AMPHIBIANS
Amphibians
are primeval vertebrates and compared to birds and mammals,
they have distinct differences as they lack hairs and feathers.
Their life cycle begins in water, where they respirate with
gills. Later on, they develop the ability to live on land, where
they respirate with lungs.
In
addition, they are poikilotherms (cold-blooded) and either their
body temperature is the same as their environment’s or they
absorb heat sitting on sunny places. During very cold weather
or when the sun is hidden, their activity decreases, but this
disadvantage is balanced by the fact that very little inner
heat needs to be produced and amphibians can live with minimum
food.
The
animal group of the amphibians depends on external heat for
its energy, so it cannot remain active when air temperature
is very low. Therefore, animals living in very cold areas have
to hibernate. In fact, some amphibians hibernate inside water.
The hibernation time differs for each amphibian according to
local climate: it can reach two thirds of the year in the North,
while in the South some species may not hibernate at all. Most
amphibians are diurnal, others are active only during the evening
and others only at night.
Τhe
biggest part of the amphibians lays eggs with a gelatinous sheath.
They usually are deposited in the water, where they grow into
animals differing markedly from their parents. These aquatic
larvae (tadpoles) feed for a period of time, until they transform
into miniatures of their parents.
Amphibians
exist on Earth for over 400 million years. Of the 46 amphibian
species of Europe, 22 are recorded from Greece, categorized
as ones with tail (such as salamanders and newts) and as ones
without tail, such as frogs and toads. In Parnitha it is assumed
that 7 of the 22 species of our country exist (Amorgianiotis
& Vavizos, 1997). These are:
|
Scientific
name
|
Common
name
|
|
?Salamandra
salamandra
|
Fire
salamander
|
|
Bufo
bufo
|
Common
toad
|
|
Bufo
viridis
|
European
green toad
|
|
Hyla
arborea
|
European
tree frog
|
|
Rana
graeca
|
Greek
frog
|
|
Rana
dalmatina
|
Agile
frog
|
|
Rana
ridibunda
|
Marsh
frog
|
? Its occurance in Parnitha is doubtful
