Darwin’s frog

703px-Rhinoderma_darwinii

Profile

Darwin’s frogs are small amphibians living in southern South America. These frogs, as you may have already guessed, are named after Charles Darwin, who discovered them. Although the individual shown above is brown, not all are this color. They can sometimes be bright green, or be a mix of brown and green. The underside, which is not shown in this picture, is brown, black, and white with large blotches. One benefit these frogs have from being these colors is camouflage. If a predator comes by, they just need to stay really still, and they will look like a leaf. Either a dead leaf if they are brown or a live leaf if they are green. One distinctive feature of the Darwin’s frog is the fleshy proboscis extending from the tip of their nose. It is partially hidden by the plant in the picture above, but you can probably see the small, brown tube on the end of its nose.

Size

Darwin’s frogs are actually a lot smaller than they might look. Males can be from 0.9 to 1.1 inches (2.2-2.8 cm) long. This is the body length, not including the legs. Females are slightly larger, averaging from 1 to 1.2 inches (2.5 to 3.1 cm) long. They do not weigh very much either. Adults weigh somewhere around just 0.14 ounces (4 g).

Diet

Like many other frogs and toads, the Darwin’s frog is a sit-and-wait predator. This means that it does not hunt down its prey, but instead, well, sits and waits for its next meal to come by. They feed mostly on insects and other small invertebrates. These may include worms, snails, and spiders. When they spot some food that comes by, they will lunge forward, capture the prey with their sticky tongue, and enjoy a nice meal.

Habitat and range

Unlike most of the frogs I have talked about that live in South America, the Darwin’s frog does not live in the Amazon rain forest. Instead, it lives in the southern half of this continent. The two countries they live in are Chile and Argentina. It is more abundant in Chile than in Argentina. Because they are frogs, these animals live near water. This may take the form of puddles, ponds, bogs, streams, or rivers. Regardless of the water source, Darwin’s frogs do like to live in forests. This helps them be camouflaged against the leaf litter on the forest floor.

Status and threats

The Darwin’s frog is classified as ‘Vulnerable’ on the IUCN Redlist. In some areas, specifically in Chile, the Darwin’s frogs are known to be declining due to deforestation. Sometimes native trees are replaced with trees from other countries, such as pines or eucalyptus. In other places besides Chile, the main cause for the decline in population of these animals is unknown. In these areas, disease is thought to be a possible reason for the decrease of the Darwin’s frog.

Mating, eggs, and young

Male Darwin’s frogs call year round, but they increase their calls during the mating season, which lasts from November to March. When a male finds a willing female, he will lead her to a sheltered area where the female lays her eggs. The male then fertilizes them and the female leaves. The eggs will stay in the care of the male for the next 20 days until something amazing happens. At this time, the tadpoles are wriggling around in their eggs, but they do not hatch yet. Instead, the male picks the eggs up and swallows them! At least it looks like he does. What he actually does once the eggs are in his mouth is slide them into his vocal sac! The eggs then hatch, and the tadpoles spend their time inside their father. His internal organs distort to allow room for his many children, making him look fat.

Once the young have mostly finished metamorphosis, reaching the length of about 0.4 inches (1 cm), they finally come out. This may take up to 50 days! They hop out of his mouth, or he spits them out, to get their first glimpse of the outside world. To watch a video of this amazing procedure, click here. In the wild, Darwin’s frogs can live up to 15 years.

Don’t forget to scroll down and comment your guess about what the next animal is!

brown snake

Sources:

Photo Credits:

  • Darwin’s frog – Mono Andes
  • Mystery animal – Thomas Brown

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