Current estimates state that almost 3% of all frog species, or roughly 200 species, have gone extinct since the 1970s (Alroy, 2015). This represents a critical loss of biodiversity. Additionally, over 33% of remaining frog species are thought to be faced with imminent extinction.
Thankfully though, many organizations are working to save the frogs that remain. I have been lucky enough to work with an organization trying to do just that, and I am incredibly passionate about sharing the plight of frogs with anybody and everybody.
The frog species that are unfortunately believed to be extinct include some truly incredible and unique animals. However, there are others that, while still imperiled, are posed to make a comeback.
While it would not be possible to list every extinct frog species, a few distinct examples are as follows.
The Gastric-Brooding Frog Rheobatrachus vitellinus
The Gastric-Brooding Frog was an incredibly unique species, native to Australia. It is believed to have gone extinct in the mid-1980s, and thought to be a victim of the deadly Chytrid fungus, a fungus that destroys amphibians’ delicate, critically-important skin (Ben-Ari, 2005).
The Gastric-Brooding Frog was unique for its reproduction, in which the frog would actually swallow its own eggs. The eggs’ slime coating was believed to have contained an enzyme that shut down the parent’s stomach acid, preventing the eggs from being digested.
The tadpoles would hatch, and even complete metamorphosis, within the adult frog’s stomach, before being vomited back up as miniature versions of the adult frog.
The Golden Toad Bufo periglenes
The Golden Toad, a brightly colored true toad native to Costa Rica, was only formally recognized by science for 25 years before becoming extinct.
The decline of the Golden Toad is not understood, given that it happened very rapidly, and in a pristine wildlife preserve. In 1987, over 1,500 toads were observed during their breeding season. In 1988, only one was observed, and 10 in 1989. However, since 1989, not a single Golden Toad has been observed.
While little is known about the extremely rapid decline of the Golden Toad, climate change, droughts, and diseases such as Chytrid have been considered as possible causes (Ochoa-Ochoa et al. 2015).
The Panamanian Golden Frog Atelopus zeteki
The Panamanian Golden Frog is a small, bright yellow frog with black spots, native to Panama. It is the only frog on this list to not be extinct- however, it is considered extinct in the wild.
In the early 2000s, the Chytrid fungus began decimating Panama’s frog populations. Conservationists raced to remove the last individuals of threatened species from their contaminated habitats, in hopes of breeding them in captivity to ensure the species’ survival.
Since a group of individuals were captured, the Panamanian Golden Frog has not been seen again the wild, leading to it being considered extinct in the wild. Thankfully, many successful captive breeding populations have since been established in Panama and the United States. Maybe someday these wonderful frogs can be safely reintroduced to their former habitat.
The Devil Toad Beelzebufo ampinga
The best known extinct prehistoric frog is Beelzebufo ampinga, which translates to devil toad!
Beelzebufo lived in Madagascar during the Cretaceous period, and likely looked similar to a much larger version of our modern-day Pacman Frog.
It is thought to have eaten small dinosaurs.
How Many Frogs are Extinct?
While it is unfortunately impossible to know exactly how many frog species have existed, and how many of those are now extinct, we do know that roughly 200 species, or 3% of all known frog species, are now extinct.
Many of these have become extinct in recent decades, including at least 90 species lost to the Chytrid fungus epidemic.
It is also possible that species currently thought to be extinct will reappear, having simply failed to be observed and therefore declared extinct.
This has happened many times- especially with animals that live in dense forests, it can be extremely difficult to observe small, secretive animals.
This makes it impossible to ever know exactly how many individuals exist of a given species.
Why Do Frogs Go Extinct?
There are many reasons for modern-day frog extinctions. The most accepted reasons frogs are endangered include climate change, habitat loss, disease, and invasive species.
Climate change affects frogs by altering the habitats in which they live. Many frog species have extremely specific environmental requirements, so even minor changes in temperature or humidity can be devastating.
Habitat loss is caused by human development. When wild habitat is destroyed for human use, the animals living there are either killed or displaced. What little natural habitat remains is not sufficient to maintain the level of wildlife that once lived on Earth.
Frogs have been very heavily impacted by disease. Chytridiomycosis, or chytrid, is a fungal disease that attacks the delicate skin amphibians use for drinking and breathing. Chytrid has spread throughout the world over the past few decades, and is already responsible for at least 90 amphibian extinctions.
Invasive species threaten native amphibians by creating unnatural competition for food and habitat, by spreading disease, and sometimes even by eating native amphibians.
Examples include the Cane Toad, which is native to South and Central America, but has become invasive in Florida in Australia. The Cane Toad out-competes native amphibians for habitat and food, and is deadly to native predators and pets that eat it.
This article was written in collaboration with another Master Herpetologist certified by the Amphibian Foundation.
Alroy, J. (2015). Current extinction rates of reptiles and amphibians. Proceedings of the National Academy of Sciences, 112(42), 13003–13008. https://doi.org/10.1073/pnas.1508681112
Ben-Ari, E. (2005). A new piece in the puzzle of global amphibian declines. BioScience, 55(1), 96. https://doi.org/10.1641/0006-3568(2005)055[0096:anpitp]2.0.co;2
Ochoa-Ochoa, L. M., Whittaker, R. J., & Ladle, R. J. (2013). The demise of the Golden Toad and the creation of a climate change icon species. Conservation and Society, 11(3), 291. https://doi.org/10.4103/0972-4923.121034
Cover Image: Michael J. Tyler, Science.
Beelzebufo Image: Drawing Credit: Nobu Tamura/Wikimedia Commons/CC 3.0
Image modified by the blog owner. Original version and licence available here.