The passage has stated that meerkats exhibit altruism naturally as a group of them stands guard while the others hunt for food, risking their chances of getting any food that day. In fact, the sentinels would not stand there stomch-free. They ensure that they can sustain without food when they undertake the task by eating before it.
Moreover, the guarding meerkats tend to stand near the burrows so that they can escape fast from predators once they attack, of course after alarming the group. The fact that they alarm the others puts the group under the danger of baffling
and losing attention, that time the predator considers them as easy preys.
This noble act of altruism in humans is noticed in donating organs or bloods is not actually free, because the donor may receive approval or attention from the society. Even if he does not, the mere feel of selfworth is considered valuable.
Altruism is a natural behavior noticable in some kinds of animals and humans. Although it may seem noble, it may benefit the giver or the donor which contadicts the core meaning of the word.