Here’s a detailed comparison to help you distinguish between the eggs (spawn) and tadpoles of the Australian green tree frog (Ranoidea caerulea) and the invasive cane toad (Rhinella marina).
Eggs (Spawn)
Feature
Green Tree Frog (Native)
Cane Toad (Invasive)
Appearance
Laid in foamy clumps or jelly-like masses
Laid in long, transparent jelly strings
Structure
Eggs often in clusters, sometimes foamy
Eggs form double rows in a gelatinous string
Location
Floating on surface or attached to vegetation
Strands often wrapped around plants, submerged
Egg Color
Varies, but not in bead-like strings
Tiny black eggs, bead-like in appearance
Quantity
Hundreds to a few thousand per clutch
8,000–35,000 eggs per clutch
Protection
Foam or jelly helps prevent drying and predation
No individual casing, less protected
Key ID Tip: Green tree frog eggs are in clumps or foamy masses; cane toad eggs are always in long, bead-like gelatinous strings.
Tadpoles
Feature
Green Tree Frog Tadpoles
Cane Toad Tadpoles
Color
Brown, sometimes with visible veins in tail
Shiny jet black on top, blue-grey/black belly
Shape
More elongated, tail fin slightly veined, pointy tip
Oval-shaped, broad, with a pointed snout
Tail
Tail fin slightly marked with veins, pointy tip
Transparent fin, short tail
Behavior
Often solitary or loosely grouped
Swarm in large, slow-moving groups
Size
Generally larger than cane toad tadpoles
Small (up to 3 cm), usually smaller than frog tadpoles
Breathing
Come up to surface to breathe
Rarely surface to breathe
Toxicity
Non-toxic
Highly toxic at all life stages
Key ID Tip: Cane toad tadpoles are small, black, and form dense groups; green tree frog tadpoles are brown, larger, and more solitary.
Summary Table
Stage
Green Tree Frog (Native)
Cane Toad (Invasive)
Eggs
Clumps/foam/jelly masses
Long, bead-like gelatinous strings
Tadpoles
Brown, larger, pointy tail tip
Jet black, smaller, oval, group together
Other Notable Differences
Toxicity: Cane toad eggs, tadpoles, and adults are all toxic to most native predators, while green tree frogs are not.
Ecological Impact: Cane toads breed prolifically and their young outcompete and poison native species, including green tree frogs.
In summary: Green tree frog spawn appears as clumps or foamy masses, and their tadpoles are brown and somewhat solitary. Cane toad spawn is laid in long, bead-like strings, and their tadpoles are small, shiny black, and gather in dense groups-plus, they are highly toxic at all stages.
Green tree frogs face a variety of predators throughout their life stages, both in the wild and in areas influenced by human activity. Their main natural enemies differ slightly depending on whether they are tadpoles or adults.
Predators of Adult Green Tree Frogs
Snakes: Snakes are among the most significant predators of green tree frogs, capable of climbing trees and locating frogs by scent, which reduces the effectiveness of the frogs’ camouflage.
Birds: Many bird species prey on green tree frogs, using their keen eyesight to spot even well-camouflaged individuals.
Mammals:
Native mammals such as rodents may prey on frogs.
Since European settlement in Australia, introduced mammals like cats and dogs have become notable predators.
Other mammals, such as otters, raccoons, and squirrels, have been observed preying on tree frogs in some regions.
Other Frogs: Larger frogs, including other green tree frogs, may cannibalize smaller individuals.
Large Fish: In aquatic environments, large fish can prey on adult frogs, especially when they enter water bodies to breed.
Lizards: Some lizard species have also been recorded as predators.
Predators of Tadpoles and Juveniles
Fish: Tadpoles are highly vulnerable to predation by fish, which are efficient hunters of young amphibians.
Aquatic Insects: Predatory water bugs and other aquatic insects feed on tadpoles.
Birds: Birds will also eat tadpoles and juvenile frogs.
Other Frogs: Larger tadpoles and adult frogs, including conspecifics, may eat smaller tadpoles.
Other Threats
Cane Toads: In Australia, cane toads are both competitors and predators, and their presence has increased predation and competition pressures on native green tree frogs.
Humans (Indirectly): Habitat destruction, pollution, and the introduction of non-native species (such as cats, dogs, and cane toads) have increased predation risks and reduced safe habitats for green tree frogs.
Summary Table: Green Tree Frog Predators
Life Stage
Main Predators
Tadpoles
Fish, birds, aquatic insects, other frogs
Juveniles
Birds, fish, snakes, other frogs
Adults
Snakes, birds, mammals (cats, dogs, rodents), large fish, lizards, other frogs
Key Adaptations: Green tree frogs rely on camouflage, nocturnal habits, and their climbing ability to avoid many predators. However, their eggs and tadpoles remain especially vulnerable in aquatic environments, and adults are increasingly threatened by introduced mammalian predators and habitat changes.
