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51 Social Groupings
Key Idea: Animals may be solitary, form loosely associated groups, or form complex groups with clear social structures. Each behaviour has its advantages and disadvantages. No animal lives completely alone. At some stage in their lives, all animals must interact with others of their species (e.g. to reproduce or through competitive interactions for food or resources). Generally animals are classed as being solitary, in unstructured social groups, or in structured social groups.
Solitary animal
Solitary animals spend the majority of their lives alone, often in defended territories. They may only seek out others of their species for breeding. Offspring are often driven away shortly after they become independent. Solitary life is often an advantage when resources are scarce or scattered over a large area. Solitary animals include many of the cat family e.g. tiger (above), bears, and various invertebrates. Many animals form loose associations but do not interact socially. Each animal is acting for its own benefit with little or no direct cooperation between them. Schools of fish, flocks of birds, and some herding mammals exhibit this unstructured social grouping. Unstructured social groups provide protection from predators by reducing the possibility of being preyed upon individually. There may also be benefits during feeding and moving. Some species form complex social structures, often based around a family group. Some involve dominance hierarchies in which individuals in the group are ranked socially. Dominance hierarchies help distribute resources and maintain social structure. In some species (e.g. ants and bees), group members are divided into castes with specific roles. Some produce offspring or help raise young, others may be workers or help with defending the colony.
Advantages of large social groupings
1. Protection from adverse physical factors and predators. 2. Assembly for mate selection. 3. Locating and obtaining food. 4. Defence of resources against other groups. 5. Division of labour amongst specialists. 6. Richer learning environment. 7. Population regulation (e.g. breeding restricted to a dominant pair).
Possible disadvantages of large social groupings
1. Increased competition for resources between group members as group size increases. 2. Increased chance of the spread of diseases and parasites. 3. Interference with reproduction, e.g. infanticide by non-parents or cheating in parental care (as in brood parasites) so that non-parents may unknowingly raise another's offspring.
1. Give one advantage and one disadvantage of solitary living:
2. Explain why group behavior, such as schooling, is more about individual advantage than group advantage:
3. (a) Give two advantages of living in social groups:
(b) Give two disadvantages of living in a social group:
