Amphibians

Vous trouverez ici des informations sur les amphibiens que l’on peut observer dans le Léman.

species in the world
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species in Switzerland
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Migration sites listed in Switzerland by the Coordination Centre for the Protection of Amphibians and Reptiles in Switzerland (Karch)
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Amphibians of Lake Geneva

You can find out more about the amphibians of Lake Geneva in our section News in 60 seconds (number 89 and 98).

Introduction

Amphibians (formerly known as batrachians) are a class of vertebrates. This class is divided into three main groups: urodeles (newts and salamanders), anurans (frogs and toads), and gymnophiones or apodes (legless amphibians found only in the tropics). All the amphibians in the region are protected at national level.

All amphibians in the Lake Geneva region have four legs when fully developed. Urodeles (newts and salamanders) keep their tails after metamorphosis, which is not the case for anurans (frogs and toads). Their skin is permeable to water, which prevents them from drinking. What's more, the thinness of their skin allows for gas exchange and therefore partial respiration. This phenomenon is also made possible by the mucous membranes of the mouth, which is why batrachians can sometimes be seen making rapid throat movements. When the animal is out of the water, hydration of the skin is ensured by a series of glands on the body. These glands also produce secretions that protect it from disease or predators.

Amphibians are cold-blooded animals. Their bodies cannot produce heat, which means that their body temperature depends on the external temperature. They can, however, control their temperature by moving to a warm or cold place. They are essentially nocturnal species. This is when they are most active, hunting and breeding.

The life cycle of most amphibians is divided into two stages: from the egg hatches an aquatic larva (called a tadpole in anurans and a larva in urodeles), which breathes through gills. This is followed by metamorphosis, when the front and back legs develop and breathing becomes pulmonary, so that adults have to go to the surface to breathe.

In anurans, the diet changes from herbivorous to insectivorous. During this transition period, the tadpole's tail is absorbed and used as an energy reserve. While larvae are almost always aquatic, the adults' relationship with water varies from species to species. Some, such as the Common Toad or the Red-legged Frog, are only present at waterholes during the breeding season, while others, such as the various green frogs, stay all year round. Depending on the species, amphibians overwinter or hibernate in places protected from frost, such as crevices in the ground or under the mud of bodies of water.

Every spring, most amphibians (frogs, toads, newts) leave their winter habitat and arrive at the waterholes where they breed. During these migrations, amphibians face many obstacles and dangers (roads, low walls, wire fences down to the ground and other barriers). To limit the dangers associated with roads, "crapauducs" (a type of underpass for small animals) or buckets placed along particularly problematic stretches of road can be installed to intercept migrants. The buckets are then emptied on the other side of the road. In Switzerland, more than 100,000 amphibians are saved every year thanks to the efforts of associations and volunteers. For further information, visit www.karch-ge.ch.

Palmate newt (Lissotriton helveticus)

Discovered in 1789, the Triton palmé is the smallest of the newts found in Europe. 

Rather discreet thanks to its colouring, it is active at night, but can sometimes be seen during the day on rainy days. It can be recognised by its olive-green colouring, its flesh-coloured throat and its tail, which is marked with two rows of black dots surrounding an orange band. It is found all around Lake Geneva and feeds mainly on small invertebrates and crustaceans. It may also feed on frog tadpoles.

Observation period: larvae can be observed from mid-May to August. The adults leave the water in June-July to overwinter on land between November and February.  

Alpine Newt (Ichthyosaura alpestris)

A rare beauty, the male has a dorsal crest punctuated with black and white and flanks mottled blue to white. This species is most active at night. It is found throughout the Lake Geneva region and in all types of water. As the end of winter approaches, the adults return to the waterways to reproduce. They reach sexual maturity after 1 to 4 years and live a semi-aquatic lifestyle. Feeding on crustaceans, insects, invertebrates, tadpoles and other amphibians, it is mainly found in wetlands.

Période d’observation : de février à octobre, proche ou dans des points d’eau, d’octobre à février, en forêt.

 

Laughing frog (Pelophylax ridibundus)

Often confused with the Green Frog, the Laughing Frog spends most of its time in the water. It usually has dark brown spots, black mottled sides and light grey hind legs. Its spine is outlined with a prominent green line. It can also be recognised by its white belly and long hind legs. This frog has a variable internal temperature, depending on its climate. During the winter, it hibernates in the water. It chooses the calm sections of rivers, backwaters of lakes and ponds where it buries itself in deep, winding cavities. As an adult, the Laughing Frog is an insectivore, but will also eat other types of food such as fish, newts, lizards and small birds.

Period of observation: from March to October, its period of activity is concentrated in sunny hours.

 

Red frog (Rana temporaria)

The Red Frog can be found in any environment, whether in calm or busy water. It is the species with the most diverse coat, ranging from yellow to black... The Red Frog, one of the largest amphibians, can grow to 10 centimetres and weigh 100 grams. It is a terrestrial species that tends to live at night, although it can be seen during the day when it rains. Between February and November, it moves between its spawning and wintering grounds. During the winter, it takes shelter in relatively oxygenated water or damp ground.

Observation period: February to October.

 

Common toad (bufo bufo)

The Common Toad, Europe's largest toad, is the most widespread species in the region. With its stocky body and short hind legs, it is easily identifiable. Its skin, made up of numerous glands, is capable of secreting a liquid that enables it to defend itself against its enemies, including humans. After wintering in forests, Common Toads return to their breeding grounds (ponds, streams, lakes). Breeding takes place at the beginning of April, when the female lays her eggs in a lake or waterhole. The Common Toad feeds on any animal it can find within range, as long as the size of the animal does not exceed its capacity to swallow it.

Sightings: between February and September. During the winter, the Common Toad stays in a hole, in scree or in branches to protect itself from the cold, as it is a species that is very sensitive to frost. 

Flycatcher (Alytes obstetricans)

The Accoucheur Toad, also known as the Alyte, is an amphibian with warty skin and short legs. It is often found in wooded or sandy areas. It can be recognised by its grey-brown skin, white underside and golden eyes. The Accoucheur Toad is the only amphibian that mates on land and does not lay its eggs directly in the water. Instead, the eggs are first deposited in a "nest" formed by the legs of the two individuals. The male then fertilises the eggs before wrapping them around his shins. Once the eggs have matured (20 to 45 days), the male deposits them in a body of water where they hatch almost instantaneously.

Viewing period: March-April to September-October. As this species tends to be active at night, it is difficult to observe them during the day.

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