|
|
|
Frogs, Toads and Newts
- UK Amphibians
|
|
|
|
There
are around 6,200 living species of amphibians.
Amphibians is a name for all living tetrapods (four
legged vertebrates) that do not have amniotic eggs,
their body heat is regulated by their environment and
they generally spend most of their time on land. Once
known as cold-blooded this group of animals is now
called ectothermic. The study of amphibians and reptiles
is known as herpetology.
Amphibians
tend to head for freshwater for the reproduction cycle.
A few may head to brackish water but there are no
species that will tolerate sea water. Several hundred
frog species need no water at all. An evolutionary
adaptation has enabled them to be independent from
water. Almost all of these frogs live in rainforests and
their eggs are hatched directly into smaller versions of
the adult. The tadpole stage happens whilst in the egg.
Some species have adapted to semi arid conditions but
many still need water to lay their eggs. Amphibian
metamorphosis involves lots of changes from the infant
to the adult. Four legs appear in order to go on land,
gills are replaced by lungs, glands develop on the skin
to avoid dehydration, the tail disappears in frogs and
toads, the eyes adapt to have vision out of the water
and they grow eyelids and an eardrum is developed to
lock the middle ear.
The
first major group of amphibians evolved from fishes to
having legs. They were approx 5 metres long in length
and found that the land was safer for them from the sea
predators such as sharks. They did however encounter
problems in that their skin was not water tight and the
food they were used to eating was mainly water based.
Amphibians evolved and adapted to their new land based
lives and they moved up the food chain where they took
the position we now see modern crocodiles. These
amphibians ate mega-insects and fish. Amphibians
hibernated through the winter which enabled them to be
safe from the reptiles.
There
are three types of amphibians found in the UK, these are
frogs, toads and newts. You can tell the difference
between frogs and toads in a few ways. A frog will feel
moist when touched but a toad will feel dry. The skin of
a frog is smooth whereas a toad is warty. Toads backs
appear flatter than a fogs ridged back. A toad will walk
whereas a frog will hop.
|
|
|
|
|
 |
Common
Frog |
|
The common frog (Rana temporaria). Often seen from March
to October their lifespan is approx 6 years. The male is
approx 70mm long while the female is slightly larger.
Although called the common frog their existence is
diminishing due to the use of chemicals and their
natural habitats being destroyed. |
| Once found in
abundance in rural areas these frogs are now seeking
refuge in urban gardens. Here though they are faced with
a whole new set of problems such as cats and feasting on
slugs that have been poisoned with pellets. |
|
|
 |
Marsh
Frog |
| The marsh frog (Rana
ridibunda) can be seen all year round but is rare and
limited to the Kent and East Sussex areas. It can be
identified by its colourings of green and brown with
black markings and a strip of green/yellow going down
its back. Often found in streams, ponds and lakes. |
|
|
 |
Pool
Frog |
| The pool frog (Rana
lessonae) became extinct in the UK in the 1990's as a
result of their ponds being drained or becoming
overgrown. 70 frogs from Sweden were reintroduced to a
location in Norfolk recently. The colouring of the frog
is olive green with brown markings and a yellow strip
down the back. |
|
|
 |
Great
Crested Newt |
| The
great crested newt (Triturus cristatus) can be found in
many parts of England, Wales and southern Scotland and
can grow to 17cms in length. It is illegal to handle
these newts as they are a protected species. If they are
found to be in any danger then it is important to
contact the correct authorities who are able to move
them to safety. They can be seen from February to
October, they will then hibernate on dry land through
the winter. The colouring of these newts is what gives
them their name. A large crest can be seen on the male's
back during spring and they have an orange belly.
Predators resist from eating them as they release an
irritant from their skin and are quite foul
tasting. |
|
|
 |
Palmate
Newt |
| Palmate newts (Triturus
helveticus) are found in England, Scotland and Wales
usually in or near streams and ponds. They hibernate on
dry land from October to march. They can grow to 9cms in
length. Identified by the male's webbed back feet and
slight extension to the tail. |
|
|
 |
Smooth
Newt |
| Smooth newts (Triturus
vulgaris) are widely spread throughout the UK. They can
grow to 9cms in length and are sometimes confused with
the palmate newts. Smooth newts have spotted throats and
have orange bellies in the summer however there are
albino versions that are very pale coloured. Smooth
newts walk very slowly and are quite small. They head
for their breeding ponds once out of hibernation and
this causes a few problems for them. They may need to
cross roads or tackle kerbs and pavements to get there,
many get run over or fall down drains before reaching
their destination. It is okay for these newts to be
removed from danger by a member of the public as long as
they are placed in a suitable spot. |
|
|
 |
Common
Toad |
| The
common toad (Bufo bufo) can be seen all year round in
England, Scotland and Wales. The females are generally
longer than the males by approx 25mm. This toad will
camouflage its skin colouring to the soil as to blend
in. It is our largest amphibian. Easily spotted in the
spring when they begin to walk back to the pond in which
they were born. They tend to hunt their prey at night
and rest motionless in a hiding place through the day.
