There have been a total of 149 species of glass frogs so far discovered, with 14 species found in Costa Rica. The most recent of these was discovered only in 2015 and are notable for their translucent skin. With the scientific name Centrolenidae, glass frogs are an unusual and fascinatingly exotic species that can be found in Central and South America as well as in southern parts of Mexico.
This intriguing species was first discovered in the 1920s, and since they are small and hard to capture, let alone see, more species may still be found. Let’s look at some common questions people have about these extraordinary frogs.
1. Where can the glass frog be found in Costa Rica?
Hidden away in the Cordillera de Talamanca mountain range in the southeastern half of Costa Rica, the Hyalinobatrachium dianae glass frog eluded scientists for decades before being discovered in 2015. This is less surprising because this species of frog is nocturnal, normally avoiding daylight when they search for prey.
Talamanca is mostly covered in rainforests which is ideal habitat for glass frogs. They very slowly climb high in the trees to help them evade predators during the dry season. When the rainy season arrives, usually in May, they climb back down the tree in order to mate.
Other areas where glass frogs might be found include the Heredia and Limón Provinces, to the north and west of San José. They thrive in rainforest areas near mountain streams that are necessary for their tadpole offspring to grow into adult frogs.
2. What does a glass frog eat?
Glass frogs mainly prey on insects, and even other frogs if they are small enough. They are carnivores, so will eat anything small enough to fit in their mouth, and this can also include flies, bugs, crickets, moths, ants, and spiders.
3. Do glass frogs glow?
The slope snouted glass frog (Cochranella euknemos) which can be found in Costa Rica, has yellow spots on its back. These yellow spots act as camouflage to mimic spots of sunlight streaming through the forest canopy. These yellow spots also glow in the dark.
4. Do glass frogs have teeth?
Most species of frogs have teeth in their upper jaw. These small teeth are cone-shaped and are not used for chewing their prey. Instead, the teeth help the frog hold on to an animal they have caught, so that they can swallow it without it escaping.
5. Why is their skin see-through?
Glass frogs are normally lime green when you look at them from above, and it is only their underside that is transparent. This is when you can see their internal organs, and their heart beating if you look very closely as the frogs are tiny.
Scientists aren’t really sure why it is possible to see these frogs’ internal organs. It is thought that it aids in camouflaging the frog to some extent as the outline of the frog more easily blends in with its surroundings. Though not every type of glass frog has see-through skin, those that do are slightly more difficult to see by predators.
6. What predators eat glass frogs?
During the mating season, when the frogs return to ground level to be close to water, they can be eaten by small mammals and lizards. They can fall prey to birds whether they’re on the ground or in the trees. Snakes are the biggest risk when they are in the trees, as well as any other animals that climb.
When a glass frog lays eggs, there is a risk from wasps. Male glass frogs guard the eggs, and when a wasp lands to eat an egg, the male frog will kick the wasp away.
Frog flies are another problem because they like to lay their eggs within a clutch of glass frogs’ eggs. When the fly’s eggs hatch, these maggots will eat the frog’s eggs.
When the tadpoles emerge from the eggs, they are at risk from fish and birds. They could also be eaten by beetles and the larvae from dragonflies.
7. How far can glass frogs jump?
While glass frogs try to avoid predators by climbing high in the trees, if they are faced with predators, they can jump a considerable distance. They can typically jump 10 feet or 3 meters to avoid ending up on a predator’s lunch menu.
8. Are glass frogs endangered?
Out of the 149 species currently discovered, 36 are endangered. While these frogs have many predators, the biggest risk to their extinction is their loss of habitat.
Rainforests are cut down for agricultural purposes, and species can be lost in the process. There are campaigns in Costa Rica as well as other countries to protect these habitats before they are lost and the frogs along with them.
9. What size are glass frogs?
This species of frog is very small, with an adult measuring from about an inch or 2.5 cm in length. They can be as big as 3 inches or 2.5 cm.
They don’t weigh very much either, with adults weighing between 0.2 and 0.5 ounces (5 to 14 grams).
10. Do grass frogs croak?
Different frog species make different sounds, and it is only the male that croaks. This happens because they have a small sack in their throat that they use to vibrate the air. But the glass frog doesn’t croak, instead, making a high-pitched whistle to attract females.
11. Where are their eggs laid?
While most frogs lay their eggs in water, glass frogs are a little different. The female frog lays the eggs on the underside of a leaf overhanging a stream. The male then fertilizes these eggs and guards them until they hatch. This species typically has 18 to 30 eggs in each litter.
When they hatch, the tadpoles will fall into the stream below. It can take 12 to 14 weeks for each tadpole to develop into a fully grown adult.
12. How long do glass frogs live?
If a glass frog manages to avoid predators and habitat loss to reach adulthood, it can live between 10 and 14 years.