Drawin’s Frog (Rhinoderma darwinii)

Darwins-frog-side-profile

  • Name: Darwin’s Frog
  • Latin: Rhinoderma darwinii
  • Classification: Amphibian
  • Origin: Chile
  • Lifespan: Up to 16 years

Taxonomy

Kingdom: Animalia (Animals)
Phylum: Chordata (Vertebrates)
Class: Amphibia (Amphibians)
Order: Anura (Frogs)
Family: Rhinodermatidae (Native to South America)
Genus: Rhinoderma (Native to South America)
Species: Rhinoderma Darwinii (Darwin’s Frog)

Apperance

Length: 2.5-3.5cm
Weight: 2 grams

The Darwin’s frog is covered in moist skin which is usually brown or green. Its front feet are not webbed like other frogs but the toes on its back feet sometimes are. The male of this species has an enlarged vocal sac in which it rears its young.

Relative

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  • African clawed frog (Xenopus laevis) -LEAST CONCERN-
  • Mexican tree frog (Smilisca baudinii) -LEAST CONCERN-
  • Cane toad (Rhinella marina) -LEAST CONCERN-
  • Pig frog (Rana grylio) -LEAST CONCERN-

Habitat & Distribution

The Darwin’s frog tends to stay in areas near cool and shallow creeks or streams. It can be found in Latin American countries such as Chile and Argentina.

Map of distribution of the Darwin's frog
Map of distribution of the Darwin’s frog

Diet

The diet of the Darwin’s frog consists mainly of insects and other small invertebrate. It catches its prey by remaining motionless, waiting for unsuspecting bugs to crawl or fly past, the frog then lunges forward, catching the prey in its mouth.

Behaviour

The Darwin’s frog is most active during the day, spending many hours basking in the warm sunlight while remaining camouflaged in the surrounding leaf litter.

It also spends its day waiting for prey. It hides among the damp leaves and waits patiently for insects to wander by, it then leaps forward devouring the prey.

When threatened, the Darwin’s frog will play dead by rolling over onto its back until the danger has passed. Sometimes, it will leap into a nearby stream and float on the water on its back, again feigning death.

When rearing young, the male Darwin’s frog will take a spawn of newly hatched tadpoles into its mouth and move them into its enlarged vocal sac, which will temporarily be used as a nursery. The tadpoles are sustained by eating the remainders of their eggs and by nutrient-rich secretions by the adult. When they have grown into froglets, they are spat out from the vocal sac. A male Darwin’s frog can look after up to 19 froglets at one time.

Reproduction

The male Darwin’s frog sings throughout the breeding season, which lasts from November through to March, to attract a mate. Once a mate is found, the male will lead the female to a sheltered area where courtship and egg laying take place. The female will then leave but the male will remain with the eggs, guarding them while they develop.

After about 20 days, the tadpoles will begin to wriggle inside their shells. The male then uses its tongue to pick them up and move them to its enlarges vocal sac, which will act as a nursery for the time being. The tadpoles attain sustenance by eating the remains of its eggs and through the nutrient-rich secretions provided by the adult.

Once the tadpoles have grown to a length of 1cm, it would have grown two pairs of legs and its tail would be reduced to a stump, they are then spat out by the male. Up to 19 can be cared for at one time by an adult male.

Juvenile Darwin's frog
Juvenile Darwin’s frog

Adaptations

  1. The male Darwin’s frog raises his young in his mouth. He holds them as eggs and when they hatch, he transports them to a water source.
  2. The Darwin’s frog has excellent camouflage as it has evolved to resemble a leaf. It blends in remarkably well with the leaf litter in which it lives. This reduces the risk of predation.
  3. Like other frogs, the Darwin’s frog has webbed feet that help it manoeuvre through water.
  4. The Darwin’s frog has eyes and nostrils on the top of its head allowing it to stay almost submerged underwater.

Threats

There is a worrying decline in the number of Darwin’s frogs throughout the world, especially in Chile where some populations are disappearing entirely. This is because of deforestation and the replacement of their native trees with exotic species.

In other regions, the causes are unknown, but it maybe be down to climate change and ultraviolet radiation. This could also be what is contributing to the worldwide decline in amphibians.

Conservation

IUCN Status: Vulnerable

Throughout the Darwin’s frogs range, there are a number of protected areas helping to preserve its habitat. However, these need to be improved and expanded, especially in sites near the north of its territory.

Fun Facts

Male: Male frog
Female: Female frog
Young: Tadpole

Group: Army

The Darwin’s frog is named after Charles Darwin, who discovered it during his world voyage.
The males call is small and bell-like, despite its large vocal sac.
It is also known as the Darwin’s toad and the Cowboy frog.

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