Advertising for a mate can also attract predators.



Bufo marinus , defends itself against a toad-eater snake.
 

Predator and prey, a balance in nature.


 

 

Unlike the more familiar kinds of bats that catch and eat their prey in flight, foliage gleaners pluck large stationery insects directly from their perches. The Frog-eating bat, a carnivorous foliage gleaner, sometimes supplements its diet of frogs with large insects, such as katydids.

Mating calls
It has long been suspected that foliage gleaning bats use the mating calls of their prey to locate them for food.

 Perhaps the most dramatic example is the Frog-eating bat (Trachops cirrhosus), a carnivorous foliage gleaner that uses the mating calls of small frogs to locate them.

The Round-eared bat (Tonatia silvicola) has also been shown to use mating calls of katydids as feeding cues. Round-eared bats and Frog-eating bats are very closely related and share habitat in the lowland forests of Panama.

Studies of these two species demonstrated the importance of mating calls in locating prey and also showed that different species of foliage gleaners can avoid competition for limited food resources by responding to the calls of different prey species.

Not surprisingly, as an anti-predator defense, frogs were discovered to produce calls that made it difficult for the bats to locate the source.

What technique is this frog using to avoid predators?

How about this for camouflage?

              Megophrys nasuta  Photo permission © Takeshi Ebinuma,  endless@interone.jp

The leaf frog takes camouflage to a new level! The pointed snout, projections over the eyes, and ridged "veins" running down its back give this frog the option of disappearing into leaf litter. Predators help drive the evolution of camouflage by eating every frog they can find. A leaf frog that looks even slightly more leaf-like than its neighbor has a better chance to survive and reproduce, passing its genes to the next generation. Ref American Museum of Natural History

A forest specialist, the Malayan Horned Frog has remarkable camouflage; its colour and form mimicking the leaf litter to be found on the forest floor. Unless the frog moves to snatch some unwary prey, it is unlikely to be seen.
More pictures

Some frogs use camouflage to avoid predators. The patterns and colors of a frog's skin, and sometimes the shape of its body, can help it blend into its surroundings.
 

Could this be the most poisonous frog in the world?

Photo David Hunter from Environment Australia
The Corroboree Frog, Australia's rarest frog.
Frogs reintroduced

Project corroboree 
The Southern Corroboree frog is on the brink of extinction. The last hope for this species now lies in a captive breeding program involving secondary school students at the Amphibian Research Centre in Victoria, Australia.

In the wild the Southern Corroboree Frog lives on Mt Kosciuszko. Only 150 adults remain in their natural habitat. In frost hollows atop, the male of the species builds a nest in the vegetation surrounding bogs. The female then lays about 30 eggs. Tadpoles hatch as the snow melts and then, almost a year after egg laying, the newly metamorphosed and extremely precious new frogs emerge.
 

When the team have identified a breeding site, they listen carefully and mark the exact spot where the male frog is calling from. This is the place where they will later find an egg mass. These sites are marked and protected by small enclosures. The frogs deposit eggs in mossy "nests" and the male frog will usually stay by the eggs as they develop. The recovery team remove some of the egg masses from the nests and they are transported to Melbourne so they can be expertly cared for in favourable conditions.		More stamps
Global Decline When species spiral towards extinction there are often several factors working against them. The mysterious global frog killer the chytrid fungus eats keratin, a vital component of the frog's skin and has been shown to lead to death in many frog species. Victoria's Spotted Tree Frog has had its populations reduced and fragmented by introduced trout. This has then left them vulnerable to local extinction from a range of  factors including the chytrid fungus. "In the end, we will conserve only what we love. We will love only what we understand. We will understand only what we are taught." Baba Dioum, Senegal

Teacher reference:

Can you find this frog?


 

Camouflage and poison colours.
How are they working together?
What is happening as it walks away?



The Southern Toadlet predicts the weather

Nothing is without meaning in nature. Bright colours usually warn of toxins protecting the bearer, while other less protected frogs try not to be seen. Some employ both strategies.

The Southern Toadlet and its eggs are well camouflaged from above but as it starts to walk orange legs give warning. A persistent predator may even get to see its underside but may not get to see tomorrow if the warning goes unheeded.

The skin of the Southern Toadlet, like its relative the Corroboree Frog, contains one of the most toxic compounds found in nature.

Frog chemist creates a deadlier poison 
Scientists have discovered a poisonous frog that takes up a toxin from its food and makes the chemical even deadlier.

Colour and camouflage
Many frogs that look dull and unassuming at first have what are called "flash colors"--hidden patches of bright color or patterns on their bellies, groins, or the backs of their thighs. For example, the plain brown back of the fire-bellied toad matches the ground on which it spends most of its time. When threatened, the toad exposes its bright red underside. Surprising displays of this kind can startle or confuse predators into fleeing, or at least buy the frog some time in which to make an escape.
 

What if the predator or bird turns the frog over?

Fire-bellied toads use skin color for protection. The skin on the toad's back is green and black, providing camouflage from above. When disturbed, the toad throws its legs into the air, revealing a bright orange "fire belly." If flashing these bright colors doesn't scare the predator, the toad has toxic skin secretions that make it an unpalatable meal.

REF: American Museum of Natural History
 

Brown tree frogs. How many eggs can you see?
Why does it need to lay so many eggs?



Listen to the audio: How many eggs will the Brown Tree Frog Lay?
 

What is going to happen to a lot of these eggs and tadpoles?



Listen to the audio: List the predators that Gerry mentions that will eat eggs and tadpoles.
 

During the breeding season, the loud call of a male milk frog lures a female to his water-filled tree hollow. The female lays her eggs in the pool and leaves the male to fertilize them and care for the young. After the tadpoles hatch, the male lures another female to lay eggs in the same water hole. He doesn't fertilize the second batch of eggs, but uses them to feed his hungry tadpoles. By "faking" a love interest, he tricks the second female into delivering food for babies that are not hers.

REF: American Museum of Natural History

 

A tadpole's mouth.



 

Partners can look the same.
Why is the male on top?

Partners can look different.

Staying on top of things when your arms are too short to hold on. How?


 

Nuptual pads.

The toe pads of most tree frogs are covered with tubular cells standing on end. These tiny bristles compress and bend under pressure, allowing the toe pad to "form-fit" over irregular surfaces. Mucus on the tips of the bristles allows them to stick to almost anything. Most tree frogs can climb straight up trees, cling to the undersides of leaves, or hang preposterously from a branch by one toe.
REF: American Museum of Natural History

When reptiles, birds, and mammals mate, the male fertilizes the eggs inside the female's body. Like fish, almost all frogs fertilize the eggs on the outside. The male holds the female around the waist in a mating hug called amplexus. He fertilizes the eggs as the female lays them. Amplexus can last hours or days—one pair of Andean toads stayed in amplexus for four months!

REF: American Museum of Natural History