Frogs | Nature Adventure

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Biology

Frog or toad? The distinction between the two is flimsy at best. Toads are a type of frog, being both amphibians with closely related family trees, but not every frog is considered a toad! The main differences come down to their body characteristics, or "morphology". Frogs have semi-permeable skin that they breathe through, and they need to be kept moist to stay healthy. They have long legs and prefer to leap great distances in order to get around. Toads have lumpier skin, can become dry without issue, and make shorter hops. Toads are also usually bulkier, with deeper croaks! But there are exceptions to every rule, and deciding what we call a toad versus a frog is fairly subjective!

Frogs and toads are found all over the world, but don't often survive well in colder environments! They're most commonly found in tropic and sub-tropic regions, where there's a lot of ambient humidity and water for them to swim in. As semi-amphibious animals, they do need a source of water to lay their eggs in! Their first stages of life are spent as tadpoles, which don't have any limbs at all. As they grow, they metamorphose into their adult frog bodies, which are then able to leave the water in search of prey!

Baby tadpoles release chemicals into the water letting their siblings know when to hatch. This increases the odds that any one individual will survive. As they grow, they disperse from their home ponds quickly, as almost frog species will cannibalize frogs that are smaller than them!

Ecological Importance

Frogs eat a huge variety of insects! They use their sticky tongues to grab bugs off the ground and out of the air. Some frogs might even eat small fish, and one species is even large enough to eat birds! They aren't generally known to be picky with their meals, and so help keep populations of insects down to a manageable level. As tadpoles, they feed on insect larvae and algae.

Over time, frogs themselves will be eaten by birds, fish, snakes, small mammals, and even other frogs!

But their most important aspect to ecologists is as an indicator species; these are animals that let us know when something's really wrong with their environments! Since frogs breathe and absorb water through their skin, they are highly vulnerable to toxins and pollutants in the water. Their eggs also need water to hatch in, and tadpoles must be able to survive in ponds long enough to metamorphose into full adults before their water source dries up. Monitoring frog populations can tell us a lot about the ecosystem and how it's changing!

Did you know?

The very first cloned animal using nuclear transfer was actually a frog!

When you hear about animal cloning, almost everyone talks about Dolly the sheep. But before Dolly, there were a few cloned animals that had to be made in order for the scientists to practice their technique.

Nuclear transfer refers to the process where a nucleus from one cell is removed and placed inside an empty embryonic egg. While this had been done with tadpoles in the early 1950s, the results weren't very encouraging; the frogs that resulted from this method were usually deformed and did not survive well into adulthood. This is because the scientists were using embryonic cells instead of fully-formed tadpole cells to populate the empty eggs.

In 1958, when the nucleus from the cells of a tadpole's intestinal lining were placed into the egg instead, it suddenly worked! A genetic clone of the original tadpole was made, and this paved the way for the researchers to move on to cloning mammals like Dolly.

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