Friday, November 11, 2011

The wolf and the wild boar

An ecological parable from the beech forests of northern Japan

Reading Brett Walker's book on the Japanese wolf led me to the case of another vanished beast. You won’t find any wild boar in Japan’s snowy Tohoku region today. With their short legs and their need to dig up fodder from the forest floor, the animals can’t live through winters where deep snow lies for seventy days or more.

In the past, those northern winters must have been even colder and snowier. Yet records from the Edo period show that wild boar once roamed as far north as Aomori, right at the top of Tohoku. In fact, so many of them were raiding farmers’crops around Hachinoe in 1749 that they caused a famine during which 3,000 people starved to death.

Despite all efforts to wipe them out, wild boar continued to thrive in northern Japan until the nineteenth century. Then, at some point in Meiji times (1868-1912), they went into decline. The last Tohoku boar was hunted down in 1907. This was just two years after the demise of Japan’s last wolf.

Was there some link between the fates of wolf and boar? The question had to go unanswered until the 1990s, when ecologists in Poland made studies of the country’s Carpathian mountains. This region resembles Tohoku in its rolling beech woods, cold winters, and deep snow cover.

Lynx, wolves and wild boar still roam the Polish forests. Unsurprisingly, the researchers found that the wild boar often furnish lunch for the wolves. So much so, that when the wolf population grows, the number of boar shrinks, and vice versa.

What was less expected is that the wolf returns this favour. During the winter months, the boar can't dig through the snow and frozen ground to get fodder. So how do they survive? Seemingly, by foraging on the leftovers from wolf and lynx kills.

That might explain how the wild boar of Tohoku endured the long winters. It also suggests why they died out in the north country. Traditionally, the boar’s disappearance was explained by swine cholera, a disease brought into the country with imported pigs when Meiji Japanese acquired a taste for tonkatsu.

Disease can't be the full story, as wild boar have survived in warmer parts of Japan. In Tohoku, however, the boar suffered a double whammy. First, they lost their winter food supply when the wolf went extinct –then the absence of their main predator meant that sick or weak wild boar continued to spread the swine cholera unchecked.

The secret liaison of wolf and boar is just one of the web of dependencies that makes up a forest. Pull on one thread, such cases suggest, and the ecosystem may unravel somewhere completely unexpected. What hidden connection will those northern woods next reveal?


Hito wa naze yama ni noboru no ka?, Volume 103 in the Taiyo Bessatsu: Nihon no Kokoro series (Heibonsha, 1998) - chapter on the Japanese wolf

Picture of wild boar from Wikipedia

And see Sapphire Sky for an update on the urban wild boars of Kobe ...


☆sapphire said...


The book sounds very interesting. I'd like to read it. Thanks for sharing.

As for wild boars, they are now thriving in various parts of Tohoku and I've heard that people there have lots of problems about how to deal with them. For example:

As you say, "the boar can't dig through the snow and frozen ground to get fodder", originally, there were few of them in North East Japan. But really surprisingly, there have been many sightings of the animal in recent years in the Ouu(奥羽)mountains and other mountains in Tohoku. It looks like wild boars extend the range of their inhabitation. Maybe because of global warming??!

In the Rokko Mountains in Kobe, there are lots and lots of them. You can even see them in the city.
The boars in the photos were roaming in the river near my Mom's house. We don't shoot them; just let them live in Kobe and we are prohibited from feeding them by law(some people in Kobe actually feed them secretly so..)

Project Hyakumeizan said...

Sapphire: many thanks for your most interesting update. Yes, the wild boar has probably extended its range northwards since my sourcebook was published in 1998. The exact wording of the article is as follows:- 東北、北陸地方のほとどの地域にイノシシは分布していない。

My impression - from a few visits to Japan and accounts from friends - is that a lot has changed in the mountain ecosystem since the 1990s - warmer winters, deer on the rampage, monkeys etc moving higher, bears more and more in conflict with humans etc. Whether this has to do with climate change or not is a question that some cho-hakase will have to deal with. If only the mountaineer scientist Imanishi Kinji were still around...

I have to confess, I've never seen an inoshishi in the wild, either in Japan or the European Alps. But I've seen the trenches they can dig in farmers' fields. Not surprising that they can cause famine.

On the other hand, I've heard that inoshishi-nabe (イノシシ鍋) is delicious. Maybe we should all develop a taste for it .....

sunnybeauty said...

In Hokuriku, there seem to be a lot of them. Every time I go to my local mountains, I see they've dug up the grounds looking for some delicious roots of trees and plants (?). Quite naughty of them... Also, there are many mud baths they've made. I've never seen them, though, because they are nocturnal.

They come down to villages, too. A friend of mine, who used to plant cosmos in the fields according to his father's will, had to give up his cosmos garden because wild boars made the field their hiding place.

A few years ago, when I came down from Mt Dainichi in Gifu, I saw many of them caught in cages in a village in Hirugano. They were huge. I wouldn't want to be hit by them. However, I do not want to eat them, either. Somehow, I identify myself with them...

hanameizan said...

Wild boars may look stupid, but they know exactly when potatoes are perfectly ready to eat, and will clear out every last trace the night before you intend to harvest, as my neighbor found out this year.

Project Hyakumeizan said...

Rooting up a sweet potato patch just before harvest? What boarish behaviour - this could only have been the work of a local gang of boar-so-zoku, I guess...