The word Amphibian is derived from the Greek word amphibios, which means ‘a being of double life’. It is a very apt name for amphibians and refers to their ability to live both in water and on land in the various stages of their life cycle. Even amphibians, who spend the majority of their lives on land, will return to the water to breed. Amphibians are thought to be the first vertebrates to leave the water and start life on land over 350 million years ago. They played an important part in the evolution of all vertebrates and have adapted to life in many habitats throughout the world.
There are certain characteristics that define an amphibian. Generally they have skin which is permeable to water, so they appreciate life in or near water sources and in damp places. They are cold-blooded and rely on their surroundings to control their body temperature. They usually spawn jelly-like eggs that hatch into aquatic young in the form of gill-breathing larvae or tadpoles. The young will undergo metamorphosis to take on their adult form, which usually allows them to adapt to life on land.
The main Amphibians we know in this country are Frogs, Toads and Newts. The first two are fairly similar, frogs are smooth and moist and toads are dry and warty. The newt looks more like a lizard! Britain has 3 different types of newt. These are:
- Crested Newt – the largest and rarest of the species which has a crest
- Smooth or Common Newt – this has an orange belly with dark spots on its throat
- Palmate Newt – this has a yellow belly and no spots
- Firstly, it’s important to remember that all newts are partly protected species and the crested newt is fully protected so you should never remove them from the wild to bring back home to your garden.
Over the last few years there has been a decline in all of them due to changes in the environment farming etc. there has been massive losses of ponds and lakes across the whole of Britain and the amphibians are having a rather hard time of it. Frogs have made an inroad into our artificial garden ponds. Toads have been slower and less certain to use them as they prefer large deeper water than what is normally found in garden ponds. Newts prefer standing water with plenty of weed like lake margins, ditches and ponds.
The spawn, which are the eggs ,are also easy to distinguish as the toad lays theirs in a chain , the frog in a clump and the newt wraps each egg singly in a water plant leaf.
Usually, about 6-21 days (average!) after being fertilized, the egg will hatch into tadpoles. The tadpole at this point consists of poorly developed gills, a mouth, and a tail. It’s really fragile at this point. They usually will stick themselves to floating weeds or grasses in the water using little sticky organs between it’s’ mouth and belly area. Then, 7 to 10 days after the tadpole has hatched, it will begin to swim around and feed on algae. After about 4 weeks, the gills start getting grown over by skin, until they eventually disappear. After about 6 to 9 weeks, little tiny legs start to sprout. The head becomes more distinct and the body elongates. By now the diet may grow to include larger items like dead insects and even plants .The arms will begin to bulge where they will eventually pop out, elbow first. After about 9 weeks, the tadpole looks more like a teeny frog /toad with a really long tail. It is now well on it’s way to being almost full-grown! By 12 weeks, the tadpole has only a teeny tail stub and looks like a miniature version of the adult. Soon, it will leave the water, only to return again to lay more eggs and start the process all over again!
The eggs hatch in around two or three weeks to produce small, almost transparent yellowish larvae with long, thread-like gills, which attach themselves to plants for the first few days of life, becoming free-swimming later. Feeding on algae and other water plants at first, they gradually become carnivorous, eating water-fleas and other small insects and grow their legs in reverse order to frogs and toads, their forelimbs appearing first. The young, now having grown fully developed lungs, leave the water in August or September and search out a suitable place to spend the winter, usually under moss or in holes in the ground. Young newts will not return to the water again until they are sexually mature in two or more year’s time if they survive. Life is not easy
They are all one of a gardener’s best friends in the constant battle against slugs and other pests so we need to look after them.
Thanks to the people in the village involved in “The Toad Watch” …….they are so useful to us all and need all the help we can give them! See the ‘Toads’ webpage for information about Toadwatch. If you are interested why not offer to help next year!