Darwin’s Frogs: Gold-Star Fathers in the Animal Kingdom
In the vast and wide Animal Kingdom, newborn young of egg-laying species are often left by their parents to fend for themselves after hatching. Sometimes, the newborn animals may even face danger from their own parents, who may attack and eat them! Even when the newborn animals receive care from their parents, it is normally from the mother, who may have incubated them and takes care of them.
Yet, the situation is reversed in the case of frog native to the forest streams of Argentina and Chile, Rhinoderma darwinii, better known as Darwin’s Frog. Instead of simply fertilizing the eggs laid by the female and leaving, the male Darwin’s Frog goes above and beyond the call of duty, guarding the eggs for 2 weeks before they hatch, and then taking care of the young tadpoles until they mature and are able to fend for themselves. What is unique about the male Darwin’s Frog is the way in which it takes care of its young: by carrying them within its own throat! This creates the misleading illusion that the male Darwin’s Frog is actually “giving birth” from its mouth when the young emerge from the safety of its vocal sac.
But more than simply protecting its young within its own body, evidence has been found that points to the existence of a trophic relationship between the young and the parent: the larvae actually absorb nutrients from the parent frog. In a study conducted in 1986, by inserting several tracer chemicals into the parent frog, such a relationship was deemed possible, as the chemicals inserted were discovered in the bodies of the larvae (O. Goicoechea et al, 1986).
Such parental behavior on the part of the male animal certainly is quite unique within the Animal Kingdom, especially as the Darwin’s Frog not only protects its young but even carries them within itself and lets them absorb its nutrients. It’s no wonder that male Darwin’s Frogs were actually mistaken for viviparous females giving birth when first discovered. Truly a father that is worthy of a gold star!
“Darwin’s Frog: video, facts and news” BBC Wildife Finder. URL: “http://www.bbc.co.uk/nature/species/Darwin%27s_Frog”. (accessed 06 April 2010)
“Darwin’s Frog” by ChildCarriers.com. URL: “http://www.childcarriers.com/assets/popups/animals/img/THUMBS/darwinsfrogTB.jpg”. (accessed 07 April 2010.)
Oscar Goicoechea, Orlando Garrido and Boris Jorquera, 1986. Evidence for a Trophic Paternal-Larval Relationship in the Frog Rhinoderma darwinii Journal of Herpetology, Vol. 20, No. 2 (Jun., 1986), pp. 168-178