Life History
Some tadpoles are beautifully colored such as this eastern gray treefrog.
All Missouri toads and frogs must return to a body of water to reproduce. Most species breed during the late winter, spring or early summer, but southern leopard frogs, Rana sphenocephala, are also known to breed during rainy periods in the autumn. The majority of these amphibians select fishless bodies of water for breeding. Flooded fields, ditches, woodland and prairie ponds, and temporary pools are favorite breeding places. A few adventurous males locate an appropriate breeding pond when the temperature and humidity are suitable, and begin to call. Each species of toad or frog has a distinct breeding call which entices females to join them and select a mate.Soon, other males congregate and add their voices to the chorus. Females, heavy with eggs, enter the pond and are grasped by a male in an embrace called “amplexus” and begin the process of egg-laying. During egg-laying, the male’s vent opening is positioned just above the female’s vent, and as her eggs are released, the male fertilizes them with his milt. He will retain his firm grip on her until all the eggs have been laid.
Most eggs hatch within 10 to 14 days of being laid, but they may hatch much sooner if the water temperature is above 70 degrees F. The tiny, newly hatched tadpoles rest for a few days by clinging to aquatic plants, receiving nourishment from the last of the yolk sac stored in their bellies. Most Missouri tadpoles eat aquatic plants— especially algae—as they develop in the wetland. Tadpoles have gills, somewhat like fish, which are covered and protected by a flap of skin. As development progresses, the hind legs form and enlarge. The tail begins to shrink at this stage. As the front legs appear, the tail continues to become smaller. Soon the gills are not used, and the late-stage tadpole begins to breathe air at the surface, using brand-new lungs. The final stage of development from a tadpole to a young frog, known as a froglet, is the combination of the disappearance of the tail and the change from a life underwater to a life on land or along the edge of a pond or swamp. Soon after transforming from tadpoles to froglets or toadlets, these young amphibians begin eating insects, small spiders and worms. They grow quickly.
