04-13-2006 14:01

The semi desert area of northern Kenya is an ideal home for wild animals. There are two species of zebras that live here. The most frequently seen is this one with broader stripes, called the Burchell's zebra. The other one with thinner and denser stripes is called the Grevy's zebra, and is relatively rare.

In the past 25 years, the Grevy's zebra population has been reduced to near extinction. Yet, the Burchell's zebra population has flourished. What has led to such a difference?

The Burchell's zebra community is like a wheel. A male zebra forms the center, and about 6 females form his group of wives, surrounded by their children. Their relationship is very close.

The male has absolute power. His main task is to guard against invaders by keeping watch at all times to see if a lion or hyena is near.

The females can then eat the grass at ease. The more they eat, the stronger they will be and the more babies they can bear.

Once there is any sign of danger, the vigilant male zebra will tell others to run quickly.

As a reward, the females will mate with the leader and bear children for him.

No jealousy is present amongst the wives. They help each other to clean their fur and remove lice.

But the peaceful life is soon disturbed by a young male invader. It threatens the position of the leader, who can't resist the invader alone. The leader allies himself with other leaders to protect his wives.

It's like an informal organization uniting the leaders to resist invaders. Their only duty is to reproduce, and prevent other zebras from interference.

The clever Burchell's zebras discovered the advantage of a gregarious life long ago.

The stable family structure has kept the Burchell's zebra families prosperous. This doesn't mean that threats are minimized. Big carnivorous animals roam everywhere looking for a delicious dinner. They are threatening the Burchell's zebras.

Maybe the great number of gnus confused the predator, because they were lucky to escape today.

Though Grevy's zebras are facing the same threat, they have chosen another type of lifestyle.

Male Grevy's zebras don't have special female groups. They have only their own territories. Though it is approximately 10 square kilometers, it makes a male quite happy. He is worried about not having a fixed group of wives.

They can only try to make themselves look smarter and more handsome in their own territory to lure females into their land. But chances of winning favor are few. Many females will refuse their warm invitation.

The choice of a suitable territory is important for attracting females. It should suit her needs. A nursing female needs large amounts of water to ensure plenty of milk. She needs an area where she can drink freely.

Those who have no young yet can live without water for two or three days. They can go farther to areas with good grass.

The males are worried about choosing their territories. They have to choose between plenty of water and fine grass.

Sometimes two male zebras will fight for a suitable territory.

No matter how carefully they choose, they can at most win only one favor. He is not always as lucky as today. More often, he has to wait patiently.

A male Grevy's zebra is best described as a "lonely boss".

Female Grevy's zebras also face many other difficulties, due to the lack of care by males. They have to protect themselves and their children, acting both as mother and father. Therefore, both the birth rate and survival rate of foals are much lower than Burchell's zebras.

We don't know why these species with similar ecological characteristics have such different societal structures. We only know, in areas where the two species coexist, the gregarious Burchell's zebras are having an easier time of living, while the solitary Grevy's zebras are facing greater difficulties.

We often say "unity is strength". This is proven by Burchell's zebras.

The advantage of living in groups is that they are no longer weak individuals. They have many eyes and many ears to guard against enemies, and confuse them during their attack, to avoid being caught.

Many animals choose to live in groups. Some want to breed more offspring, and to avoid predators.

But some animals do so because of other reasons. What are their reasons?

Because of their extroverted life, bats become the second populous species among mammals. The Vampire bat lives solely off the blood of other animals. But surprisingly, they are quite generous in helping each other. It's not always easy to find blood. But a vampire bat will die in three days if it fails to be fed. However, its brothers and sisters will feed it with the blood in their stomachs to alleviate its hunger.

They help first young ones, then adults with close kinship ties. They will also help adults without ties, on the condition that they had helped others before. They follow the principle of mutual assistance.

This type of close relationship can last for about 14 years. One has enough time to repay others.

The behavior of these animals breaks the "the law of the jungle". Not all animals are selfish. At least, within a community, we see the power of solidarity and mutual assistance.


Editor:Wang Ping