The majority of people in Vietnam live in the rice-producing regions. The Red River delta in North Vietnam is more heavily populated than the delta region of the Mekong in the south. As many as 1,000 to 3,000 people may live on one square mile of land in the Red River delta. Figures for the southern delta show between 200 to 500 people residing on one square mile of land. In the mountain regions of Vietnam, as few as five or six people may live on a square mile of land.
Hydrography
The principal river of North Vietnam is the Red River (Son Hong Ha) which begins in the Yunnan province of China and flows through North Vietnam spreading into a delta before emptying into the Gulf of Tonkin. It is sometimes called the "mother river" because its alluvium fertilizes the lands of North Vietnam. Other rivers are the Clear River (Lo-Giang) and the Black River (Da-Giang). Main streams are the Day, the River of Nam-Dinh, the Canal of Rapids and the Canal of Bamboos.
The Red River delta is joined to another, the Song Tai-Binh which is made up of the three united rivers, the Cau, Thuong, and Luc-Nam.
The best-known river in the Central region is the Perfume River in Hue province. Other small rivers abound in this area including the Ca, Ma, Gianh, Thu Bon, Tra-Khuc, and Da-Rang.
By far the most important river in the southern part of the country is the huge Mekong, which winds over 2,500 miles from the highlands in Tibet to the South China Sea. The entire delta region of South Vietnam is furrowed by many streams, tributaries of larger rivers and numerous canals which make up an excellent network for navigation and irrigation.
Some of the other rivers and streams in the south are the Dong Na (splits into the Donnai and River of Saigon); the Vam-Co and the branches of the Mekong, Tien-Giang (upper river) and the Hau-Giang (lower river).
Climate
The climate of Vietnam, just as its geography, is subject to many variations.
North Vietnam
The climate in the north is very similar to that of southern China. It is characterized by great seasonal differences in temperature, and sudden changes are not uncommon.
There are two main seasons in North Vietnam, winter and summer. Winter generally lasts from November to April with rather pleasant cool weather. The average temperature in this season is about 60°F. This season is usually rather dry. The summer season begins in May and lasts till October. It is a time of tremendous heat, heavy rainfall, and typhoons. The average temperatures range between 86° and 89°F. The daily temperatures may run in the 90's during this season.
South Vietnam
The south has a monsoon climate with rather consistent average temperatures of between 77° and 86°. There are two main seasons—wet and dry. The dry season lasts from November to April with barely a day of rain and then changes to the rainy season which lasts from May to October.
November is usually the month of transition. There is an exception to this in the region of Phan Thiet to Phan Rang where the rains come from September to December. Typhoons are common along the coast between July and November.
The hottest and most unpleasant time in South Vietnam is generally between February and April when the atmosphere is humid and the many storms seldom break into a cooling rain.
In Central Vietnam, the climate is a transition between the climates of the north and south.
HOTTEST MONTHS
| North Vietnam | June, July, and August. |
| South Vietnam | March, April, and May. |
AVERAGE ANNUAL TEMPERATURES
| Saigon | Between 77° and 86°. The lowest temperature ever recorded in Saigon was 57°. Mean maximum temperature is approximately 95° in April. Mean minimum—approximately 70° in January. |
| Dalat | Temperatures here are considerably lower with a 60-70 0 range in winter. The highs and lows for the year are around 80° and 40°. Ideal weather is from November to March, during the dry season. |
| Hue | Between 68° and 86°. |
| Hanoi | Between 63° and 86°. |
Rainfall
Rainfall in Vietnam is heavy. The yearly average is about 59 inches. The maximum annual amount of rain is usually registered at Hue where it often reaches 110 inches. At Hanoi, the rains begin at the end of May and reach their height in August, with 14 inches for that month. The dryest region is Gap Padaran where the yearly amount is only three inches.
Saigon's monthly rainfall average during the rainy season is approximately 50 inches.
WILDLIFE
Flora
As in all tropical countries, Vietnam has a range of plants that vary from those of great beauty to those of danger. It has been reported that more than 2,000 varieties of orchid grow wild in the jungles of Vietnam. Beautiful flowers can be found in gardens year-round in the cooler areas of the country such as Dalat and other mountain areas.
The Botanical Gardens in Saigon has one of the best collections of orchids and equatorial plants in the world.
There are also dangerous plants such as several species of poisonous nettles growing in the southern part of the country. They grow to a height of 10 to 15 feet and have pointed, heart-shaped leaves with serrated edges which contain poisonous hairs. Contact with these plants causes a painful skin eruption.
Another item of special interest is the sack tree (Antiarus Toxicaria) which has a poisonous sap. Natives and Viet-Cong use the sap for arrow poison. The tree grows to a height of 100 feet and its leaves are similar to those of an elm.
Fauna
There are up to 500 species of fauna in Vietnam. Except for urban and built-up areas, the country is one big hunting ground. Indeed, in times of peace, it could be the hunting paradise of Asia.
The favorites of big-game hunters include tigers, panthers, elephants, wild oxen and buffalo, boars, bears, deer, capi-corns, Cambodian roe, koupreys, and others. Small game include birds ranging from the peacock to the partridge.
A popular small animal caught by the use of a snare is the mouse-deer.
There are also many monkeys in the Vietnamese forests, and each year thousands are exported for medical research.
Two of the most outstanding zoo's in the country are located in Saigon and Dalat. The zoo at Dalat is small but impressive. It is located inside a forest reserve and the animals can be observed in their natural habitat.
Snakes
There are more than 60 known species of snakes, 20 of them poisonous. They include cobras, kraits, vipers, and water snakes.
Caimans
Pythons and caimans are hunted for their skins which have great value. Alligators are often a threat to villagers, especially in the south.
Turtles
There are various species of turtles in the country, but the caret, common around islands, is popular because its shell can be used for handicrafts.
Rodents
Rodents are a problem for farmers and housewives. There are great numbers of rats, mice. moles, squirrels, etc., and some rats are as big as house cats.
Fish
In addition to the species described in Chapter 9,