Quick Take
- This frog skips one of the most iconic stages of amphibian life entirely, and her babies are born ready for the world as a result. See the direct development strategy →
- She's called a 'marsupial frog,' but she has nothing to do with marsupials. The real reason behind the name is stranger than it sounds. Discover the naming explanation →
- Most frogs have wildly different reproductive strategies than you'd expect, and this species takes the most extreme route of all. Compare frog reproductive strategies →
- You can actually see the embryos developing inside the eggs, and the footage is unlike anything most people have ever witnessed. Watch the embryos developing →
We are used to seeing some impressive parenting in the animal kingdom, but this mother frog takes the job very literally. The frog in this extraordinary clip is Hemiphractus scutatus, commonly called Spix’s horned treefrog. Females of this species carry their developing eggs openly on their backs rather than leaving them behind in a pond or nest. The species is found across the upper Amazon Basin in Colombia, Ecuador, Peru, Bolivia, and western Brazil.
If you look closely at the footage, you can even make out the developing embryos inside the eggs. Researchers have documented clutches of about five to 17 eggs in this species, with females carrying them on their backs for roughly 10 weeks. H. scutatus also skips the familiar free-swimming tadpole stage. The embryos undergo direct development inside the eggs and eventually hatch as fully formed little froglets.
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Why Is It Called a Marsupial Frog?
The “marsupial” name comes from the unusual way these frogs brood their young, not because they are related to marsupial mammals. Members of the frog family Hemiphractidae carry developing eggs on the female’s back in several different ways. In Hemiphractus, including H. scutatus, the eggs remain exposed and attached directly to the mother’s back rather than being enclosed in a pouch.
True marsupials are a group of mammals that give birth to extremely undeveloped young, which continue developing while nursing after birth. Many species protect their young in a pouch, although not every marsupial has one. Kangaroos and wallabies are among the best-known examples. The comparison makes the frog’s common name easy to understand, but the two groups are otherwise very different animals.
How Do Frogs Normally Reproduce?
Most frog species lay spawn that develops into tadpoles.
©Danita Delimont/Shutterstock.com
Most frogs follow a more familiar reproductive path. During amplexus, a male typically clasps a female while she releases her eggs, which he fertilizes externally. Many species lay their eggs in water, but others use leaves, vegetation, moist ground, tree cavities, or other protected places. The jelly-like masses of eggs commonly associated with frogs are only one version of a surprisingly diverse range of reproductive strategies. In species with an aquatic larval stage, the embryos eventually hatch as tadpoles.
Tadpoles also vary much more than they sometimes get credit for. Many eat algae, plant material, and decaying organic matter, while others are omnivorous or even carnivorous. As they undergo metamorphosis, legs develop, the tail is gradually absorbed, and the body changes into the familiar frog form. The amount of time this takes differs widely among species and can also be influenced by conditions such as temperature, food availability, and how long water remains available. Hemiphractus scutatus bypasses that free-swimming chapter entirely. Its young finish their development on their mother’s back and hatch ready for life as tiny frogs.
