Table 1 Definitions of sociality and tonal sound characters and respective states
From: Phylogenetic review of tonal sound production in whales in relation to sociality
SOCIALITY-BROAD CONCEPT APPROACH | ||||
|---|---|---|---|---|
CHARACTER/STATES | 0 | 1 | 2 | 3 |
SOCIALITY | Species do not live in groups. Mainly found singly or in pairs. Pairs are primarily mother with their calf. Sometimes groups may form but these are temporal (e.g., breeding, feeding, or migration) and do not show any social structure apart from that of mother and calf | Group living species. In addition to mother and calf associations animals are continuously associating with other conspecific. These associations may be short or long-term. Animals within a group may or not be related. Living singly is extremely rare within this species and it is probably limited to old or outcast animals. | Â | Â |
SOCIAL STRUCTURE | Solitary species with strong social bonds limited to the time the calf is dependent of the mother. Animals may aggregate for breeding, feeding, or migration but associations are limited to the duration of these periods. Groups are not socially structured | Group living species where all group members show weak or fluid associations. Both sexes disperse from natal group. | Group living species. Group members show fluid associations but may have long-term associations with specific group members that are not close relatives e.g, male alliances and coalitions. Both sexes disperse from natal group. | Group living species. Group members are close relatives. Natal philopatry is sex dependent but in some species there is no dispersion. Long-term associations. |
SOCIALITY-MULTI COMPONENT APPROACH | ||||
Group Type | Species described as largely solitary, but that are often found in pairs (mother-calf) | Group living species that are generally found in small groups | Group living species that are generally found in medium to large size schools | Â |
Group Stability/Associations | Short when found in non-socially structured groups. Limited to the time the calf is dependent of the mother. | Species where group stability is short. Animals join and leave the group through the day. Described in literature as fluid societies. | Species with fluid societies but were some conspecific group show relatively long lasting associations e.g., male alliances, female nurseries | Species that live in their natal group for life. Animals are related to group members and dispersal is limited showing long-lasting associations |
Group Composition | Mother and calf | Segregated by age and sex | Mixed (contain both sexes and several ages) | Both segregated and mixed (state only used for the test of association not for optimizations) |
TONAL SOUND COMPLEXITY DISCRETE APPROACH | ||||
Tonal Sound Complexity (2-state) | Mean inflection point is less or equal to 1 | Mean inflection point is more than 1 | Â | Â |
Tonal Sound Complexity (2-state) | Mean inflection point is between 0–1 | Mean inflection point is between 1.1–2 | Mean inflection point is between 2.1–3 | Mean inflection point is more than 3.1 |