Frequently asked questions about frogs

Here are some of the questions we have been asked about frogs.

Why do frogs keep trying to get in my front door and what can I do?

Well when frogs are migrating to their breeding pools in spring they tend to move in straight lines and try and tackle any obstacle that gets in their way - and a house is just another obstacle. They don't know you live there an will try any route to go through it even if that means coming in the front door. One possible way to solve the problem is to move them to the other side of the house and they might head away from your home on towards their choosen pond!

A number of people have contacted the office about what to do about large quantities of frog spawn in their garden ponds?

In general we would recommend - and the law dictates - that the spawn should be left where it is. Remember that a very high percentage of the tadpoles will never make it to the froglet stage - they will be get sick or be eaten by other tadpoles, water beetles, water spider and a host of predators. So even though you start with a lot of spawn you won't ever end up with that number of froglets - and even these will mostly die - so it is important to start with a relatively big population of frog spawn in the spring.

An exception to this rule - provided you are prepared to break the law - is a pool with ornamental gold fish or koi. These are voracious feeders and the chances of tadpoles surviving are extremely slim. In such a case you might

* get rid of your fish and have a frog friendly pond or

* transfer the spawn to a pool (maybe a neighbour) which is fish free, is established with plenty of plants and has a gently sloping edge to allow the froglets to escape later in the year or

* you might also transfer the spawn to a pool in the wild that you know has tadpoles in in already.

Move the spawn in a large bucket containing some of the pools own water (not tap water) as soon as you remove it from your pond.

How can frogs jump so high?

Frogs are able to jump such great distances because of the powerful, well developed muscles in their hind legs. Also the length of their hind legs gives them a spring. It is this combination of spring and power that fuels the frog's leap.

Can a frog breathe underwater indefinitely and not drown?

Frogs are equipped to breath underwater and can do so indefinitely, however, a frog cannot feed underwater and so must journey onto land in order to hunt for prey and to breed.

What is the mating process for frogs?

Males arrive at the breeding pond first and begin a chorus of croaking. This attracts the females. Once the females arrive the males jump onto the backs of the females and cling on with their nuptial pads. This position is called amplexus. The female eventually lays her eggs into the water. Simultaneously the male releases his sperm into the water and on to the eggs in order to fertilise them. The fertilised eggs sink in the water and the jelly coat swells as it takes in water to protect the embryos. The spawn then rises to the top of the water.

How large are frogs eggs?

Frog eggs are approximately 2-3mm in diameter, and a frog can lay about 2,000 eggs at a time.

What is the biggest type of frog?

The biggest species of frog recorded to date is the Goliath frog of Cameroon, West Africa. These frogs can grow up to 1 foot in length.

What are a frog's natural enemies?

The natural enemies of frogs in Ireland are herons, gulls, ducks, hedgehogs, badgers, rats, stoats, and foxes.

Are there any frogs which can live their whole larval stage without water?

One example of a tadpole which does not live in water is that of the Phyllobates species of South America. The tadpoles live on their father's back until they have reached a highly developed stage. An extreme short cut in the life history is shown in a few species. For instance, Gasterotheca eggs are laid in a brood pouch on the female's back.

How do frogs feed and digest their food?

Frogs feed using their long tongue. The frog flicks the tongue out at high speed and snaps up whole invertebrates. The frog has numerous, minute cone teeth around the edge of its jaw and two patches of vomerine teeth on the roof of its mouth to prevent the prey from escaping. The prey is then squashed between the tongue and the eyeballs (which are drawn down inside the head). The food is then digested through a simple digestive system.

Why do tadpoles breathe in water, and frogs in air?

Tadpoles are only equipped with gills like fish and so breathe through water. When they undergo metamorphosis they develop lungs, like land animals, and so breathe on land. However, because frogs are amphibians they are able to breathe through their skin while under water.

How did frogs evolve?

The amphibians were the first group of vertebrate animals to make a serious attempt of life on land. Their history is long and complex from a fish like ancestor to the three groups of amphibians which exist today, the Anura (frogs and toads), the Urodela (newts and salamanders) and the Apoda (worm like animals caecilians).

To trace the origins of amphibians we must go back 350 million years to the Devonian period, a time of seasonal droughts and dry periods. Prototype amphibians are thought to have arisen from a fish-like ancestor related to modern coelacanths. These ancient fish had primitive lungs and a skull structure resembling that of later amphibians. They were probably capable of surviving through periods of drought.

There are considerable gaps in our knowledge of modern forms, but we do know that during the Carboniferous period hundreds of different amphibian forms roamed the swamps. Apart from caecilians modern amphibians lost their fish-like scales and developed a soft skin. The body was raised off the ground by development of a skeleton and a strong muscle system. The skull lost its rigid connection with the pectoral girdle and the hind legs became well developed for swimming and jumping.

Whatvis the furthest a frog can jump and what is the species?

The south American Sharp-nosed frog has the world record jump measured at 10.3 metres (recorded in 1989). This was done by a South American Sharp-nosed Tree Frog. Does anyone out there dispute the record?

A common Irish frog can jump up to 7 times its own length.

How many known species of frogs and toads are there in the world?

There are 2,500 species which live a variety of habitats from swamps and marshes to mountain streams and deserts. New species are being discovered all the time as rain forests are being penetrated further every year. In Ireland there is only one species of frog - The Common Frog (Rana temporaria) - and one species of toad - The Natterjack Toad (Bufo calamita). The Natterjack Toad is only found in Kerry and at the Raven Point in Co Wexford, while the Common Frog is widespread in Ireland.

What is the difference between a frog and a toad?

Toads are only found in Co. Kerry, they have warty dry skin and tend to walk on all 4 legs rather than hoping. Frog are found all over the country, they have a smooth wet skin and jump a lot.

How long do frogs live?

Captive common frogs have been known to live for 12 years. Some frogs have been known to live up to 20 years but few wild ones live this long.

How long does it take for spawn to become a frog?

Frogspawn turns into tadpoles after about 10 days and it takes another 12-14 weeks before the tadpoles turn into froglets.

Where do frogs go in winter?

Frogs are cold blooded animals so their body temperature drops as the temperature drops. For this reason frogs have to hibernate and they do this at the bottom of ponds, on hillsides or in other places.

How many fingers does a frog have?

Frogs have four fingers on each of their front legs and five toes on each of their hind legs.

What Irish habitats do frogs occur in?

Frogs live anywhere it's damp, especially in bogs .

What do frogs eat?

Tadpoles start life as vegetarians but after 7 weeks they start to eat insects. Frogs eat mainly insects and worms but basically they will eat almost anything with a pulse.

Why do frogs croak?

Usually only male frogs croak. They do this during the breeding season to attract female frogs and to warn away other male frogs.

How do frogs change colour?

Frogs change the colour of their skin by expanding and contracting three layers of pigment cells in the skin.

How can you tell the difference between a female and male frog?

It is easy to tell whether a frog is male or female during the breeding season (February/March). During this time the male develops dark pads on his forelimbs called nuptial pads. Also during this time the skin of the female becomes rough to the touch, so that it is easy for the male to identify a female. At other times of the year it is more difficult. Generally males are slightly larger, and tend to have longer digits on their forelimbs. Another difference is that the male croaks, and the female doesn't.

What is an amphibian?

Most amphibians start life in the water as tadpoles, but as adults they can move about on land and breathe air so they spend less time in the water. Amphibians can breathe through their skin and are cold blooded creatures. Frogs, toads, newts and salamanders are all types of amphibian.

How many species of frog occur in Ireland?

Only one -the Common Frog or Rana temporaria in latin.