Welcome to the most visited page on the SAVE THE FROGS! website…other than our homepage! We hope you enjoy these Cool Frog Facts and share them with your students, teachers, friends, and colleagues.
How many amphibian species are there?
As of September 1st, 2020, there are 8,224 known amphibian species, of which 7,255 are anurans (frogs and toads), 755 are caudates (newts and salamanders), and 214 are gymnophiones (caecilians). The total number tends to increase over time as scientists find and describe previously unknown species.
Do all amphibian species have tadpoles?
No. Some caecilians give birth to live young and some salamanders have larvae that essentially resemble the adult stage, but with external gills. There are many terrestrial frog species that emerge as froglets directly from the egg, bypassing the tadpole stage altogether. This adaptation allows them to live far from water bodies (on mountain tops for instance), and provides the parents with an increased ability to guard their eggs, which are laid on land. It also removes a serious risk that aquatic larvae must face: predation by fish or dragonfly larvae. Many terrestrial salamanders employ this strategy as well. (Photo credit: Frogden).
Photo of Midwife Toad (Alytes obstetricans) courtesy Anartz Garcia, Spain
How long have amphibians been around?
Amphibians are the oldest land vertebrates. Ichthyostega was an amphibian species that lived in Greenland about 363 million years ago.
The smallest frog in the world is Paedophryne amauensis, from Papua New Guinea, sizing in at only 7.7 mm long on average. P. amauensis produce such a high-pitched noise that they sound can like insects, and they are one of the frog species that skip the tadpole stage, hatching right into miniature adults. They are also the smallest vertebrate on the planet!
Other Papua New Guinea species, Paedophryne dekot, Paedophryne verrucosa, and Paedophryne switorum also average 8-9 mm in length, and could easily fit on a thumbnail!
Mini mum is a recently discovered species that hails from Madagascar that grows to be 8-10 mm long.
Next up is the critically endangered Monte Iberia Dwarf Frog (Eleutherodactylus iberia). These frogs measure only 10 mm (0.4 in) when fully grown. They are threatened by pesticides, deforestation and large-scale mining operations that destroy their habitat.
Izecksohn’s Toad (Brachycephalus didactylus) from southeastern Brazil reaches full size at only 10mm (0.4 in). It is known in Brazil as “sapo-pulga” — the Flea Toad.
The world’s largest frog is the Goliath Frog (Conraua goliath), which lives in western Africa. They can grow to be over 30 cm (1 ft) long, and weigh over 3 kg (6.6 lbs). This species is endangered, due to the conversion of rainforests into farmland, which disrupts their habitat, and also as a result of poaching: these huge frogs are often used as food by local people.