The common frog is widespread in Europe (except for the Iberian Peninsula). Also, it is not common in Crimea, Caucasus and Lower Volga. In the East, it may hardly be found behind the Urals. The common frog lives on floodplains, near springs, in the swamps, on banks of lakes, in the forest. It avoids salt water. It feeds on terrestrial insects, mollusks, spiders, earthworms, depending on the season and habitat. The common frog hibernates in winter. Near Moscow frogs re-emerge around the middle of April. Having woken up, they hurry to lay eggs. The development of the eggs is influenced by temperature. The higher the temperature, the faster they develop. Usually tadpoles hatch between the 8th and the 10th day. Further development takes from 50 up to 90 days. The optimal temperature for their development is between 21 and 26 degrees Celsius (69 – 79 degrees Fahrenheit). Tadpoles group into colonies. Approximately 1.5 months after they hatch they disperse in the water body and live solitary lives. They feed in the shallows, amidst vegetation. They keep growing three or more years after metamorphosis. Frogs achieve the stage of sexual maturity on the third year of their life. A common frog’s average life span is from 4 to 5 years. Common frogs are amphibians; their bodies can reach the maximum length of 10 cm. A frog’s head is wide and slightly flattened. On the sides of its head from the eye to the shoulder there is a temporal spot. Frogs vary in color, from light-yellow to dark-brown with marble patterns on the belly. During mating season male frogs’ necks become bluish.