Goliath Frog

Quick Take

• This frog pre-dates the dinosaurs, and the story of how it survived while they didn't is stranger than you'd expect. Explore its ancient origins →
• Despite having no vocal sac, the male Goliath Frog still manages to call for a mate, though not in any way you'd predict. See the vocalization comparison →
• The world's largest frog can move rocks heavier than most people would bother lifting, and its reason for doing so is surprisingly tender. Discover the nest-building strength →
• Goliath Frogs have only one known predator, and it is not the crocodiles or monitor lizards that share their habitat. Find out who hunts them →

The Goliath Frog is an endangered species of frog that lives exclusively in Equatorial Guinea and Cameroon in Africa. It can also be referred to as a goliath bullfrog or a giant slippery frog. This amphibian got its name due to its large size. These amazing creatures can grow to be about the size of a pet cat.

4 Incredible Goliath Frog Facts

• Goliath frogs are endangered.
• Goliath frogs can leap forward ten feet.
• Goliath frogs are nocturnal.
• Goliath frogs move heavy rocks to build nests.

Evolution And History

This frog has a long history, dating back more than 250 million years to the Paleozoic era, and is one of the few amphibians still in existence that lived before dinosaurs roamed the Earth. The oldest fossil found of a frog was from the early Triassic era, 251 to 247 million years ago, although this ancient ancestor, Triadobatrachus, may be from even further back than originally thought. Triadobatrachus is the oldest known member of the frog’s lineage.

Classification and Scientific Name

The common name of this frog is Goliath Frog, with alternate names Giant Slippery Frog and Goliath Bullfrog. The scientific name of the frog is Conraua goliath. It belongs to the phylum Chordata, class Amphibia, in the family Conrauidae.

The word conraua is thought to come from a German man named Gustav Conrau, who may have collected the first Conraua robusta, otherwise known as the Cameroon slippery frog. The word goliath is derived from the Latin Goliath, from the Hebrew word golyath, meaning “a giant.” Perhaps the most well-known use of Goliath refers to the Philistine giant David defeated in the Old Testament of the Bible.

Goliath Frog Vs. African Bullfrog

The Goliath frog is sometimes confused with the African bullfrog due to some similarities the two species share. For example, both of these frogs are native to Africa, are carnivorous, and are much larger than many other frog species. There are, however, more than a few distinguishing differences between these two frogs.

First, although the African bullfrog is considered one of the largest frogs, it is significantly smaller than the goliath frog. African bullfrogs can weigh up to around three pounds and measure between seven and ten inches in length, though females are considerably smaller than males. Another distinguishing trait is that African bullfrogs make a loud croak, whereas goliath frogs do not. Additionally, African bullfrogs hibernate in the dry season, whereas goliath frogs do not.

Appearance

These frogs have bumpy skin that contains glands that they use to drink water and obtain oxygen. The dorsal coloring is usually a brownish-green color with various spots. The ventral coloring can be either yellow-green or yellow-orange. Their coloring helps camouflage them in their environment. As a mature adult, these frogs can reach up to 32 centimeters long, which is six times the height of a golf tee. Their weight can vary between 1.3 lbs (about three times as heavy as a hamster) and 7.2 lbs (about half the weight of a bowling ball).

Behavior

These frogs are solitary animals. They can swim very fast but will often wait for prey to catch with their long tongue. They can leap large distances — up to ten feet — despite their tremendous size. They are also quite strong, able to move heavy rocks over four pounds to create nests.

Habitat

These frogs are native to Africa. The range of their habitat is limited, existing only in the regions of Cameroon and Equatorial Guinea. Their natural habitats are freshwater and tropical environments, within the rainforest and near rivers. They can also be found in zoos around the world, such as the San Diego Zoo and the San Francisco Zoo, both located in California.

Diet

Adult frogs are carnivorous. They eat a variety of organisms such as insects, fish, crustaceans, mollusks, amphibians including smaller frogs, and sometimes small mammals. Some of the species these frogs like to snack on include dragonflies, worms, spiders, newts, salamanders, crabs, and small snakes. These are just some examples of their diverse diet. It has even been documented that one of these giants had eaten a bat; therefore, these frogs could have additional prey that is not yet known to researchers.

Tadpoles are herbivores and feed on only one plant species called Podostemaceae, which is a type of river weed found in tropical habitats.

Predators And Threats

The only known predator of these frogs is humans. However, potential predators include large lizards such as monitor lizards, crocodiles, and snakes.

Tadpoles may become prey to a few predators, including birds, snakes, dragonfly larvae, and hedgehogs.

Humans are the biggest threat to these frogs. Hunting these frogs for their meat and exporting them in large numbers for the pet trade have been the two main contributing factors to the decline of this species for many years. Farming and development are also destroying their natural habitat. As their habitat continues to degrade, their population declines as well.

Reproduction And Life Cycle

These frogs mate through sexual reproduction and lay eggs, similarly to other frog species. Before mating, male frogs will build a nest for the offspring. Sometimes the male moves large rocks to create the nest. The male frog uses a call that is different from those of most other frogs. This is because the goliath frog lacks a vocal sac. Instead, he produces a whistling sound from his mouth.

Once the pair mates, the male frog departs. The female frog lays several hundred to several thousand eggs. After 85 to 95 days, the eggs hatch, and tadpoles are released into the water. The mother frog does not care for her tadpoles the way other animals care for their young. They are independent and must find their own food. The tadpoles reach maturity around ten to twelve months old.

These frogs usually live around 15 years in the wild. Although there have been goliath frogs that lived to 20 years in captivity, they do not thrive when not in their natural habitat.

Population

Unfortunately, exactly how many of these animals exist in the wild today is unknown. What is known is that the population has been steadily decreasing. According to the IUCN, the International Union for Conservation of Nature, the status of this frog is endangered and is included in their ”Red List of Threatened Species.”