Source: D4K: “Amphibians"
Visit the D4K companion Web site to learn more about Amphibians: D4K: “Amphibians"
This video segment from IdahoPTV's D4K explores the life and anatomy of a frog, an amphibian. It explains what it means to be cold-blooded, why frogs hibernate, and why they croak. You can follow their life cycle and see some amazing videos of frogs eating with their specially adapted tongue.
Joan Cartan-Hansen: Amphibians are cold blooded.
CHILD: Why did your frog go to the hospital?
CHILD: To get a hopperation.
CHILD: So what do cold blooded animals do when it’s really cold outside?
JOAN: Well, they hibernate just like a bear. Well, not exactly like a bear.
See this frog? It’s frozen solid. In the colder months it buries itself in the wet dirt and spends the winter well, kind of like a popsicle. It even stops breathing.
But each spring when the world begins to thaw it comes back to life. But like a popsicle, frogs and other cold blooded animals don’t like it when it gets too hot either.
CHILD: So what do they do?
JOAN: Some amphibians like this spade foot toad chill out by digging back into the dirt where it’s cool. This is called estivation. It’s like hibernation in the summer except now amphibians are trying to beat the heat instead of avoiding the cold.
CHILD: How deep can a frog dig?
CHILD MIMICKING FROG
JOAN: But before it gets too hot, amphibians have another job to do. They have to find a mate and reproduce.
Male frogs and toads attract their mates by singing.
JOAN: Oh, not exactly. More like this –
ribbit, ribbit, croak
JOAN: Each kind of frog or toad has its own song. These songs attract the female so the pair can mate.
A group of singing male frogs can be very loud so listen for them when you’re near a pond this spring.
Uh, it works better if you’re really a frog.
Frogs lay their eggs in the water. These eggs are in a substance that looks like, well, snott.
JOAN: Yeah, it sounds gross but this protects the egg from drying out and from soaking up too much extra water.
How fast the eggs develop depends upon the temperature of the water. The warmer the water the faster the eggs develop into larvae. Larvae are the next stage of growth.
Salamander larvae look kind of like their parents but the eggs of frogs and toads develop into tadpoles that look pretty different from mom and dad.
Amphibian larvae will stay in the water until they become adults. Going from egg to larvae to adult is called metamorphosis.
For amphibians this means starting life as a water animal and becoming an adult that spends most of its time on land – a double life.
CHILD: What did the frog order at Mcdonalds?
CHILD: French fries and a diet croak.
JOAN: Amphibian larvae are eating machines, munching mostly on water plants like algae. But as they become adults they begin to eat other things like the bugs that live in the water.
CHILD: What did the frog say to the fly?
CHILD: You are really starting to bug me.
JOAN: Most adult amphibians eat invertebrates, animals that don’t have a backbone like this cricket. Worms, slugs and other insects also make a good snack.
Large amphibians like the bull frog can eat pretty big creatures like mice and birds. In fact amphibians eat a lot of animals we think of as pests.
CHILD: How does a frog catch something like a fly?
CHILD : HEY!
CHILD: They are really fast.
JOAN: Amphibians are able to catch their food because they have big mouths and a pretty awesome tongue.
Their tongue is sticky and it attaches in the front of their mouth instead of the back like your tongue.
When food walks past or flies by open goes the mouth, out comes the tongue, dinner is served.
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