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You get home after a hard day, sit down and put the TV on. Almost certainly during
the course of the evening, when you get up to make a cup of tea in an advert break, three
popular frogs will be making an appearance. I am
of course referring to the `Bud' — `Weis' — `Er' frogs. The fact that this loveable little
creature has made its debut in the advertising
business is a testament to its popularity. The
beauty of the common frog is the diversity of the
species, and the ease of access to them that people in Britain have. The lifestyle and
life-span of this endearing animal is a fascinating
display of metamorphosis, and an intriguing mixture of vulnerability and adaptability. |
The Frog's Life-cycle |
| A tiny egg the size of this letter `O' is how a frog begins life. Within ten days the egg
will have doubled in size, and after fifteen days,
a close inspection of the egg would reveal a tiny tadpole inside, ready for hatching. After
three weeks, the fully formed tadpole has begun
its second transformation — the metamorphosis into a froglet — and already the first
frontal digits have begun to form. Its tail expands
into what appears to be a fin, and by ten weeks
its once round head begins to distort into the
more angular shape of a frog's. By week thirteen
it more closely resembles a frog than a tadpole, but still has the long fin-tail. |
Hopposite sexes: female frogs are generally bigger than males, and hibernate
separately: females on land, males in water.
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What a blinking nuisance! A frog cannot swallow without closing its eyes.
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It is at this time that it is most at risk from predators, as it can neither swim with the
efficiency of a tadpole nor leap with the prowess of a frog. But in the next three weeks the
froglet will complete its metamorphosis. Its tail
disappears and a tiny frog — about the size of
a five-pence piece— begins its journey into
adulthood. It enthusiastically consumes food in a bid to amass body weight before the
winter sets in. |
Why Survey Frogs?
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| Although they seem very prolific and widespread, we should not take frogs for
granted. Recently they have appeared in the UK
Biodiversity Steering Group's list of globally
threatened or declining species. Because they breathe through their skin, they are
extremely susceptible to deformities in areas where
pollution is high. Artificial interference in frog
numbers is also very damaging, whether by deliberate introduction or destruction of
frogspawn. This is why we must continue to study
frogs and update our information. It is vitally
important to gather as much information as possible on the size, colour, frequency and
living conditions of our common frogs. Filling in
the enclosed survey forms will help us achieve this. |
Here's something to chew on: frogs have teeth; toads don't.
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Frogs and Ponds
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Some food for thought: in 1837, the Edible Frog was introduced into mainland
Britain from France by Dr A Smith.
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Although it is a common worry that garden ponds have excessive amounts of spawn,
the difficult early stages of the froglet's life
mean that only a tiny percentage of the potential frogs survive to maturity. |
| Having said that, in one of Sheffield Wildlife Trust's most recent pond surveys, people
reported that over 90% had frog life. This is why frogs are an excellent and accessible
species to study. They are generally happy to live
in garden ponds as well as on wild wetlands, and are totally harmless to humans and
domestic pets. Frogs vary greatly in colour —often
green, grey, yellow or reddish-brown— and their
skin is usually mottled with dark patches.
Recently there has been an increase in the number
of pink albino frogs being reported. This is
thought to be caused by the effects of pollution
in ponds, and of global warming. |
A leap of imagination? According to the Guinness Book of Records, an American
Bullfrog jumped 19 feet 3½inches in front of a
crowd of 65,000 people at the 1966 Frog Olympics in South Africa!
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