Here we have broken metamorphosis down so you can see the stages a tadpole goes through as it develops into an adult. It is important to note that the frogs in the following pictures are not all the same species.
This is an egg mass laid by a frog. Each of those black dots is made up of a bunch of cells that will eventually grow into a tadpole. Depending on the species, these egg masses can be made up of several hundred eggs! Within a few days, the eggs develop into tadpoles. Tadpoles live completely underwater. Over about a 24 hour period, the tadpole develops into a frog. This means almost every organ has to change so the tadpole can go from living underwater to living on land as an adult frog.
In this picture you can see the tadpole has started to grow hind legs. After the hind legs have started to form, a pair of front legs will begin to develop and the tail will start to disappear. You might also notice that the tadpole has started to form a frog-like face. Tadpoles are mostly vegetarian , grazing on algae that grow in leaf or rock surfaces under the water.
Sometimes, very large tadpoles, such as bullfrog tadpoles, become meat-eaters and sometimes even eat other frogs! Does anything eat frogs? Tadpoles can be a significant food item for fish, mammals, and even other adult frogs. Adult frogs are preyed upon by snakes, raccoons, herons, and other terrestrial land-based predators.
There are no hard and fast rules, but in general: Toads have dry, warty skin and relatively short legs for hopping. Frogs have smooth, damp skin and long legs for swimming or leaping. Can toads really give you warts? Toads do not give people warts. Amphibians have many glands in their skin, and several species produce highly toxic secretions for protection. Toads do secrete a substance from the skin that can be very irritating if it comes into contact with mucous membranes like the eyes, nose, mouth, etc.
How do frogs make their calls, or "ribbets"? In some species, such as Spring Peepers, the lower part of the mouth can become a large resonating vocal sac. When the frog closes its mouth and nostrils, and then forces air from the lungs over the vocal chords, the sac inflates and vibrates like a drum , producing long, loud trills. Other species just produce calls with the vocal chords.
Why do frogs call? Frogs and toads make a variety of sounds, depending on the situation. The most common are "advertisement" calls, and "alarm" calls. Toads have poison glands in their skin to keep predators from eating them and oftentimes produce a funny smell when handled. Sometimes there are frogs that are called toads but are technically frogs, this can be confusing… and there are frogs that have bumps on their skin and toads that have smooth skin.
And there is the Horny toad which is not a frog or toad, it is actually a reptile! Yes, even amphibians that hibernate in the mud underwater breathe during hibernation.
Since amphibians can breathe through their skin, they can absorb oxygen in the water during hibernation. They have to hibernate in water that has a good amount of oxygen in it and sometimes will actually swim around in the water during winter to maintain proper oxygen levels. There are a few frogs that can stop their heart and breathing completely and still survive. They are able to do this by keeping a high level of glucose in their blood that acts like antifreeze and protects their vital organs.
When the weather warms up, they wake up and their heart and breathing will resume normally. Nobody really knows! At this point in time, there has been very little research in frog sleep patterns. It is known that they close their eyes, but no confirming brain scans have determined whether or not they actually have a true sleep period. Frogs do not have external ears like us.
However, they do have eardrums and an inner ear. Some frogs have small tympanums, while others have ones that are larger than their eyes.
The size of the tympanum and the distance between them are relative to the frequency and wavelength of the species male call.
Their eardrum works like a regular eardrum with one very special adaptation…it is actually connected to their lungs. The lungs vibrate and are almost as sensitive to hearing as the eardrum. This allows frogs to make really loud sounds without hurting their own eardrums! The lungs are capable of doing this by equalizing the pressure differences between the outer surface of the eardrum and the inner surface of the eardrum.
Frogs use their eyeballs to swallow. Frogs eat their prey whole and their eyeballs actually sink down into their mouth and push the food down into their throat. It depends on the species. It can be really hard to tell the males from the females because the sex organs are internal for both males and females. But in many species, the female is larger than the male and the males sometimes have larger toe pads used during mating to grab onto the female.
Males also call to attract females and defend their territory, so if you see a frog calling it is probably a male.
The throats of many male frogs are darker than the females. In certain species, it can be easy to tell the difference. In Bullfrogs, the males are larger and have a larger tympanum these are ears-the circles located directly behind the eyes. In many tropical frogs, the males have brighter more vibrant colors.
Frog eggs do not have a shell, so they need some kind of moisture to keep them from drying out until they hatch.
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