Morality According to Kohlberg, morality has its root in our ability to accommodate the varying positions of others around us, or at least to tolerate them. We call this empathy. In his more advanced stages of moral development, he asserts that reason and prediction play greater roles in shaping our behaviours. Oddly, morality tends to want to beget a regression to the mean, or conformity, to values, standards, and acts permissible in a culture. People in a culture tend to desire to behave in a narrow range of permissible behaviours. It helps with belonging and acceptance, which those researching interest-based models of social interaction would say is an important element in well-being.
Lack of foresight, impulsivity, and ego-centric reasoning, which Larry Kohlberg would say is the purview of those stuck in the bottom two levels of moral reasoning, they comprising his First Stage.
As is the case with most behaviours, moral reasoning is learned and adopted for its perceived values. For those with arrested development, or brain damage of a defined/undefined type, moral reasoning has little meaning. It might be still interest-based though, and adopted because the alternatives in many contexts are not going to serve the person well. Very intelligent, but otherwise amoral, people can still function well in society because it's the easiest path for them. It's not to say they won't be more opportunistic than others whose conscience plays a larger role in shaping their overt acts.
It's interesting that almost every person will, if comfortable, admit to fantasizing about immoral acts they wouldn't dream of carrying out if others were ever to find out or to observe them. We have to ask ourselves why such behavior is at odds with otherwise lawful and ethical people, and what drives them to value these contrarian acts for sexual or non-sexual reasons.
I don't know that 'the beasts' are capable of moral reasoning...I would think not...but they have instinctual tendencies to act in ways that seem altruistic. I think of dogs defending a toddler from danger, or apparently empathetic toward a crying person, as is commonly seen.