The tadpole or pollywog is the first part of a tadpole’s life cycle. Frogs inhabit most of the world except for the polar regions, some oceanic islands, and deserts. Frogs are the largest group of amphibians with over 5,000 known species. They are relatively simple animals and have three stages of life: egg, larva, and adult. The first stage or larva is the tadpole stage
Tadpoles are considered entirely aquatic event though there are some species that are land loving. During their short and young life, breathing is done using autonomous external or internal gills. The do not have arms or legs until they reach adulthood, and can be see with large and flattened tails that aid them in swimming. Safety is of vital importance during the tadpole stage. They are often eaten by other aquatic animals, birds, and fish.
As a tadpole matures, it metamorphoses into a frog by progressively growing limbs and losing its tail. Lungs develop about the same time as legs develop. During this part of the tadpole’s life cycle, a tadpole can be found near the water’s surface and breathing air. In the final stages of external metamorphosis, the tadpole’s mouth changes from a small enclosed section at the front of the head to a large mouth that is the same width as the head.
Many types of tadpoles are herbivorous and eat algae and plants. There are some species of tadpoles, however, that are omnivorous and eat detritus and smaller tadpoles. You will find that tadpoles vary in size. Late stage tadpoles range from about 1.3 inches up to 4.2 inches. You may also find a tadpole who has grown up to almost 10 inches in length. These are the largest tadpoles and turn into large frogs and toads.
The first stage of a tadpole’s life cycle is the egg stage. The breeding season for frogs occurs during the spring time in temperate climates. Most frog and toad species lay their eggs is calm water near large amounts of vegetation. Here the eggs can develop in relative safety. Numerous eggs tend to clump together, and the mother just leaves them alone.
As fertilized eggs mature, the yolk in each egg splits into more cells and takes on the form of a tadpole. It takes about one to three weeks for the eggs to hatch and a tiny tadpole to emerge.
Most tadpoles attach themselves to weeds in the water and feed on the yolk of their birth egg. At this stage of a tadpole’s life cycle, tadpoles are very vulnerable, and they move very little.
Unfortunately, as a newborn tadpole, they are often eaten by other aquatic creatures. They do try to protect themselves by hiding or camouflaging themselves into their surroundings and burrowing into the mud.
Tadpoles are also very vulnerable to dry conditions. They need to water to survive, and a pond that dries up will also dry up its tadpole population.
About seven to fourteen days (depending on the species), tadpoles begin to swim around in the water. They become highly social and go through schooling periods just like fish. If you look near the banks of small ponds and streams, you may see tiny tadpoles swimming around in a crowd. These are the “schools” of tadpoles that tend to stay together for quite a while. The next thing to consider is what do tadpoles eat?
Tadpoles have long coiled intestines that thrive on water plants like algae, green herbs, plants, and weeds. At this point, they are considered herbivores or plant-eating specimens. They need high amounts of protein two times in their live, and one is in the seven to fourteen-day period.
The tadpole’s gills disappear about four weeks into their life. Tiny teeth begin to grow in their mouths, and they start to eat “harder foods” or tiny insects and larger plants. Internal organs start to become longer. Longer intestines and internal organs help tadpoles digest more nutrients. These nutrients are essential to maintain growth and metamorphosis during the tadpole cycle.
At about five to nine weeks in the tadpole’s life cycle, they begin to sprout legs. Their heads and abdomens grow proportionately. Diets become different types of small aquatic plants as well as insects that land in the water. At the end of the ninth week, tadpoles are almost recognizable as tiny frogs, but they still have long tails. They continue to change and the tail grows smaller.
The tadpole is nearing the mature stage, and now the tadpole no longer resembles a fish but are frog-like.
By the time the tadpole is twelve weeks old, they have become much larger. A tiny tail or “froglet” seems to be the only difference between the tadpole and a small frog. At this stage, the tadpole is ready to venture out of the water and live on dry land. During this period of evolution, the lungs start to function completely, the tail vanishes, the mouth widens to the width of their head, and their skin becomes “breathable.”
Within thirteen to sixteen weeks, a tadpole completes the tadpole’s life cycle and becomes a full-fledged frog or toad (frogs and toads are really the same amphibious creature). The amount of time it takes for a tadpole to turn into a frog is about twelve to fourteen weeks and is dependent on the environment or quality of the water and the supply of food and nutrition. ((Note: in cold areas, the tadpole will take all winter to develop into a frog.)
Once the tadpole has turned into a frog, the cycle starts all over again. The frog returns to the water to lay eggs and the eggs hatch into tadpoles, and the tadpole turn into frogs.