When animals gather, specific collective nouns often describe the group, reflecting a long history of observation. These terms offer a more distinct identification for a species’ social arrangement than the simple word “group.” Kangaroos, the iconic Australian marsupials, are no exception to this tradition of unique naming conventions for their assemblies.
The Specific Collective Names
The most common term for a group of kangaroos, particularly in Australia, is a “mob.” This term, used since at least 1846, is the only collective noun for kangaroos included in the Australian National Dictionary. It implies a gathering or movement of the animals across their grazing lands.
While “mob” is prevalent, a group of kangaroos may also be referred to as a “troop” or a “court.” The term “troop” suggests a more organized or moving formation, while “court” is a less frequent and more formal collective noun.
Social Structure and Group Behavior
Kangaroos gather in mobs because the structure offers advantages for survival and social cohesion. Grouping provides increased vigilance, meaning more eyes and ears are available to detect predators like dingoes. This cooperative alertness is a primary function of the mob, enhancing the defense and providing collective security for all members.
The social hierarchy within the mob is maintained by a dominant male, often called a “boomer” or an “old man.” This individual asserts his status through displays, including ritualized fighting or “boxing,” which establishes mating rights and helps maintain order. Non-aggressive behaviors, such as nose-touching and sniffing, also reinforce social bonds among members.
Grouping also facilitates efficiency in foraging, as a larger number of individuals can locate and graze on suitable pastures more effectively. The mob acts as a setting for social learning, allowing younger members to acquire necessary survival skills from older kangaroos. This structure ensures stability and the successful transmission of knowledge across generations.
Composition and Size of the Group
The makeup of a kangaroo mob is fluid, as individuals often join and leave the group, making it a non-territorial and constantly changing assembly. Size varies depending on the species and environmental factors, such as the availability of food and water. While small groups may contain five to ten individuals, large aggregations can number over fifty or even a hundred kangaroos when conditions are favorable.
The composition of a mob centers around several adult females, known as does or jills, and their young, called joeys. These females often form stronger bonds and may stay within their natal group for life, creating a foundation for stability. One or two mature males are generally present, with the largest dominating breeding opportunities and defending the group. Large gatherings are most common in areas with abundant resources, where the benefit of mass feeding outweighs the costs of close proximity.