Solitary animals such as the
jaguar do not associate except for
courtship and
mating. If an animal taxon shows a degree of sociality beyond courtship and mating, but lacks any of the characteristics of eusociality, it is said to be
presocial. Although presocial species are much more common than eusocial species, eusocial species have disproportionately large populations. The
entomologist Charles D. Michener published a classification system for presociality in 1969, building on the earlier work of
Suzanne Batra (who coined the words
eusocial and
quasisocial in 1966). Michener used these terms in his study of bees, but also saw a need for additional classifications:
subsocial,
communal, and
semisocial. In his use of these words, he did not generalize beyond
insects.
E. O. Wilson later refined Batra's definition of
quasisocial.
Subsociality Subsociality is common in the animal kingdom. In subsocial
taxa, parents care for their young for some length of time. Even if the period of care is very short, the animal is still described as subsocial. If adult animals associate with other adults, they are not called subsocial, but are ranked in some other classification according to their social behaviours. If occasionally associating or nesting with other adults is a taxon's most social behaviour, then members of those populations are said to be
solitary but social. See Wilson (1971) and Costa (2006) give readable overviews. Subsociality is widely distributed among the winged insects, and has evolved independently many times. Insect groups that contain at least some subsocial species are shown in
bold italics on a
phylogenetic tree of the
Neoptera (note that many non-subsocial groups are omitted): }}
Solitary but social is a
nocturnal, solitary-but-social
lemur native to
Madagascar. Solitary-but-social animals forage separately, but some individuals sleep in the same location or share nests. The
home ranges of females usually overlap, whereas those of males do not. Males usually do not associate with other males, and male offspring are usually evicted upon maturity. However, this is opposite among
cassowaries, for example. Among
primates, this form of social organization is most common among the nocturnal
strepsirrhine species and
tarsiers. Solitary-but-social species include
mouse lemurs,
lorises, and
orangutans. Some individual
cetaceans adopt a solitary but social behavior, that is, they live apart from their own species but interact with humans. This behavior has been observed in species including
bottlenose dolphin,
common dolphin,
striped dolphin,
beluga,
Risso's dolphin, and
orca. Notable individuals include
Pelorus Jack (1888–1912),
Tião (1994–1995), and
Fungie (1983–2020). At least 32 solitary-sociable dolphins were recorded between 2008 and 2019.
Parasociality Sociobiologists place communal, quasisocial, and semisocial animals into a meta-class: the
parasocial. The two commonalities of parasocial taxa are the exhibition of parental investment, and socialization in a single,
cooperative dwelling. as well as in some other
invertebrates.) A semisocial population has the features of communal and quasisocial populations, but they also have a biological caste system that delegates labor according to whether or not an individual is able to reproduce. Beyond parasociality is eusociality. Eusocial insect societies have all the characteristics of a semisocial one, except overlapping generations of adults cohabit and share in the care of young. This means that more than one adult generation is alive at the same time, and that the older generations also care for the newest offspring. == Eusociality ==