5 Vietnamese Mossy Frog Facts: The Camouflage Master

‘Tonkin bug-eyed frog’ and ‘Vietnamese mossy frog’ are other names for ‘mossy frog.’ The species belong to the Rhacophoridae family of bush frogs. This frog is excellent at deception and camouflage. Here are some fun facts about one of our strangest frogs.

Vietnamese mossy frog
Scientific name: Theloderma corticale
Phylum: Chordata
Class: Amphibia
Order: Anura

1. Vietnamese mossy frogs are masters of camouflage 

Many amphibian and reptile creatures have colors that enable them to hide in their environments. A few own textured skins to make them look invisible in their surroundings. And the Vietnamese mossy frog has the best of both worlds. It is one of the animals having the most complex camouflage patterns in the animal kingdom.

While the other frogs have smooth skin, the Vietnamese mossy frog features rugged and uneven skin with many lumps and spikes. It’s like a frog with plenty of warts growing. The species come with a mix of various colors of green, red, brownish-black to black spots.

Vietnamese Mossy Frog looks like a moss

The skin coloring paired with the texture makes Vietnamese mossy frogs look like moss or lichen. That’s one of many reasons why people call it that name. You can barely recognize them in the surroundings that are full of moss. Their eyes are even designed to help them camouflage. There’s a dark stripe running through the pupil breaking up the dazzling green iris.

This frog doesn’t need to do anything, just stays motionless and it has flawless camouflage. They pretend to be a clump of moss most of the time, only display their eyes while watching the surroundings.

You may read some of the other Best camouflage creatures in the world:

  1. Cuttles
  2. Chameleon
  3. Eastern screech owl
  4. Stonefish
  5. Arctic fox

And if that was not enough, the Vietnamese mossy frog has another way to protect itself. When scared, they will curl up and play dead, hoping their predators (usually a tree-dwelling animal or snake) will stop and go away.

Mossy frog curls up into a ball to play dead.

About the size, these frogs can reach lengths of 3.5 inches (8.8 cm). Like many frogs, male Vietnamese mossy frogs are 20% smaller than the female counterparts. They have shorter bodies and thinner rear leg bones than females. When a male frog reaches sexual maturity, he develops nuptial pads that are pink or red on his front legs.

When Mossy Frogs are resting peacefully, they flatten out, making their length and width look equal. In this position, they practically vanish into moss-covered rocks. This adaption is an efficient strategy to escape from predators or stealthily monitor for prey.

The Vietnamese mossy frog also has adhesive disks on each toe, which enables the tiny creature in climbing. The males have a prominent reproductive callus at the base of the inner finger.

All of those incredible abilities above have allowed the Vietnamese mossy frog to live in a place where predators lurk around every turn.

2. Vietnamese Mossy Frog habitat

Vietnamese Mossy Frogs are native to Vietnam, notably in the country’s northern regions. Aside from being a camouflage master, the frog is also a good adaptive animal. They are semi-aquatic, which means they can live beneath rocks, among mossy plants, and in damp caverns. Those are ideal places for the mossy frog to easily blend in.

Their natural environment includes evergreen tropical or montane rainforests and woods. They are found at an average elevation of 3,000 feet above sea level! This indicates that these frogs are adapted to a much cooler environment and barely at temperatures above 75°F (23oC).  

There is no evidence indicating whether these frogs are poisonous or not.

In the wild, the Vietnamese mossy frog’s lifespan is still a mystery. In capacity, it can live as long as 12-15 years.

Despite habitat destruction and a grim future for the world’s frogs overall, the mossy frog is still well so far. However, it has been designated as ‘of least concern’ at the endangered level, yet its population is declining.

3. Mossy frog calls

Although it may be difficult to see a mossy frog since its camouflage is good, you still can hear them, clear and loud. Their calls can go for 3 – 4 meters and sound quite weird and lovely. You can hear them call in the video below:

4. Mossy frog diet

Mossy frogs live in water basins, with only their eyes protruding to search for prey. Because they are nocturnal, they are very sneaky. The Vietnamese mossy frog diet mostly includes insects like worms, flies, cockroaches, crickets, and other invertebrates. Compared to the other adult frog species, they don’t eat much. The frogs only hunt two to three times per week.

Mossy frogs don’t eat and swallow food with a hard palate in their mouths since they don’t have it. Instead of that, they force the prey into their mouths with the help of their eyes. When these frogs wish to bring their food in, they pull their eyeballs to the roof of their mouth, pushing the food within.

5. Mossy frog breeding

The mating period of the Vietnamese mossy frog is between April and June. The male mossy frogs start to call around this time to show ladies how healthy and strong they are. The call sounds loving and sweet. They usually call in the early morning or immediately before sunrise.

After hearing the call and feeling the male is suitable, the female will lays eggs. The Vietnamese mossy frog, unlike other frog species, does not lay eggs in rivers or in the ponds. To keep aquatic predators away, the female will lay eggs on floating plants or above the watermark in rock caves. After that, the male will fertilize those gelatinous eggs.

In 15 – 20 days, tadpoles hatch. They will fall to the bottom of the waters and become metamorphosis. Their gills will be replaced by lungs, their hind legs emerge. The head gets more prominent, while the body spreads and lengthens, the front legs grow. They lose their tail by absorbing it back.  

Depending on the temperature, the metamorphosis to a froglet can take 4 to 8 months or longer. The period is shorter if the water is warmer. When the froglet has completed metamorphosis, it exits the nursery for an adult Vietnamese mossy frog habitat. 


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