Ranavirus: It's a frog's life

As a new virus cuts a swathe through their numbers, Gillian Orr discovers that we are only starting to unlock the secrets of these alluring amphibians


Sad news: last week scientists revealed that the number of common frog populations has fallen by more than 80 per cent because of a virus spreading through the UK. Ranavirus is thought to be new to this country and the symptoms include the haemorrhaging of internal organs and skin ulcerations. This frog plague is a disaster for a species that is as fascinating as it is mysterious.

From more 5,000 known species of frogs, the world's smallest is called Microhyla nepenthicola. The adult males of the amphibians range in size between 10.6mm and 12.8mm, barely bigger than a pea. They were discovered by scientists living in and around carnivorous plants in Borneo earlier this year.

Scientists believe that the largest frog ever was the Beelzebufo ampinga, which lived about 65 million years ago, at the same time as dinosaurs. It was as large as a beach ball and weighed about 10lb. A palaeontologist unearthed the fossils of the frog in Madagascar and it took 15 years and 75 fossils to put together an accurate reconstruction.

Many frogs contain poison and toxins that can be harmful to humans. The most dangerous frog is the phantasmal poison dart frog, found in Ecuador. Although very pretty and only ranging in size between 1-4cm, they have one of the strongest toxins found in frogs.

It's not all bad though: because these frog toxins are extraordinarily diverse, they have raised the interest of biochemists. The alkaloid epibatidine, a painkiller 200 times more potent than morphine, is found in some species of poison dart frogs. Other chemicals isolated from the skin of frogs may offer resistance to HIV infection.

The skin of frogs contains powerful germ-fighting substances because of the hostile environments they exist in. A substance isolated from the skin secretions of the Foothill Yellow-legged Frog (once common in California and Oregon but now facing extinction) looks likely to be able to kill the methicillin-resistant Staphylococcus aureus bacteria, more commonly known as the hospital superbug, MRSA.

Although we tend to associate the eating of frogs with France, frogs are also popular on dinner plates in Asia. According to UN figures, the global trade in frogs has increased in the past 20 years. France and the US are the two largest importers; with France importing between 2,500 and 4,000 tonnes of frog meat each year.

We might enjoy eating frogs but some frogs also enjoy eating each other. The Lechriodus species of frog, which is found in Australia and New Guinea, are commonly known as cannibal frogs, for obvious reasons. It is common for frogs to eat tadpoles as well.

The main reason for frogs to call is to attract a mate and females generally prefer louder calls, because they indicate a bigger, stronger male. Frogs will also use their call to emit a distress signal. Some frog calls are so loud they can be heard a mile away.

The degree to which a frog's toes are webbed depends on their habitat and how much time they spend in water. The African dwarf frog lives nearly all of its life underwater and has fully webbed toes. The Australian green tree frog, which rarely goes near water, has only very slightly webbed toes.

Discovered in 1852 in Ecuador, glass frogs are a family of frogs that are green in colour over most of their bodies but have translucent chests, allowing you to see their internal organs and beating heart. Glass frogs have a unique pigment in their skin that reflects the same infrared radiation as plants, probably to allow them to conceal themselves.

Surely the most famous amphibian in the world is Kermit the Frog, who, in a career spanning 55 years, has starred in dozens of films, television shows, and adverts; received a star on the Hollywood Walk of Fame; accompanied Lady Gaga to the MTV Music Video awards and even addressed the Oxford Union.

John Travolta is a qualified airline captain and employed the pilot with his company, Alto
people'That was the lowest I’d ever felt'
Life and Style
healthIt isn’t greasy. It doesn’t smell. And moreover, it costs nothing
Jonas Gutierrez (r) competes with Yaya Toure (l)

Newcastle winger is in Argentina having chemotherapy

Arts and Entertainment
Emma Thompson and Bryn Terfel are bringing Sweeney Todd: The Demon Barber of Fleet Street to the London Coliseum

Returning to the stage after 20 years makes actress feel 'nauseous'

Have you tried new the Independent Digital Edition apps?
peopleThe Times of India said actress should treat it as a 'compliment'

Watch this commuter wage a one-man war against the Circle Line
We are phenomenally good at recognising faces; the study showed that humans have been selected to be unique and easily recognisable

Human faces unique 'because we don't recognise each other by smell'

