How many frogs do we eat?

20 01 2009

IMG_20130209_141200A paper that my colleagues and I wrote soon to appear in Conservation Biology describes the massive worldwide trade in frog parts for human consumption. I bet you had no idea…

This report from New Scientst:

Are frogs being eaten to extinction? We’re used to hearing about how disease, climate change, and habitat degradation are endangering amphibians, but conservationists are warning that frogs could be going the same way as the cod. Gastronomic demand, they report, is depleting regional populations to the point of no return.

David Bickford of the National University of Singapore and colleagues have called for more regulation and monitoring in the global frog meat market in order to avoid species being “eaten to extinction”.

Statistics on imports and exports of frog legs are sparse as few countries keep track of the amount of meat harvested and consumed domestically.

According to UN figures, global trade has increased in the past 20 years. France – not surprisingly – and the US are the two largest importers; with France importing between 2500 and 4000 tonnes of frog meat each year since 1995.

But although frog legs are often thought of in the West as a quintessentially French dish, they are also very popular in Asia.

Bickford estimates that between 180 million to over a billion frogs are harvested each year. “That is based on both sound data and an estimate of local consumption for just Indonesia and China,” he says. “The actual number I suspect is quite a bit larger and my 180 million bare minimum is almost laughably conservative.”
Local depletion

Even top French chefs may be unaware of where their frogs are coming from. Bruno Stril, teaching chef at the Cordon Bleu school in Paris, France, is unsure where his suppliers source their frog legs. “I would like for them to come from France,” he says. But he expects that most of the meat comes from other countries.

Stril is on the right track. Indonesia is the world’s largest exporter of frog meat, exporting more than 5000 tonnes of frog meat each year, mostly to France, Belgium and Luxemburg.

Bickford and colleagues say European kitchens initially found their own supplies in the surrounding countryside, but the fact that they are now importing from Asia suggests local populations were over-harvested. This, they say, could be a sign that frog populations, like many fish populations, will be harvested to near extinction.

“Overexploitation in the seas has caused a chain reaction of fisheries collapses around the world,” the researchers write. “This experience should motivate better management of other exploited wild populations.”
Anonymous legs

James Collins, of the World Conservation Union, says the Californian red-legged frog offers some evidence for the theory. This species was first harvested for food in the 19th-century California gold rush and eventually the population began to crash.

However, Collins cautions that “at the moment we have no data indicating that commercial exploitation has led to the extinction of any amphibian species.” He says the Bickford team’s evidence is worrisome, but inconclusive.

Most harvested frogs are skinned, butchered and frozen before being shipped overseas. This makes it difficult to know exactly what species are being killed. Indonesia is thought to mostly export crab-eating frogs, giant Jana frogs, and American bullfrogs. How much meat is consumed within Indonesia’s borders is also something of a mystery. Some studies suggest it could be between two and seven times what is exported.

“There are a hell of a lot of frogs being eaten,” says Bickford. “Much more than most people have a clue about.”

Original article soon to appear: Warkentin, IG, D Bickford, NS Sodhi, CJA Bradshaw. 2009. Eating frogs into extinction. Conservation Biology DOI: 10.1111/j.1523-1739.2008.01165.x

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18 responses

13 11 2009
Crap environmental reporting «

[…] a very friendly American food journalist yesterday, I expected a reasonable report on the issue of frog consumption because, well, I explained many things to her as best I could. What was eventually published was […]


20 10 2009
Aaron Lobo

I enjoyed this paper, but there’s certainly a need for more local/regional studies. I come from Goa in India where frogs have been traditionally consumed for generations though the markets were small and rather non-existent.

However, now because of the booming tourist industry, the demand for frog legs ( considered exotic nad sold under the name – jumping chicken) is commonly available in several restaurants in the state. Though illegal, the rampant harvest still continues and has now become indiscriminate – capturing breeding individuals, gravid females and undersized individuals to meet the demand of the restaurants. Sadly there’s no data going back in time, however attempting to obtain logs in the form of receipt books from restauranteurs (where scarcely possible) may help trace such temporal patterns.

