Frogs are amphibious animals that begin their lives in water as tadpoles and graduate to both water and land as adults. While some zoologists emphasize that there is actually no taxonomic difference between frogs and toads, frogs are usually distinguished from their close toad relatives by their colorful, moist and always smooth skin through which they absorb oxygen. Frogs and toads have small rudimentary teeth designed only to hold onto prey until the meal is swallowed whole and both animals lack salivary glands entirely. Thus, a query regarding the different uses of nonexistent frog saliva is moot. The term "frog saliva" has been given to a number of other substances, however, and has been referred to in unusual applications in warfare and cooking.
In some cases and depending upon the specific creature, frog and toad toxins are sometimes misidentified as poisonous frog saliva. A minority of frogs and toads utilize extreme coloration and various poisons excreted from their skins to warn off potential predators. Unfortunate animals that unwittingly ingest poisonous frogs or toads can experience extreme illness and even death. The poison produced by the skin of the Columbian Dart Frog is well known to indigenous people. Arrowheads or the points of weapon darts are rubbed against dart frogs to increase the lethality of the weapon.
Frog saliva is also erroneously thought to be a means by which frogs stun and capture insects for food. This mistake arises from a mix-up of entirely different species with different hunting techniques. Frogs do hunt insects, but only by means of their long tongues. When very quickly extended, a frog's coiled tongue unrolls to catch the insect on its sticky surface. Certain lizards and other animals — with the exception of frogs — do hunt by knocking down prey with an accurate and powerful spit of saliva.
When called for recipes, frog saliva — or Sheap Kap — is often identified as an ingredient in certain exotic Chinese desserts and frequently "translated" as Frog Saliva Soup. This is actually a misidentification, although picky or squeamish eaters may not be mollified by the true origin of the recipe ingredient: frog fallopian tubes. Double boiled for up to four hours to avoid scorching, the frog fallopian tubes are then mixed with gingko nuts, sugar and other spices to present the final creamy dessert.
Finally, if Frog Saliva Soup is too exotic for many Western diners, Bird's Nest Soup can always be substituted. Authentic Bird's Nest Soup — made and consumed in Asia — actually includes the nests of cave swifts constructed with cave swift saliva and is very expensive. The Western version of Bird's Nest Soup available from your local Chinese restaurant is similar in name only.