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 use a variety of defence mechanisms to protect themselves from predators, combining physical, chemical, and behavioural strategies:
Camouflage: Their green coloration allows them to blend in with leaves and vegetation, making it difficult for predators to spot them. By remaining motionless during the day and hiding in foliage, tree hollows, or crevices, they further avoid detection.
Climbing Ability: Thanks to their sticky toe pads, green tree frogs can quickly escape ground-based threats by climbing trees or vegetation, moving to locations that many predators cannot easily reach.
Skin Secretions: When threatened, green tree frogs can secrete a noxious, sometimes sticky substance from their skin. This secretion can be irritating or distasteful to predators, deterring attacks and sometimes causing the predator to release the frog.
Behavioral Tactics: Like many frogs, they may jump away suddenly or leap into water or higher branches to escape. Some frogs puff up their bodies to appear larger and more intimidating, or even play dead to avoid attracting attention.
Colour Change: Green tree frogs can change their skin color to better match their environment, enhancing their camouflage and making them less visible to predators.
These combined adaptations help green tree frogs survive in environments with numerous predators, from snakes and birds to mammals and larger frogs. Their reliance on camouflage, rapid escape, and chemical defenses are especially important for avoiding predation in the wild.