Enjoy reading your blog,


10 08 2009
Continuing saga of the frogs’ legs trade «

[…] come out online in Conservation Biology – Eating frogs to extinction (Warkentin et al.). I blogged about the paper then (one of ConservationBytes’ most viewed posts) that described the magnitude of the global […]


1 03 2009

I think this Ruslan Novitsky missed the point:

Scientist wants to fight financial crisis with frogs


9 02 2009

The paper ‘Eating frogs to extinction‘ is now available online, or email me here for a PDF reprint.


7 02 2009
Geoff Russell

A) 6.7 billion people + moral acceptability of eating frogs => high demand,
B) ease of frog exploitation => policing impossible
C) A + B => extinction(s)

Wildlife is simply an unscalable food source. Consider fishing, which is basically a hunting activity. It only supplies 1% of global calories, mainly to the wealthy, many of whom have been sold on the heart health benefits of omega-3s (which are not supported by the only
extensive meta-analyses of the data

A reasonable proportion of hunters/fishers don’t have much respect for laws (or welfare), hence compliance is a huge issue.

Back when I attended duck shoots at Bool Lagoon in the 90s, every time Freckled ducks showed up during shooting, they were shot. We picked them up regularly and could generally tell when a shooter had shot one … any time a shooter made no effort to retrieve a duck which was clearly downed, there was a good chance that it wasn’t a legal kill, perhaps a Freckled, perhaps a coot (the old hunters call them “eye openers” — think about it), perhaps he already had a bag (unusual, but occasionally this happened).

A nice study in the late 80s in Canada (Nieman et al, Monitoring hunter performance in prairie Canada’, Transactions of the 52nd North American Wildlife and Natural Resources Conference 52,233–245.) observed shooters from hidden hides, then interviewed them. The result: hunter estimates of cripple rates were low, and about 12% of hunters broke licence conditions.

Read some of the articles on the following site about illegal fishing:

Illegal fishers are resourceful and cunning and they will satisfy a demand where it exists and the money makes the risks worth taking.

Why does the kangaroo industry need such a fancy system of tags to prevent (or attempt to prevent) illegal activities?


3 02 2009

I’ve just confirmed that the paper Eating frogs to extinction will be available online on 9 February 2009. This link should take you there when it becomes active next week.


28 01 2009

Good to see that there is much more interest, it is about time we consider other factors that, like you said have been under the radar! Thanks for linking me to this blog, from now on I will be a frequent visitor.
Mucho gusto,


27 01 2009
Corey Bradshaw

Thanks, but not doing much with crocs these days.


25 01 2009
Neil Ellis

Oh and do you want any help with the Crocs?


25 01 2009
Neil Ellis

That is what I had feared the case would be, Thanks very much for the references, they were very interesting. So it looks like eating frogs will just have be banned! Ah well what a shame! I just hope the interest in your work and the fate of Amphibians continues to increase as so often all the general public hear about are the “charismatic” animals that conservation groups and charities use as flagship species, which I know helps indirectly as if you save a habitat for Rhinos you save it for the entire biological community. It would be nice to see a few more frogs, crocs and inverts on posters and heading up publicity campaigns.
cheers Neil


24 01 2009
Corey Bradshaw

Thank you, Neil. I am personally amazed at the interest – but I’m happy it has been taken up so well considering our principal aim was to make people aware of the problem.

