In result of analyzing the rhythm of growth and development of common newt larvae (Triturus vulgaris), as shown in Fig.1, we have established the following: 1. The growth rate of the species in the time between 1-35 day of ontogenesis (in the stages of development 1-4) it is one exponential, dimensional growth being 0.8 mm daily, this fact demonstrates the existence in the breeding stations of investigated water basins, as well as, favorable conditions in terms of food and the microclimate. No less important in this regard is the lack of competition trophic and spatial intra- handed between the larval populations of common newt with those of notched newt (Triturus cristatus), which is because they are first operating in vital sectors less deep aquatic habitat and submerged denser vegetation. 2. In the second period of ontogeny (from 35th until 70th day) is observed practically a halt in the growth rate (larvae size remaining in fact, almost the same), given as the common newt larvae enters the final stages of development pre-metamorphic and metamorphic which are accompanied by certain changes in anatomy and physiology requiring more energy and plastic resources. As a result, the larvae complete their ontogenetic process, turning into juvenile whose body dimensions are 30 mm. Comparing the development and growth rhythm of common newt with the notched newt (see curves A and B in Fig. 1), we note that the larvae of notched newt have a similar rhythm to that of species studied by us only at the first ontogenetic stage (the day 1-35). Later, however, the growth of notched newt continually increases at the same exponentially mode (while the rhythm of common newt is stopped from its entry into the ontogeny final phase) reaches the maximum value at the 70th day of development: larvae it is characterized by the most advanced body size - about 65 mm. After this they also are entering and in to final stage of metamorphoses diminishing their sizes up to 43.5 mm (size of fresh metamorphosed individuals), but they are much bigger than those of common newt juveniles (equal to 30.0 mm). No less important is the fact that the notched newt do not feel a spatial concurrency and essential nutrient from other amphibian species that spawn in the same aqvatic basin. This is because notched newt reproduces itself with Triturus vulgaris , Hyla arborea and Rana dalmatina, was adapted to the new conditions of individual reproduction through the following features : ― nuptial games of the notched newt take place predominantly during the day time. Species of Triturus vulgaris having a relatively low density and being smaller, can not resist the oppression over the space exercised by Triturus cristatus; ― Larvae of Triturus cristatus, the predators and in a more advanced stage of development, with larger legally not compete with food for the larvae of Triturus vulgaris because they consume other prey. ― Also, because the larvae of these two sympatric species have different ecological niches, this allows them to minimize competition from living space required for the successful implementation of ontogenetic development. Thus, we see that the two syntopic species of local newts ( Triturus vulgaris and Triturus cristatus), besides the presence of certain similarities, there are obvious differences in the ontogenetic rythm, allowing them to coexist successfully in one and the same natural habitat.