Holdridge's toad facts for kids
Quick facts for kids Holdridge's toad |
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Bufo holdridgei Taylor, 1952 |
The Holdridge's toad (Incilius holdridgei) is a special kind of toad. It lives only in Costa Rica. For a while, people thought it was extinct. This was because no one had seen it since 1987. The International Union for Conservation of Nature even listed it as extinct in 2008.
But then, in 2010, a scientist from Costa Rica found it again! This was exciting news. Now, the toad is listed as critically endangered. This means it is still in great danger. Scientists believe a fungus called chytrid fungus is the biggest threat to these toads.
Contents
About the Holdridge's Toad
Where it Lives
Holdridge's toads were first found on Barva Volcano in Costa Rica. They still live only in that small area. This area is part of Costa Rica's beautiful rainforests. The toad is named after the scientist Holdridge, who discovered it.
What it Looks Like
Adult male Holdridge's toads are about 32 to 46 millimeters long. That's about the length of a small paperclip. Females are a bit bigger, around 38 to 53 millimeters long.
Both males and females are dark in color. They can be black or light brown on their backs. Their bellies are usually lighter. They have reddish bumps, called warts, on their bodies and legs. These warts come in different sizes.
Their heads are wide. They have smooth, round glands behind their eyes. These glands are reddish. Their legs are short. Their hands and feet are a bit fleshy. They also have some webbing between their toes.
One very interesting thing about these toads is that they cannot hear. They also cannot make sounds. This means they don't have mating calls like many other frogs and toads.
Baby Holdridge's toads, called tadpoles, are small. They have dark brown, oval-shaped bodies. Their tails are rounded.
How it Behaves
Holdridge's toads like to burrow underground. This means they are "fossorial." They stay mostly hidden. When it rains a lot, you might find them under leaves and other stuff on the forest floor. During dry times, they like to be near stream banks.
They become more active during the day. They also move around more at dusk, which is evening time. As mentioned, these toads are deaf and mute. They don't use sound to talk to each other. This is very rare for toads.
Before 1986, it was easy to find these toads during their mating season. This was from April to May. Hundreds of them would gather. But outside of this time, they were hard to find. Since 1987, their numbers have dropped a lot. They are now critically endangered. Since they were found again in 2010, only a few have been seen. This makes them one of the most threatened toads in the world.
What it Eats
Scientists are still learning a lot about the Holdridge's toad. From past studies, we know what they like to eat. Holdridge's toads eat many different small bugs. These include spiders, caterpillars, flies, beetles, earwigs, ants, and mites.
Life Cycle and Reproduction
Holdridge's toads likely become adults around two years old. Since they can't make sounds, they don't have mating calls.
They are called "explosive breeders." This means they lay many eggs at once. They lay their large eggs in pools of water on the forest floor. They have also been known to lay eggs in man-made ditches. In the past, they would breed in open areas like pastures. But now, these areas are turning back into forests.
Male toads usually arrive at these breeding pools first. This happens after heavy rains, around early to mid-April. They wait for the females to arrive. Sometimes, there were so many toads that males would try to mate with other species. Females usually stay at the breeding pool for only about an hour.
History and Conservation
Why it Almost Vanished
The Holdridge's toad was not seen for over 20 years, from 1986 to 2009. Because of this, the International Union for Conservation of Nature said it was extinct. Scientists searched for seven years before declaring it extinct.
Many things might have caused the toad to disappear. One big reason is a disease called chytridiomycosis. This disease is caused by a fungus. It affects amphibians like toads. The fungus grows on their skin. High levels of this fungus were found where the toads used to breed.
Other reasons for their decline might include climate change and forests being cut down.
Rediscovery and Current Status
In 2009, scientists found tadpoles and adult toads again. They were found in two different ponds. This discovery changed the toad's status. It was no longer extinct but critically endangered.
From 2008 to 2010, many searches were done. These searches showed that there are likely fewer than 50 adult toads left. Finding young toads means they are still reproducing. But there are no large groups of them anymore.
The area where Holdridge's toads live is protected. It is part of Parque Nacional Braulio Carrillo. However, some breeding ponds are near a main road. More tourists could threaten these areas.
Protecting the Toads
The Holdridge's toad was added to the Red List of Endangered Species in 2006. Scientists have seen the toad on 22 out of 40 visits. They have counted 67 toads in total.
Most of the toad's known home is protected in a national park. The two places where the toad was found in 2010 are in smaller refuges. These refuges do not have the same level of protection as a national park. But their forests are still safe.
Even though the toad was found again, we still don't know much about its population. More research is needed. We need to learn about how many toads there are. We also need to study their breeding sites, health, and genetics.
A special project is helping to monitor these toads. It is supported by the Mohamed Bin Zayed Species Conservation Fund.
Scientists believe the main reason for the toad's population drop is the chytrid fungus. This fungus is linked to global warming.