As for farming, the problem is principally that many are bastions of amphibian pathogens just waiting to break out and infect wild populations. Some good references on this issue include:

– Garner, TWJ et al. 2006. The emerging amphibian pathogen Batrachochytrium dendrobatidis globally infects introduced populations of the North American bullfrog, Rana catesbeiana. Biology Letters 2:455-459

– Fisher, MC & TWJ Garner. 2007. The relationship between the emergence of Batrachochytrium dendrobatidis, the international trade in amphibians and introduced amphibian species. Fungal Biology Reviews 21:2-9

– Garner, TWJ et al. In press. The amphibian trade: bans or best practice? Ecohealth

While many farms exist, many have failed for disease and issues of regarding poor husbandry. A colleague of Trent Garner apparently has evidence that frog farms in China also harbour B. dendrobatidis and ranavirus.

Although improvements can be made, farming itself won’t fix the problem.

CJA Bradshaw


24 01 2009
Neil Ellis

Thanks for bringing this to the worlds attention, it needed to be done.
What I just can’t understand is why in this day and age the restaurant trade still allows the collection of frogs from the wild, when farming would be a much better option, When you consider that only 3-10% of amphibian eggs survive to reproduce in the wild its madness, as they are so fecund just a few breeding pairs could provide a farm with hundreds of thousands of frogs without harming the wild populations at all. Its as crazy as the American Fish and Wildlife service killing off wild endangered burmese pythons that have been released and are now breeding in the Everglades rather than catching them and returning them to Asia, its madness, I posted on my blog about it.
Cheers Neil


22 01 2009
21 01 2009
Corey Bradshaw

Some recent media/blog hits on this one:

BBC News – A billion frogs on world’s plates
The Australian – Humans eating frogs into extinction – One billion frogs harvested as food per year
Science Alert – Delicious frogs heading for extinction
News24 (South Africa) – Frogs about to croak
Economic Times (India) – Frogs in danger of being ‘eaten to extinction’
Sky News – Frogs on their last legs – study
ScienceDaily – Frogs Are Being Eaten To Extinction, Experts Say
PerthNow – Humans eating frogs into extinction
ABC – Appetite for frog legs leading to extinction
Animals in the News Blog – Humans eating frogs into extinction
Nerdy Science Blog – Human Stomach is the Graveyard of the Frogs
Geek Archipelago – Frogs don’t have it easy
Aquarium and Terrarium Blog – Frog legs anyone?
Not Extinct Yet – Endangered Eating: Frog Legs
Food Flashes – Will frog legs have legs?
Treehugger – Humans are eating too many…frogs – Frogs on their last legs: study

See also here for updates


21 01 2009
Corey Bradshaw

Glad to hear it, but lines like:

“L’attitude du New scientist est irresponsable. Il y a bien assez de guerres en ce moment pour ne pas jeter de l’huile sur le feu. Qu’espèrent-ils en remettant en cause notre patrimoine gastronomique ? Une nouvelle guerre de cent ans ?”

(Translation: New Scientist’s attitude is irresponsible. There are quite enough wars on at the moment to be adding fuel to the fire. What do they hope to gain by challenging our gastronomic traditions? A new 100 Years War?)

is a little inflammatory, n’est-ce pas? With all the conservative, money-grubbing, anti-environmental sentiment out there at the moment (just read a few of the comments to some of my blog posts about oil palm), you can forgive me for believing your rhetoric was sincere.

Il faut peut-être trouver un autre moyen de rigoler, croyez-vous?


20 01 2009

dear Corey Bradshaw
This article I wrote was of course a joke. I don’t really care about eating frogs… which I, by the way, never do.
Please read -and understand- an artible before criticizing it.


20 01 2009
Corey Bradshaw

Have a read of this:

Amazing – talk about missing the point. Nothing like wading in without even looking where you’re going (he could have waited 2 weeks and actually read the article). Turning this issue into a “oh, we poor French are so abused by our English neighbours” is about as relevant as de Gaulle in world politics and as contemporary as Henry VIII – welcome to the 21st century, mate.

If anything, this is more an attack on Indonesians than the French – wake bloody up! The issue isn’t about your precious culinary history; it’s about the entire amphibian taxon getting nailed from every possible angle.


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