The skin of these toads will burn the mouth of any
predator that tries to eat them. |
|
|
 |
Natterjack
Toad |
| The natterjack toad (Bufo
calamita) is quite rare in the UK with only certain
areas having them. They can grown to approx 70 mms in
length. This toad has a yellow line down its back and is
often seen moving quite fast. Decline of this species is
due to many factors. Their natural habitat is being
destroyed or contaminated. The natterjack is also
extremely fussy in choosing where it will spawn. They
require a certain pH balance in a shallow pool with no
predators or vegetation, areas that are becoming
increasingly difficult to find. Because of this it is
illegal to disturb natterjack toads in any way. If you
find some in your garden or local rural area it is best
to inform the correct authorities who can ensure that no
work will commence whilst they are there. |
|
|
|
|
|
|
|
|
|
|
Amphibian
Conservation
It
is not just the amphibians in this country that
are feeling the wrath of human intervention. Many
of the amphibians worldwide are now in
decline. Amphibian populations have been
dramatically decreasing in substantial numbers for
the last two decades. Factors such as destruction
to their habitats, pollution, climate change and
predator introduction all play a part in this. The
hole in the ozone layer, which seems to have no
direct effect on humans, could be damaging
amphibians' skin, eyes and eggs because of the UV
rays. Discussions relating to the declines though
are still ongoing.
Evolutionarily Distinct and
Globally Endangered (EDGE) are commencing an
awareness and fundraising initiative in the hope
of gaining conservation for these creatures. ''The
EDGE amphibians are amongst the most remarkable
and unusual species on the planet and yet an
alarming 85% of the top 100 are receiving little
or no conservation attention and will become
extinct if action is not taken now.” Helen
Meredith, EDGE Amphibians coordinator, commented.
“These animals may not be cute and cuddly, but
hopefully their weird looks and bizarre behaviours
will inspire people to support their conservation”.
|
| |
| Forum
Questions... |
|
|
| Q:
''I have a small pond
and I am worried that my tadpoles will run out of
food, can I feed them?'' Mary
- Taunton |
| A:
Once
hatched your tadpoles will eat its yolk sac
and then in most cases turn on the yolk
sacs of unhatched tadpoles. Once the yolk
sacs have gone they will turn to algae,
microscopic organisms and plants, tadpoles
are vegetarian until they produce their back
legs. You can supplement their food by
dropping green veg like lettuce leaves and
cabbage into the pond - it can take a day
for the lettuce to soften sufficiently so
add a leaf a day, they can then eat the leaf
from the previous day. It has been advised
to boil the lettuce first but this will
actually rid the lettuce of its
nutrients. |
 |
| Once
your tadpoles start growing legs you need to
add meat to their diet, I use 'tubifex' and
meaty fish pellets from the local pet shop,
I have heard mince, dog & cat food biscuits
are good as well. Be careful not to add too
much food as this will rot and end up
fouling the water. Also do not top the water
up in your pond with tap water as the
chlorine is toxic to the tadpoles, use
rainwater from a water
butt or tap water that has
been left for a couple of days for the
chlorine to evaporate.- Bill |
|
|
|
Q:
''My frog spawn has
turned white, is it dead?'' Alan
- York |
| A:
It is very likely
Alan. When frog spawn turns a milky white colour
it usually means it has been hit by a hard frost.
This is common as the Spring temperature
fluctuates on an annual basis. You may find some
tadpoles will hatch from a couple of inches
further down and they will find themselves with an
abundance of yolk sacs as food and will get a very
good start in life. In some cases all the spawn
will have been affected. |
| All is not lost, in a
year that tadpoles fail, newts gain the advantage.
Tadpoles will eat newt eggs and newt larvae thus -
no tadpoles, more newts. I noticed this back in
2008, a late frost hit the spawn in my pond and
that summer I noticed a dramatic increase in the
newt larvae population. This proves to me that
actually nature is in balance and we should not
interfere too much. - Bill |
|
|
|
|
|
|
|
|
