It is said that 90 years have passed since giant African snails were first imported to Okinawa Prefecture.
The snails, one of the world’s largest of the kind, are native to East Africa, and their shells can grow to as high as 20 centimeters, with a very different appearance from snails found in mainland Japan.
They can be observed at various places in Okinawa Prefecture, including parks in residential areas.
The gastropod is unpopular among local residents and is called an alien species that shouldn’t be touched, as it damages crops and sometimes hosts rat lungworms.
Rat lungworms also infest other types of snails and slugs, and if humans are infected, it could cause meningoencephalitis.
In 2000, an American girl who went to an elementary school inside a U.S. base in Okinawa died of the disease.
Hisao Hamaguchi, head of Gosamaru Historical Materials Library in the village of Nakagusuku, has been researching the history of giant African snails, which have been regarded as a nuisance.
The snails feed on plants when they are small, and as they grow up they begin to prefer eating animal carcasses and humic substances.
There are cases in which they have lived for a long period of time without water or food.
Hamaguchi became interested in giant African snails in 2016, after seeing a picture of a snail eating a dead Ryukyu odd-tooth snake, taken by a colleague at a place where he used to work.
He said he was attracted to the snail as he was surprised to see a snail eating a snake, instead of the other way round.
Snail cultivation boom in Taiwan
According to Hamaguchi, giant African snails were first carried into Japan from Taiwan in the 1930s, when a person named Shingo Tazawa was given four of those that had been brought to Taiwan from Singapore by an engineer of the Government-General of Taiwan — the government of Taiwan under Japanese rule between 1895 and 1945.
As escargots had been sold at high prices as an ingredient for French cuisine, giant African snails were also put on sale, leading to a cultivation boom in Taiwan.
The snails were shipped to various parts of Japan and it is believed that they were first brought to Okinawa in around 1934.
However, the boom didn’t last long.
In 1936, the Japanese government banned transfers of the snails across national and prefectural borders, recognizing them as pests that destroy crops.
In Okinawa, the snails were left unchecked amid the Battle of Okinawa during World War II and bred in the wild.
Extermination efforts in the 1960s
People were apparently troubled by the strong reproductive power of the snails, as seen in numerous reports on the capturing of the gastropod published in The Okinawa Times in the 1960s.
The reports describe the snail as laying 200 to 300 eggs at one time and eating plants amounting to as much as 10% of its weight a day.
One article said that farmers “have a deep grudge” against the snails as they “eat up everything they find, ranging from gourd seedlings and tobacco leaves to leafy vegetables.”
Although they gave an extremely bad impression, the snails contributed to the people of Okinawa who ate them as a precious source of protein during the postwar period until around 1955. They were also used to feed pigs.
“They saved the people of Okinawa during the period of food shortage,” Hamaguchi said. “I hope people will regard them not only as pests that should not be touched but also as something that played an important role in society.”
The protein of the future?
The global economic cost of invasive alien species that cause biodiversity loss exceeded $423 billion annually in 2019, according to a report released last year by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), an intergovernmental body that makes recommendations based on research results worldwide.
The report says more than 3,500 invasive alien species are recorded globally, seriously threatening biodiversity and ecosystems, as well as economies, food, water security and human health.
The giant African snail is one of such species.
The report points to invasion prevention, early detection and rapid response as the most cost-effective ways to manage invasive alien species.
In order not to repeat the same mistake, it is vital not to allow invasive species to enter the country.
While it is necessary to kill invasive species to protect ecosystems, we must not forget the fact that giant African snails, as well as mongooses that are targeted for eradication in the forests in the Yanbaru region in the northern part of Okinawa Island, became recognized as alien species after being brought to the country by humans.
According to Hamaguchi, giant African snails are nutritionally outstanding, high in protein and low in fat, and some say they have potential as a protein source of the future.
Those who ate them during and after World War II said it was difficult to remove the glutinousness even after they were boiled, rubbed with salt and rinsed repeatedly.
If a good way to cook them is developed, their position might change for the better.
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