Rabb’s Fringe-Limbed Treefrog Facts, Pictures & Information For Kids & Adults

Rabb's fringe-limbed treefrog was a large flying frog found in Panama. The species was discovered in 2005. Sadly, Rabb's fringe-limbed treefrog is now believed to be extinct. The species was last reported in the wild in 2007.

Rabb's fringe-limbed treefrog was an amazing species in a number of ways: it was able to change its colour; it could glide; and perhaps most remarkable of all, its tadpoles gained nourishment by feeding on their father's skin – an adaptation not seen in any other frog species!

On this page you can find out about Rabb's fringe-limbed treefrog, and also discover what led to its (probable) extinction …

Rabb's fringe-limbed treefrog
Ecnomiohyla rabborum. Photo by Brian Gratwicke from DC, USA [CC BY 2.0], via Wikimedia Commons

Rabb's Fringe-Limbed Treefrog Facts At A Glance

  • Scientific name: Ecnomiohyla rabborum
  • Type of Animal: Amphibian
  • Animal Family: Hylidae
  • Where Found: Panama
  • Snout-Vent Length: 62 to 97 mm (2.4 to 3.8 in) male; 61 to 100 mm (2.4 to 3.9 in) female
  • Conservation Status: Critically Endangered (now believed to be extinct)

Meet The Rabb's Fringe-Limbed Treefrog: Introduction

Rabb's fringe-limbed treefrog was an arboreal (tree-dwelling) frog species found in Panama (the southernmost country of the continent of North America). It was first discovered in 2005 and formally described (i.e. named and recognized as a species) in 2008.

Rabb's fringe-limbed treefrog was last recorded in the wild in 2007. The species  is now believed to be extinct.

Rabb's fringe-limbed treefrog was named in honor of the herpetologists George and Mary Rabb, who were also known for their conservation work.

(Herpetologists are zoologists who specialize in amphibians and reptiles.)

The generic name Ecnomiohyla is derived from the Greek word meaning unusual ('ecnomios') and Hylas, a companion of Hercules in classical mythology.

What Did The Rabb's Fringe-Limbed Treefrog Look Like?

Rabb's fringe-limbed treefrog was a relatively large frog species. Its slightly flattened head was wider than its body, and it had a long snout with protruding nostrils. Its large eyes were reddish-brown in color, and wider in diameter that the tympana (eardrums).

The frog’s arms were short and stout, while its hind legs were slender and fairly long. The feet were fully webbed, and the short fingers and toes had large, flat discs at their tips.

During the breeding season, the humerus bone of the adult male Rabb's fringe-limbed treefrog developed pronounced extensions. Studded with spines made of keratin (a hard organic material), these bony structures appeared on the frog’s forearms. They are thought to have helped the male frog grip the female during mating.

The skin of the Rabb's fringe-limbed treefrog had a granular texture and was a mottled brown color. The rear surface of the thighs was pale yellow, and the belly was white with irregular specks of brown.

Color-Changing Frog

Rabb's fringe-limbed treefrog was capable of voluntary metachrosis (i.e. changing the color of the skin). By expanding special pigment cells in its skin, the frog could alter the position and appearance of the green flecks on its back, flanks and eyelids.


Rabb's fringe-limbed treefrog tadpoles had flattened bodies, short snouts and small mouths. The eyes of the tadpoles were positioned on the top of their heads and pointed out towards the sides.


Rabb's fringe-limbed treefrog was only ever recorded in a tiny area of forest in the Central American country of Panama.

The frog's entire known range consisted of an area less than 100 km2 (39 mi2) in size. The site is located near the town of El Valle de Antón in central Panama.

You can see the area in which Rabb's fringe-limbed treefrog lived on the map below (you can zoom in and out to see where it is in relation to the rest of the world):

The species was recorded on mountain slopes facing the Pacific Ocean at elevations between 900 and 1,150 m (2,950 to 3,770 ft.) .

Rabb's Fringe-Limbed Treefrog Habitat

Rabb's fringe-limbed treefrog inhabited the canopy layer of tropical premontane and montane forests (i.e. forests found on foothills and mountain slopes).

Most of the recorded observations of the species were from primary forest* habitats, although observations were also made in secondary forest habitats.

(*Primary forests are untouched forests that have never been harvested. Secondary forests are forests that have re-grown after having been harvested.)

Rabb's fringe-limbed treefrog Behavior

Like most frog species, the Rabb's fringe-limbed treefrog was nocturnal (active at night).

Flying Frog

Rabb's fringe-limbed treefrog had the ability to escape from predators by launching itself from tree branches and gliding through the air. It was known to glide from heights of up to 9 m (30 ft.).

The extensive webbing on the frog's hands and feet acts acted as a parachute. The frog may even have been able to steer itself in a specific direction.


Rabb's fringe-limbed treefrog bred in water-filled cavities in trees. The highly territorial males guarded these holes throughout the year, calling both to attract females and to deter rival males.

The frogs' calling increased in intensity a few days before and after a full moon, as well as during the peak mating season. This occurred around the beginning of the wet season (mid-March to May).

A single calling bout of the male frog was made up of a 'grrrck' sound repeated at regular intervals for up to 2 minutes. Sometimes the calling began with an owl-like call of 3 to 5 notes. Typically, the male called from a branch situated near the tree hollow that it was guarding.

During mating, the female laid 60 to 200 eggs inside the tree hole. The eggs were attached to the wood just above the waterline. The female then departed, leaving the male to guard the clutch.

Tadpoles That Ate Their Parent’s Skin!

After the eggs hatched, the male would spend the day partly submerged in the water while the tadpoles fed on its skin. The Rabb's fringe-limbed treefrog is the first and only frog species that has been observed providing nourishment for its young in this way.

What Does The Rabb's Fringe-Limbed Treefrog Eat?

The Rabb's fringe-limbed treefrog ate a variety of insects, including cockroaches and crickets.

Is The Rabb's Fringe-Limbed Treefrog Extinct?

The photo below shows the last living Rabb's fringe-limbed tree frog; a male named Toughie, who lived at the Atlanta Botanical Gardens.

Ecnomiohyla rabborum. Photo by Brian Gratwicke from DC, USA [CC BY 2.0]
The Rabb's fringe-limbed treefrog was rated 'Critically Endangered' by the IUCN when last assessed in 2009.

Already uncommon when first discovered, the last known record of the species in the wild is from 2007. The record consists of a single male having been heard calling.

Attempts to preserve the species using captive breeding were unsuccessful. The last living captive individual (a male known as Toughie) died in 2016 at the Atlanta Botanical Gardens.

It is highly likely that the species is now extinct.

The most likely causes that lead to Rabb's fringe-limbed treefrog's extinction include:

  • Habitat loss: The already small area occupied by the species was subject to deforestation, and deterioration / loss of suitable habitat due to human activities. These include the development of luxury holiday homes.
  • Fungal disease: Chytridiomycosis – a severe infectious fungal disease caused by the chytrid fungus (Batrachochytrium dendrobatidis) has been responsible for dramatic declines in amphibian populations in some parts of the world. The disease was detected in the area occupied by the Rabb's fringe-limbed treefrog in 2006, shortly before the disappearance of the species in the wild.

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