Arts and Entertainment
You've been framed: Henri Matisse's colourful cut-outs at Tate Modern
artWhat makes a smash-hit art show?
Home body: Badger stays safe indoors
lifeShould we feel guilty about keeping cats inside?
A male driver reverses his Vauxhall Astra from a tow truck

Man's attempt to avoid being impounded heavily criticised

Arts and Entertainment
Blossoming love: Colin Firth as Stanley and Emma Stone as Sophie, in 'Magic in the Moonlight'

Colin Firth and Emma Stone star together in Magic in the Moonlight: Woody Allen's 1920s romance

Arts and Entertainment
US pop diva Jennifer Lopez sang “Happy Birthday” to Gurbanguly Berdimuhamedow, president of Turkmenistan
musicCorporate gigs become key source of musicians' income
Arts and Entertainment
While many films were released, few managed to match the success of James Bond blockbuster 'Skyfall'
filmsDaniel Craig believed to be donning skis as 007 for first time
The Guildhall School of Music and Drama is to offer a BA degree in Performance and Creative Enterprise

Arts and Entertainment
Pulp-fiction lover: Jarvis Cocker
booksJarvis Cocker on Richard Brautigan
Arts and Entertainment
Robin Thicke and Pharell Williams in the video of the song, which has been accused of justifying rape
music...and he had 'almost no part' in writing it
Life and Style
The findings suggest that some of the genetic factors which influence birth size may play a part in influencing an infant’s mental development
health...while smaller babies have greater schizophrenia risk, study claims
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

March On Cancer™ - Local Marketing and Promotions Volunteer

This is an unpaid voluntary role.: Cancer Research UK: We need motivational vo...

SEN Coordinator + Teacher

£1 per day: Randstad Education Leeds: Job Purpose To work closely with the he...

Maths Teacher - Evening session

Negotiable: Randstad Education Birmingham: I am looking for a qualified experi...

Teaching Assistants

£50 - £85 per day: Randstad Education Preston: Rapidly developing and growing ...

Day In a Page

Mystery of the Ground Zero wedding photo

A shot in the dark

Mystery of the wedding photo from Ground Zero
His life, the universe and everything

His life, the universe and everything

New biography sheds light on comic genius of Douglas Adams
Save us from small screen superheroes

Save us from small screen superheroes

Shows like Agents of S.H.I.E.L.D are little more than marketing tools
Reach for the skies

Reach for the skies

From pools to football pitches, rooftop living is looking up
These are the 12 best hotel spas in the UK

12 best hotel spas in the UK

Some hotels go all out on facilities; others stand out for the sheer quality of treatments
These Iranian-controlled Shia militias used to specialise in killing American soldiers. Now they are fighting Isis, backed up by US airstrikes

Widespread fear of Isis is producing strange bedfellows

Iranian-controlled Shia militias that used to kill American soldiers are now fighting Isis, helped by US airstrikes
Topshop goes part Athena poster, part last spring Prada

Topshop goes part Athena poster, part last spring Prada

Shoppers don't come to Topshop for the unique
How to make a Lego masterpiece

How to make a Lego masterpiece

Toy breaks out of the nursery and heads for the gallery
Meet the ‘Endies’ – city dwellers who are too poor to have fun

Meet the ‘Endies’ – city dwellers who are too poor to have fun

Urbanites are cursed with an acronym pointing to Employed but No Disposable Income or Savings
Paisley’s decision to make peace with IRA enemies might remind the Arabs of Sadat

Ian Paisley’s decision to make peace with his IRA enemies

His Save Ulster from Sodomy campaign would surely have been supported by many a Sunni imam
'She was a singer, a superstar, an addict, but to me, her mother, she is simply Amy'

'She was a singer, a superstar, an addict, but to me, her mother, she is simply Amy'

Exclusive extract from Janis Winehouse's poignant new memoir
Is this the role to win Cumberbatch an Oscar?

Is this the role to win Cumberbatch an Oscar?

The Imitation Game, film review
England and Roy Hodgson take a joint step towards redemption in Basel

England and Hodgson take a joint step towards redemption

Welbeck double puts England on the road to Euro 2016
Relatives fight over Vivian Maier’s rare photos

Relatives fight over Vivian Maier’s rare photos

Pictures removed from public view as courts decide ownership
‘Fashion has to be fun. It’s a big business, not a cure for cancer’

‘Fashion has to be fun. It’s a big business, not a cure for cancer’

Donatella Versace at New York Fashion Week