Dear @Andras, I was watching the video from the Budapest zoo! It seems that we do not speak here about ethics, but sense of a living being that "help is needed"! Such are the cases presented by @Nageswara! Stronger helping the weaker! Animal instinct is concerned!
For me, these situation of "Mutually-Beneficial Animal Relationships" are very impressive. Look at many examples!
Thanks for your contributions and comments. We know so little on the perception and behavioural mechanisms of animals. These examples may be a bit of information for animal ethologists.