Answer:
the Tigers cooperating more within the group when competing against other groups
Cooperation increases within groups when they perceive an external threat.
Step-by-step explanation:
In social psychology and more specific in group psychology, the more a group feels grounded and have more group identity, structure, clear roles and goals, the more cooperation within the group will increase.
If there is a threat that may affect said group, all the members of the group will play the part in order to mitigate the possible danger.
In this particular case, The tiger is becoming an established groupg and the more they participate against other groups the more group identity the will get, group structure and clear roles and goals, thus allowing cooperation to arise.