Imagine yourself on a trip exploring western Africa. You are walking toward the cascades of the Mbia River. The total drop is no more than twenty feet, but all you can hear is the explosive rumbling hiss of rushing water.
You trip and fall, feeling spray from the waterfall on your face. As you lie there, looking toward the water, your eyes focus on an unexpected shape in front of you. Its appearance is as striking as the river itself, its size is unbelievable.
Drenched by the mist, the object is as wet as you, and just as motionless. A sudden flicker from the creature's mouth provides the needed clue. This could only be Goliath (Conraua goliath), the giant frog, snatching flying insects from the hazy air above the waterfall.
This accident is what happened to a nice naturalist by the name of Jorge Sabater Pi back in 1960. A curator for the Barcelona Zoo in West Africa, he has investigated these frogs and written several key papers on this amazing amphibian, first identified in 1906.
In his quest to uncover the life of the secretive frog, Sabater was aided by the people of a local tribe called the Fangs. Their name for the Goliath is Niamoa, meaning "mother's son, because its size and limbs remind them of a small child. One of the Fang, named Ondo, had a reputation as one of the few men able to catch the frog alive.
Even with Ondo's help, Sabater's efforts took nearly all his energy. Silence and patience paid off when Ondo snagged one of the frogs with a fishhook dangling from a pole. Carefully removing the hook from the frog's barely injured skin, the explorer placed it safely in a protective container and began the long, treacherous journey back to camp.
On examination, the frog proved to be female, but this was not obvious. On the outside, the Goliath sexes are indistinguishable. Only during mating season, in July and August, can the male be identified by the slightly swollen first digit on each of its forelimbs. The swelling is caused by clasping its mate.
Sabater's female weighed in at seven pounds, four and a half ounces (7 lbs, 4.5 oz). It had a snout vent length of about thirteen inches and measured thirty-two inches overall with legs extended. This established a world record for the largest frog set in 1960.
The frog family contains over 250 true frog species, and the biggest is the Goliath, found only in the countries of Cameroon and Equatorial Guinea. These large frogs are notorious cannibals and readily devour smaller frogs. They will eat almost anything that is smaller than itself, including flying insects, mice and small reptiles.
Goliath has an incredible ten-foot leap, but it can only make three or four such bounds before giving in to exhaustion. In its own habitat, that allows plenty of time to make an escape. They are shy, sharp-eyed and quick to dive out of sight.
Sabater wanted to know if this amphibian was large from its beginning. he journey back to the cascades and waded into waist-deep water to collect Goliath embryos. They were barely larger than those of a common bullfrog. Goliath's early stages give no hint of its future gigantic proportions. Its eggs, tadpoles and young are not much larger than any other of the world's frogs. It is only metamorphosis that unleashes the mysterious growth force.
Another surprise about the frog's development, after the tadpoles ingest the yolk sack, they wiggle about and feed on plants for two to three months. The body then sprouts legs, absorbs its tail and transforms the juvenile vegetarian into an awesome, adult carnivore.
For all of its formidable attributes, wildlife biologists consider the Goliath frog vulnerable to extinction. It is currently unprotected by conservation laws. The Cameroon government allows 300 individuals to be exported each year, though the best professional collectors typically find but a few dozen. In spite of its elusiveness and remote rain forest habitat, human activity encoaches on the giant's domain.
[Photo Credit: Taken by Theodore Papenfuss, Apr 1, 1981, Nyabessan, 157 km. S.W. Ebolowa., Cameroun (Cameroon) on an expedition funded by National Geographic Society and Bronx Zoo.]
More Info:
Goliath Frog American Museum of Natural History
Conraua goliath Fact Sheet AmphibianWeb