Seasonality in food items has been steadily eroded in today's ever-more globalised world. Most fruits and vegetables are available year round, and constant accessibility has, in turn, diminished beliefs about certain foods being consumed only at certain times of the year.

In a culture as old and entrenched as that of China, however, some habits and preferences have held firm.

The most obvious involve foods believed to be "heating" or "cooling" to the body during digestion, and therefore appropriate (or not) to certain seasons. With the gradual change in the weather, traditional "heating" items are disappearing for another year. Mutton is one and, as we've entered the Year of the Snake, that item will soon disappear from menus for several months, too.

A steaming bowl of snake soup - made to various recipes - is a popular winter warmer. Dragon and phoenix soup combines two kinds of meat - snake, to represent the dragon (and the male element), and chicken, to represent the mythical phoenix and the female side of life.

Another variant includes "lion", which is represented by domestic cat. Readily available in specialist shops in Guangzhou, and elsewhere in Guangdong province, lion and dragon soup is difficult, but - animal-rights activists take note - by no means impossible, to find in Hong Kong, if one knows where to look and who to ask.

Consuming snake is not - contrary to assumptions over-seas - a custom all Chinese share. Except in periods of famine, when all things edible were fair game, snakes and other exotic fauna were mostly eaten only in the south.

Snake bile tinctures, meanwhile, are common topical embrocations and "pick-me-up" tonics. Generally the more potent the snake, the better the alleged effect. No surprise, then, that cobra bile was commonly sold in red-light districts as a "get-me-up" for a night's anticipated adventures.

Travel accounts detailing life in Chinese cultures commonly refer to these preparations. Patrick Anderson's Snake Wine: A Singapore Episode, a classic account of 1950s Singapore, even takes the subject as its title.

Hong Kong has numerous varieties of wild snake. The vibrantly striped banded krait and the bright green, aptly-named bamboo snake are common sights in the summer months. Pythons are also numerous, as are cobras. And anywhere there is an abundance of frogs, you'll find snakes. Powdered sulphur (readily available at any hardware store) sprinkled across doorways will keep them outside.

Across cultures, snakes have historically been regarded as harbingers of good fortune or evil.

In China, a snake found in a house was once regarded as a sign of good luck. And like most symbols relating to fortunes - good or bad - in China, where widespread hunger and intermittent famine were the norm until fairly recently, such an omen was taken to refer to the supply of food.

If snakes lived in the vicinity there were, by logical extension, rats and other vermin for them to feed upon; and if there were rodents, there was obviously enough food about to attract them. And so, the reasoning went, the household must have been fairly prosperous. No rats and, therefore, no snakes, indicated a very poor family indeed.