By means of this indirect route to genetic survival, the tendency to help genetic relatives, called kin selection, could become an innate characteristic of humans. In fact, kin selection is evident in the behavior of many organisms. For example, just as humans often risk their lives to save close relatives, ground squirrels, capuchin monkeys, and many other mammals and birds emit an alarm to warn nearby relatives of a predator. The alarm helps their relatives but makes the individual who sounds the alarm more vulnerable to attack.
Because kin selection serves the function of genetic survival, preferential helping of genetic relatives should be strongest when the biological stakes are particularly high. This appears to be the case. For example, Gerald Carter and others (2017) conducted experiments with bats and found that the bats shared food with both kin and non-kin under safe conditions. When the conditions seemed more dangerous, however, the bats shared a much greater propor- tion of food with closer relatives.