snakes belong to reptiles

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Snakes belong to reptiles . . Snakes are divided into: aglyph (without poison) back fanged (with poison in rear teeth) and fanged (with poison in fangs in the front of the jaw). - PowerPoint PPT Presentation

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Page 1: Snakes belong to reptiles
Page 2: Snakes belong to reptiles

Snakes belong to reptiles.

Snakes are divided into:• aglyph (without poison) • back fanged (with poison in rear teeth) and• fanged (with poison in fangs in the front of the jaw). Aglyphs and back fanged are harmless to humans and

most of the big animals. Only the fanged snakes, like vipers and cobras, are considered to be dangerous, but only when disturbed. In Crete there are no fanged species.

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Are there venomous snakes in Greece and which are they?

There are 23 different species of snakes in Greece therefore Greece considered as the richest country in variety of species in Europe.

Only seven species of snakes carry poison.

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• Five snakes belonging to the family Viperidae (vipers) have relatively strong poison, while the other two of the family Colubridae are back fanged and have weak poison, harmless to humans.

• Vipers are never found all together in one place. They are spread in different places all around Greece. These are: Viper - Vipera ammodytes Ottoman viper - Montivipera xanthina Milos Viper - Macrovipera schweizeri Astritis - Vipera berus Nanochentra - Vipera ursinii

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• Venomous Colubridae are:

Montpellier snake - Malpolon insignitus Cat Snake - Telescopus fallax

• No other reptile is venomous and they are all absolutely harmless to humans

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Hearing, Vision, Smell of Snakes • Snakes do not have ears and we could therefore say that

they are deaf.• Most snakes (except some with very good vision and

some other totally blind) do not see very well. They perceive more shapes and movements, rather than the details of the objects.

• The smell of snakes is excellent, but they do not smell the way the mammals do. A special organ located in the upper part of the oral cavity "organ of Jacobson», play a significant role in their smell. They use their forked tongue to collect volatile organic molecules which they “place” at the “organ of Jacobson”. This organ processes information, as the sensors of our nose do.

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What do we believe for snakes?• Snakes nowadays, are considered as “very bad”

animals, slimy, dangerous and symbols of evil. Therefore most people hate them.

• In ancient times snakes were symbols of rebirth and healing and were used in treating diseases, from where comes the symbol of Asclepius kept in Medicine today.

• Snakes are animals like any other. Snakes are afraid of man and their first reaction is to get away of him. Only out of fear will they attack something that is not food for them.

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Which is the role of snakes in the ecosystem?

• Snakes play a significant role in the balance of the ecosystem. In the first years of their life, they mainly feed on insects consuming large quantities of them. Later, after gaining the appropriate size, feed primarily on rodents, thus becoming one of the main predators of these, playing a crucial role in controlling populations.

• In its timelife one snake can consume up to 1000 rodents. Since rodents can easily propagate in large numbers, we can imagine how much the rodent population will be increased in an area, if one single snake is killed.

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Nose-horned Viper Vipera ammodytes

You can see Vipera ammodytes alive

in the Live Museumof the Natural History Museum

of Crete

It is probably

the most common viper of Europe and the most common venomous snake of Greece.

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It may be found from sea level to 2500m. It is active during the day, and sometimes also during the night when the weather temperature is high.

It prefers sunny, dry and rocky slopes with little vegetation.

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It often climbs on bushes and dry-stone walls. It breeds at the end of May and females give birth to 4-20 offspring at the end of August. Hibernation starts in October and ends in February-March.

It is found in Greece mainland, Peloponnese, Evia, Sporades, Ionian islands, Kyklades, Thasos and Samothrace. It is absent from Crete and some small islands.

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The scales over the nose form a horn-like structure. Superstitions attribute medical powers to this horn. Its venom is dangerous for humans. When it is threatened, it hisses loud and curls up into defensive position. It preys upon small mammals, lizards, frogs and birds. Its bite can be fatal to human if not treated.

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It reaches 65 cm in length. Females are bigger than males. It is active mainly during the day. Occurs at alpine areas, usually higher than 1600m above sea level.

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Hibernation starts in September- November and ends in spring. Females breed every other year and give birth to 3-18 offspring which may mature at the age of 3 or 4. It feeds on small mammals, small birds, amphibian and lizards. Its bite is poisonous not as strong as Nose-horned Viper's but still, medical treatment is advised in case of bite .

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Leopard SnakeZamenis situla

It is found in Greece mainland, Peloponnese, Evia, Crete, Chios, Lesvos,Samos, Kos, Rhodes, in the Ionian islands, Skopelos, Skyros, Salamina, Spetses, and Kyklades.

It is a harmless, non-venomous snake.

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Mates late in the spring and females lay only 2-8 eggs every other year.It feeds mainly on rodents but also on lizards and small birds. It may bite if caught.

It can be found often in human habitats, such as gardens and around houses.

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Its overall length reaches the 120cm. It occurs up to 1600m altitude and it can be found in two forms: striped and spotted. It is a diurnal snake that avoids high temperatures. It crawls carefully among stones and vegetation, and often climbs on small bushes and rocks.

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Its overall length is usually less than 1m. Females are larger than males. It habits all kinds of wetland areas, but also operates outside of water, often quite far away from it. It variables in colours and patterning. It swims very skillfully and fast. It feeds on amphibians, fish, rodents, reptiles, invertebrates and sometimes even small birds.

