Green Toad (Bufo Viridis)

The green toad reaches a size of about 9 cm. The skin is lumpy, more keratinized than that of other toad species, and dry to the touch. The ridges are clearly visible on the sides of the head. These are glands (paratids) that secrete a poisonous white secret when the toad is defensive or angry.

Above, the body of a green toad is painted in light gray-olive tones with large dark green spots, edged with a narrow black border, often with red dots in the middle. The pupil of the eyes is black, horizontal, the iris is golden. The coloration is very variable.

The end of the fourth (outer) toe of the front foot extends beyond the first (end) joint of the third toe. The articular tubercles on the underside of the toes of the hind paws are usually single; longitudinal skin fold on the inner edge of the tarsus.

During the mating season, the male has black calluses on the first two or three toes of the forelegs.

The green toad is widespread in Southern and Central Europe, North Africa, Anterior, Middle and Central Asia, eastward to Western China and Western Mongolia. In the former USSR, its range covers the European part (to the north up to 60 ° N), Crimea, the Caucasus, Central Asia, Kazakhstan, Southern Siberia, extending east to Altai and north to 50 ° N. sh.

Green toad (Bufo viridis). © photo by Yu Ma

According to the peculiarities of the color of the upper side of the body and size, 8-10 subspecies are distinguished.

Within the USSR, most of the area is inhabited by the nominative form. It is possible that the B. v form lives in Southeast Turkmenistan. oblongus Nik., 1896, inhabiting Northern Iran and Northwestern Afghanistan. In the south-east of Tajikistan, V. v. Is probably widespread. pseudoradde Mert., 1971, living in Eastern Afghanistan and Nepal.

The systematic position of green toads inhabiting Uzbekistan and most of Turkmenistan is not clear. Perhaps a special subspecies lives here. In general, intraspecific variability has been insufficiently studied.

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The habitat of the green toad extends from the northern border of mixed and deciduous forests, across the steppe zone and deserts; in the mountains, these animals are found at an altitude of more than 3000 m above sea level. This is the most resistant species of amphibians in our fauna to dry habitats. With a loss of water equal to 50% of body weight, the toad does not die, while other tailless amphibians, in particular frogs, die with a loss of 15-20% of water.

Outside the breeding season, it leads a terrestrial lifestyle, being an ordinary inhabitant of fields, gardens, orchards.

The average number is 2-8 individuals per 100 m ², under optimal conditions in the south of the range, up to 100 or more adults were observed in the same area (with underyearlings up to 300 or more individuals).

The green toad is active at night and at dusk, spending the whole night until dawn in search of food (in the highlands it is active during the day). Compared to the gray toad, the green toad is more mobile, agile, can make short jumps, crawl quickly and can climb well, overcoming obstacles in the form of piles of stones, deposits of sand, earth, etc.

It feeds on terrestrial invertebrates, mainly insects, among which flightless forms account for about 50%. Beetles, caterpillars, bugs, ants, earwigs are of the greatest importance in nutrition.

In cold weather in summer, when the night air temperature drops to plus 8-10 ° C, toads do not go hunting and sit in their shelters for several days and even weeks until it gets warm. In warm cloudy weather, they often appear on the surface of the earth in the daytime.

In the Central Asian deserts, when all vegetation burns out and insects and other small animals that feed green toads disappear, the latter go into summer hibernation. This hibernation continues until late autumn and can go into winter hibernation without interruption. As a result, green toads living in deserts are active for only 4-4.5 months during the year.

The green toad usually hibernates in October - late November, depending on temperature conditions. As a rule, the activity drops sharply at a temperature of + 7 … + 8 ° С and stops at + 3-40 ° С. It hibernates in holes of rodents, holes, in heaps of stones, buries itself in loose ground.

In spring it appears from March to mid-May, depending on temperature conditions.

Toads moving to spawning grounds almost do not feed in their stomachs, only isolated insects and spiders are found.

Adult toads are hunted by snakes, herons, rooks, crows, badgers, otters, minks, etc.

For reproduction, it uses a wide variety of reservoirs, from small puddles with brackish water to quiet shallow waters of rivers and lakes (no deeper than 0.5 m). Spawning in the population is extended, so that green toads can be found in water bodies until July. Probably, this elongation is a useful biological adaptation contributing to the conservation of numbers, or rather, the survival of populations.

Males of the green toad are the first to enter the water bodies and emit melodious trills ("lyu-lyu-lyu" or "nrr … irr …"), while the unpaired resonator under the skin of the throat swells like a ball. The length of the testes of males in the second half of summer averages about 13.8% of the body length, in the fall before wintering it increases to 14.7%, and in the spring, during the breeding season, reaches 7.3-1.3 mm, which is about 15 % of body length.

The clutch is in the form of a cord up to 7 m long, in which the eggs are arranged in two rows. The cord can contain up to 12 800 eggs, but often their number does not exceed 3000-5000. Cords with caviar entwine underwater vegetation or lie on the bottom.

After mating and laying eggs, the males remain in the reservoir for some time.

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At a water temperature of + 21-23 ° C, the tadpoles of the green toad hatch in 3-6 days. The first 2-3 days they are inactive, and then begin to actively move and feed on phytoplankton, detritus, protozoa and small crustaceans. In the morning, tadpoles move from the deep parts of the reservoir to the coast, and in the evening - back. Development of tadpoles at a temperature of + 21 … + 24 ° С lasts 45-78 days. The branchial opening is located on the left side of the body, the anus is on the midline. The fin fold of the tail is of the same height throughout. The total length of the tadpoles is 9.5-10 mm. The number of tadpoles is quite large. The sex ratio is not equal: males make up 46-66%. With the onset of the appearance of the front and hind limbs, the tadpoles switch to feeding on terrestrial invertebrates.

Toads migrate to land in late summer or early autumn: they are small in size, their length is no more than 25-30 mm. For some time they keep along the banks of the reservoir, feed here, but reluctantly go into the water. Frightened, they jump into the water and immediately get out on the shore again, trying to hide on land. They grow slowly and reach sexual maturity only in the fourth year of life.

Sources:

1. Keys to amphibians and reptiles of the USSR fauna. Moscow, "Education", 1977

2. I. P. Sosnovsky. Amphibians and reptiles of the forest, Timber industry, 1983

3. Ya. I. Garanin, Amphibians and reptiles of the Volga-Kama region, Publishing house "Science", 1983