Cooperation can trump competition in monkeys through the formation of alliances. Alliances are coalitions of individuals who cooperate with each other to achieve common goals, such as dominance, access to resources, or protection from predators. In monkeys, alliances can be formed between related individuals, such as siblings or cousins, or between unrelated individuals who share common interests.

Alliances can provide a number of benefits for monkeys. For example, allies can help each other defend their territory from rival groups. Allies can also help each other find food and other resources. And allies can provide each other with social support, such as grooming and vocal communication.

The strength of an alliance depends on a number of factors, including the number of individuals in the alliance, the strength of the individuals' bonds with each other, and the degree to which the individuals are able to cooperate with each other. Alliances that are strong can be very effective at achieving their goals. For example, a study of rhesus macaques in India found that alliances were able to successfully defend their territory from attacks by rival groups in 80% of cases.

Alliances are not always successful, however. If the individuals in an alliance are not able to cooperate with each other effectively, the alliance may be unable to achieve its goals. For example, a study of Japanese macaques in Japan found that alliances were unable to successfully defend their territory from attacks by rival groups in 20% of cases.

Overall, alliances can be a very effective way for monkeys to cooperate with each other and achieve common goals. However, the strength of an alliance depends on a number of factors, and alliances are not always successful.