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Mates in the spring. The mating process can involve several males, forming a

pile around the female, claiming mating. The females, depending on the size, can deposit from 2 to 100 eggs (usually about 30) which hatch up to 2 months later.

If caught and threatened, it secretes a very smelly fluid and often pretends to be dead turning upside down with its mouth open with a protruding tongue.

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Dwarf SnakeEirenis modestus

It is a non-venomous, a very calm and completely harmless snake.

It is found in Lesvos, Chios, Samos, Samiopoula, Fourni, Leros, Kalymnos, Symi, Kassos, Karpathos, Kastellorizo, probably on other Dodecanese islands too.

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Its total length is up to 60cm, rarely more. Active mainly at twilight but also at daytime at shady areas. It hides under stones or in crevices, sometimes in small groups. Small and quite slow snake that hunts actively its prey.

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It feeds mainly on arthropods, but also on small lizards. It breeds early in the spring and females give birth to 3-8 eggs. Hatchling snakes are not longer than 12cm. A very calm snake and completely harmless.

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It is found in Peloponnese, Evia, Ionian islands, Skiathos, Skyros, Kyklades and probably on other islands too. Its total length reaches usually 150cm. Young individuals have different coloration than adults. It occurs in varied habitats, at altitudes up to 1400m. Diurnal snake that avoids high temperatures.

It hunts on the ground but often climbs on trees and bushes. It swims capably. Feeds on small mammals like mice, rats and small rabbits, also on birds, lizards, amphibians and eggs. It breeds in spring and females give birth to 3-18 eggs. Not a very aggressive snake, but it could bite if caught. Usually a quite gentle snake.

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Balkan Whip Snake Hierophis gemonensis

It is a non-venomous snake with total length up to 100cm.

It is found in Greece mainland, Peloponnese, Evia, Ioanian islands, some islets of Sporades, Aegina, islets of Argolikos Bay, Kithira, Crete and satelite islets.

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It occurs in varied habitats at altitudes from the sea level up to 1400m. Diurnal, fast and very active snake.

It hunts usually on the ground but it also climbs on bushes and small trees.

Feeds on small rodents, reptiles, small birds and big invertebrates. It breeds in spring and females give birth to 3-10 eggs. It may bite if caught. Harmless snake.

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Its head is barely distinguishable by two dark dots which correspond to its eyes. Its atrophic eyes are covered with scales. The scale at the end of its tail forms a hard pointy tip, which it uses to cling and move. Females give birth of 4-8 eggs 11-25mm long.

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It is a blind snake evolved for living underground. It can rarely be seen on the surface. Hunts and lives mainly in narrow worm burrows or it digs its own in loose soil with its hard, pointed tail tip. It hunts worms and arthropods.

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Its total length is 80cm, sometimes more. It variables in colouring. It is mainly nocturnal at summer but diurnal at spring and autumn. It occurs often at sunny combs with rocks and bushes where it sets ambush for migrant birds.

It feeds on rodents, other snakes and lizards. Breeds in May and lays 4 to 13 eggs.

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Its closest relatives are found in North Africa and the Eastern Mediterranean.

It is highly prized by reptile collectors, especially in its red form.

It's the only oviparous viper in Greece and Europe. Milos Viper is threatened mainly by degradation of its habitat, by illegal animal collection and motorways. The total animal population of the species is estimated to be less than 10.000. It is strictly protected.

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Its overall length is up to 2m. It is found in sporadic populations in mainland Greece, Peloponnese, Corfu and Paxi.

In some areas it occurs up to 2000m altitude. It is a diurnal snake that often climbs on bushes and trees with skill.

It feeds mainly on rodents, but also on small birds and lizards. Mates late in the spring and females lay 2-18 eggs that hatch about 2 months later. It may bite if caught.

Asclepius Snake is associated with Asclepius, the ancient god of medicine. The symbol of Asclepius rod wrapped by a snake is being used even nowadays as the symbol of medicine.

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Cat SnakeTelescopus fallax

It is a back-fanged species and is thus harmless to humans, in contrast to dangerous front-fanged species, such as vipers or cobras.

You can see Telescopus fallax alive in the Living Museum

of the Natural History Museum of Crete

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The venom of the Cat Snake is used more in the digestion process than for killing its prey.

Females give birth to 5-9 eggs which hatch usually in middle August. Usually hisses if handled and pretends attacking but it will almost never bite.

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It is found in Greece mainland, Peloponnese, Evia, Crete, Lesvos, Chios, Rodos, Symi, Samos, Ikaria, Karpathos, Kithitra, Antikithira, Kyklades, Kassos, Kalymnos, Koufonissi, Ionian islands, Strofades, Egina, Agkistri, Spetses and probably on other islands too.

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Some more Snakes you can see in NHMC

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Horned viper Cerastes cerastes

It is a highly

venomous sand-welling viper.

It is native to the deserts of Northern Africa and parts of the Middle East.

You can see Cerastes cerastes alive in the Living Museum

of the Natural History Museum of Crete

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The Horned Viper ambushes its prey covering itself with sand for camouflage.

It is primarily a nocturnal animal, feeding on small mammals and lizards. It is characterized by two horns over its head.

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Egyptian Cobra Naja haje

The Egyptian Cobra, Naja haje, is probably the most characteristic snake species, because of the expansion of its neck when threatened. It is It is absent from Greece (It is found in Africa and the Arabian Peninsula).

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It is extremely poisonous and may reach 2.5 meters in length. In ancient Egypt it decorated the Pharaoh’s crown symbolizing power over life and death.