Description

The Fiji tree frog is, as the name describes, a tree dwelling frog. Despite its similar morphology to the the Fiji ground frog, there are some obvious differences between these two frogs. The Fiji tree frog is generally much smaller, with females ranging from 47-60 mm snout-vent length (SVL), males 32-45 mm SVL and metamorphs (hatchlings) from 9-11 mm. The skin colour of the Fiji tree frog is highly variable ranging from light creamy gray through to brilliant yellow, tans and oranges. Some individuals may have a contrasting cream coloured ‘X’ spot on the shoulder, a white spot on each shoulder or a white vertebral stripe running the length of the body.

Fiji tree frogs can be easily distinguished from Fiji ground frogs by their small size and the size of the finger discs. Fiji tree frog finger discs are much larger than their toe discs (see photo above). In Fiji ground frogs, the finger discs and toe discs are relatively the same size (see Fiji ground frog species account).

Frogs are NOT toads, and the Fiji frogs can be distinguished from the commonly seen, introduced and invasive cane toad (Chaunus [Bufo] marinus) by the frog’s relatively smooth and moist skin; the frog’s relatively longer hind legs and ability to leap more than 1m in distance. By comparison, cane toads can only hop a very short distance of only a few centimetres.

Distribution

Currently found in Viti Levu and Vanua Levu.

Habitat Ecology and Behaviour

Fiji’s endemic frogs are terrestrial breeders, and undergo direct development. That is, tiny froglets or miniature frogs, rather than tadpoles, emerge from hatched eggs. The Fiji tree frogs lay their eggs in leaf axils, particularly of Pandanus trees from November to April.

Like Fiji’s ground frogs our tree frogs are nocturnal animals and search for mates and forage for food (insects) at night. A recent study of the Fiji tree frog population in Savura, Viti Levu by Osborne (2007) shows that they have a close affinity to  Pandanus vitiensis and are often found on these plants close to a river system. Even though Fiji tree frogs may be observed in some disturbed sites, their habitat preferences are not as wide ranging as that of the Fiji ground frogs. They mostly found in closed canopy rainforest that is not often disturbed by human activity. Fiji tree frogs also appear to have a stronger association with river systems than do ground frogs. These frogs are good swimmers and climbers, and are evasive jumpers so they can be quite difficult to catch on a first attempt.

The Fiji frogs are one of the few species in the world where both females and males call. The call sounds much like a dripping tap, and is quite difficult to hear near a loud, fast flowing stream.

Threats

Even though the Fiji tree frog is not considered as endangered as the Fiji ground frog, further habitat destruction and deforestation could drive the existing small and isolated population to extinction.

The Pacific boa (Candoia bibroni) and introduced mammalian predators such as the small Indian mongoose (Herpestes javanicus), rats (Rattus spp.), and feral cats (Felis catus) are also potential threats. Unlike the cane toad, Fiji’s endemic frogs are highly vulnerable to desiccation (drying out). Fiji tree frog activities are thus restricted to primary forest, close to river systems that allow them to stay moist.

Conservation Status

Even though the Fiji tree frog is not considered as endangered as the Fiji ground frog, further habitat destruction and deforestation could drive the existing small and isolated population to extinction.

The Pacific boa (Candoia bibroni) and introduced mammalian predators such as the small Indian mongoose (Herpestes javanicus), rats (Rattus spp.), and feral cats (Felis catus) are also potential threats. However, because of the arboreal nature of the Fiji tree frogs, they may not be as threatened by these predators as the Fiji ground frog.

Unlike the cane toad, Fiji’s endemic frogs are highly vulnerable to desiccation (drying out). Fiji tree frog activities are thus restricted to primary forest, close to river systems that allow them to stay moist.

Remarks and Cultural Significance

Even though the Fiji tree frog is not considered as endangered as the Fiji ground frog, further habitat destruction and deforestation could drive the existing small and isolated population to extinction.

The Pacific boa (Candoia bibroni) and introduced mammalian predators such as the small Indian mongoose (Herpestes javanicus), rats (Rattus spp.), and feral cats (Felis catus) are also potential threats. However, because of the arboreal nature of the Fiji tree frogs, they may not be as threatened by these predators as the Fiji ground frog.

Unlike the cane toad, Fiji’s endemic frogs are highly vulnerable to desiccation (drying out). Fiji tree frog activities are thus restricted to primary forest, close to river systems that allow them to stay moist.

References

Brown 2004;
Gorham 1968, 1971;
Graeffe 1986;
Kuruyawa et al. 2004;
Morrison 2003, 2005; Narayan et al. 2004, 2007;
Osborne 2007; Ryan 1984, 2000;
Thomas 2007;
Watson 1960;
Worthy 2001;
Young et al. 2006;
Zug et al. 2004.

Front Page Photo: Tamara Osborne: an adult female Fiji Tree frog perched on the leaf of a shrub.