Male rats where less likely than female rats to start opening cages.

There is a huge tendency to build up story around a single video, but this is a repeated experiment with far more evidence than shown.

That was my perception as well: the rat immediately tried to mount the rat that had been trapped.

My issue is not with the results of the study, but with interpretation. I think it's possible to explain the desire to free the other rat purely in selfish terms without any nods to altruistic or empathic behavior.

Reproduction is not selfish. It's for species survival.

Reproduction is not for species survival. "Species" is simply an arbitrary label we've assigned as part of the system we use to categorize living things, and doesn't even really match reality very well.

Reproduction is for gene survival. We are simply throw away machines our genes have developed in order to propagate themselves.

No. Everything keeps transforming at each iteration for better serving the system purpose: efficiency (for this system specific set of rules).

The source code (genes) propagation per se would be completely useless to the system, without the processes they express: living systems, the most efficient energy transforming machines the system has been able to incrementally arrange up so far starting out of random stuff.

Therefore reproduction is exactly for that, for allowing the continuation of this energy transforming processes (life processes) in the most efficient way.

The rat doesn't know that...

The rat doesn't (necessarily) know it's selfless to free the other rather. He's acting on instinct. That's the question at hand:are these moral instincts, are they a shared trait with people's.

What the heck does the term moral instincts mean? Are a snake's instincts immoral for driving it to eat the rat?

My real life must be very poor, today I learned another meaning for mount, previously I thought it was a word for installing a controlling sector in a hard disk, to sum up there is hard evidence that I should live more and use computers less, lets say that I should mount life. Context: English is not my native language.

Well, it had just rescued the princess.