I already wrote much about survival skills when I spoke about crime, deception, our rhythms, physiology and more. Here I will extend this topic.
Survival and self-preservation are very fundamental instincts in Earth's creatures. Our scientists study this instinct much in humans and animals. Especially interesting is for them the idea of self-sacrifice for the good of the pack.
Humans are certainly capable of self-sacrifice for the good of others. A great example of that is parents and grandparents who take care of children at the expense of their own health and resources. This happens often in daily life and is quite noticeable.
Sometimes self-sacrifice is done in mysterious ways. People come to an idea to make an arrangement with God that they give away their life for saving the health of their beloved one. I suspect that my grandmother did that saving my grandfather from his disease and that my mother did that for me, saving me from my disease. I don't have direct evidence of that but intuitively sense that this might have been the case.
There are many legends and stories of heroes saving their cities or armies from enemies by self-sacrifice.
At times of war, whole countries were inspired by ideas of self-sacrifice for the good of their people and people worked and fought hard to defend their countries.
Animal mothers sometimes are observed to sacrifice themselves to defend their offspring from predators.