwin's frog (Rhinoderma darwinii) is a small amphibian endemic to Argentina and Chile, which lives mainly in the temperate forests of the Patagonian region. This species adapts perfectly to humid and arboreal regions whose altitude varies between 15 and 1800 meters above sea level, and has a preference for mature primary forests with a complex structure.
In Argentina, individuals of this species are only present in the regions bordering Chile. We can observe their presence in the Nahuel Huapi and Lanín national parks, located between the provinces of Río Negro and Neuquén.In Chile, we find Darwin's frog from the city of Concepción to Aysén, respectively located in regions VIII and XI.
Its name is a tribute to the great English naturalist and biologist Charles Darwin, who was the first to portray this species during his famous travels in South America, devoting a few lines to it in his book “Le voyage of the Beagle”.
Characteristics of Darwin's Frog
Darwin's frog is characterized by a rounded body, a triangular head with a pointed snout and a cylindrical nasal appendage. Females are generally slightly larger, measuring between 2.5 and 3.5 cm when fully grown, while males hardly exceed 2.8 cm. Likewise, the size of these frogs can vary depending on the climate of their habitat, with the largest specimens tending to live in regions with more marked seasons.
Their limbs are relatively long and thin compared to the rest of their body. The forelegs do not have flippers between the fingers, while for the hind legs, the flippers are only present on the first three fingers.The skin on its back is slightly grainy and has side folds, it can have varying hues ranging from bright green to shades of coffee brown. On the ventral area, the black background is predominant with white spots, a pattern that could characterize an aposematic coloration to alert and scare away predators.
In Chile, there is another species of frog, called Rhinoderma rufum and popularly known as Chilean Darwin's frog or northern Darwin's frog, which is very similar to Darwin's frog (southern ). Unfortunately, this small Chilean frog is considered an extinct species, as it has not been officially recorded in its natural environment since 1978.
Behaviour of Darwin's frog
Thanks to the shape and color of its body, Darwin's frog can camouflage itself quite easily among the leaves of the immense Patagonian forests, thus deterring many of its predators.Despite this, this small amphibian faces several predators in its natural habitat, such as rodents, birds, and snakes. Also, when its camouflage technique cannot be used or is not effective, and the frog comes face to face with a predator, it usually leaps back and drops onto its back, showing the peculiar pattern of his stomach. This behavior is one of the pieces of evidence leading experts to believe it is aposematic pigmentation to alert and scare away predators.
Regarding its diet, it is a carnivorous animal, whose diet is based mainly on the consumption of insects, snails, spiders, worms and small invertebrates so general. To hunt, Darwin's frogs tend to use their long, sticky tongues strategically to catch prey, while remaining "camouflaged" among the leaves of primary forests or swampy areas.
One of the most curious aspects of Darwin's frog behavior is its call, which produces a very high-pitched sound, similar to that of some birds. To the human ear, this sound may sound like the whistling of cowboys in the meadows, so this cute little frog is also known as the "cowboy frog" in its native countries.
Reproduction of Darwin's frog
The reproduction of Darwin's frog is a unique phenomenon in the world of amphibians, which is characterized by a particular form of incubation called "neomelia" . During the breeding season, males and females meet and perform a sort of short, gentle nuptial embrace called amplexus. At the end of this embrace, the female lays on the ground between 3 and 30 small eggs, which generally do not exceed 4 mm in diameter. About 15 days after the amplexus, the embryos already make their first movements, and it is then that the male introduces them into his mouth so that they reach the vocal sac located in his throat.
Inside the male's vocal sac, tadpoles typically complete their development in the spring or fall. After about six to eight weeks, the tiny frogs are "expelled" from their parent's vocal sac through an opening under the tongue. From this moment, they are ready to jump and adapt to earthly life, as their parents do.
Darwin's Frog breeding seasons are irregular, and can occur throughout the year. However, this particular type of incubation they perform is usually favored by the heat of summer, so they usually occur between December and March
Darwin's frog protection status
Are you wondering if Darwin's frog is in danger of extinction? Currently, Darwin's frog is an endangered species, being classified as "endangered" on the Red List of Threatened Species, compiled by the IUCN (International Union for Conservation of Nature).
The rapid and worrying decrease in its population is mainly due to the fact that, for several years, primary forests have been degraded to make way for agricultural and livestock areas. In addition to deforestation, Darwin's frogs seem particularly susceptible to an infectious disease called chytridiomycosis, which affects several species of amphibians and is caused by a fungus of the genus Chytridiomycota.
The "Darwin's Frog Binational Conservation Strategy" is an important initiative which, as its name suggests, aims to h alt the destruction of Darwin's frog habitat, prevent its hunting or capturing it and to raise awareness of its essential role in the balance of South American ecosystems.
References- Crump, M. L. (2002) Natural history of Darwin's frog Rhinoderma darwinii. Herpetological Natural History 9, pp.21-31.
- Formas, R. et al (1975) La identidad del batracio chileno Heminectes rufus Philippi, 1902. Physis 34: pp.147-157
- Cei, J. M. (1962) Batracios de Chile. Publications of the Universidad de Chile. Santiago, Chile. pp.180.
- Burger C. (1905) Rhinoderma darwini neomelia. D&B. Imprenta Cervantes, Santiago de Chile. pp.23
- IUCN Red List of Threatened Species. The IUCN Red List of Threatened Species.
- Cunningham, Andrew A.; Barrientos, Carlos; Ortiz, Juan Carlos; Busse, Klaus; Clarke, Barry T.; Valenzuela-Sánchez, Andrés; Soto-Azat, Claudio (2013). Is Chytridiomycosis Driving Darwin's Frogs to Extinction? PLOS ONE 8 (11).
Darwin's Frog Pictures
