The reindeer is the symbol of endurance.
As for some men being able to control themselves and others being swept away, that is due to difference of temperament. Some men are sattwic and control comes easy to them, up to a certain point at least; others are more rajasic and find control difficult and often impossible. Some have a strong mind and mental will and others are vital men in whom the vital passions are stronger and more on the surface. Some do not think control necessary and let themselves go. In sadhana the mental or moral control has to be replaced by the spiritual mastery — for that mental control is only partial and it controls but does not liberate; it is only the psychic and spiritual that can do that. That is the main difference in this respect between the ordinary and the spiritual life.