Pattern of growth in a temperate zone anuran (Bufo viridis Laur.)

Growth in body length and mass was followed in 1‐year‐old toads Bufo viridis collected early August, kept in the laboratory at 20°C, and fed meal worms ad libitum for 24 h once or twice a week. The nutritional condition of the toads was evaluated from the condition index (CI) = 1,000 × body mass (g) × length (cm)−3. The rates of growth in length were high initially, in August and September, and then dropped to insignificant levels. Growth was abruptly resumed in spring, and growth rates were high in March to May. The CI increased to a maximum in September. During the period of growth stagnation it tended to decrease. After growth was resumed in spring, the CI again increased, but with a delay. During autumn the toads allocated food for lean growth and fattening, and eventually reduced feeding and growth, according to the pattern typical of toads in nature. This pattern was not affected by artificial long days. It is thus suggested that 1‐year‐old Bufo viridis exhibit inherent control of the behavioral and physiological mechanisms that prepare the organism for hibernation. During the spring period of growth the toads were out of phase with toads in nature. However, the synchrony of growth among the experimental toads continued. It is suggested that the second growth period also may represent an inherent functional pattern that was prematurely initiated under the conditions of the experiment.