Maybe not sexual, but animals get outcasted/exiled from their groups for all sorts of reasons!

Stolen from AI google response for wolf exile, as an example.

• Aggression: If a wolf displays aggressive behavior towards other pack members, especially the alpha pair or other dominant wolves, it may be exiled to maintain harmony within the pack.

• Injury or illness: Wolves that are injured or sick may be seen as a liability to the pack as they may not be able to keep up with the group or contribute to hunting effectively. In such cases, the pack may exile the weaker individual to ensure the survival of the rest of the group.

• Reproductive competition: In some cases, subordinate wolves may challenge the alpha pair for dominance or breeding rights within the pack. If a wolf is unsuccessful in its attempts to challenge the alpha pair, it may be forced out of the pack.

• Old age: Older wolves that are no longer able to keep up with the pack or contribute to hunting effectively may be pushed out of the group to ensure the pack's survival.

• Genetic diversity: In some cases, wolves may be exiled to prevent inbreeding within the pack. Maintaining genetic diversity is important for the long-term health and survival of the pack.

• Resource scarcity: If resources such as food become scarce, the pack may not be able to support all its members. In such situations, weaker or less dominant wolves may be forced out to reduce competition for resources.

• Behavioral issues: Wolves that consistently display disruptive or antisocial behavior within the pack may be exiled to maintain social cohesion and hierarchy.