Müller A E, Thalmann U
Anthropological Institute and Museum, University of Zürich, Switzerland.
Biol Rev Camb Philos Soc. 2000 Aug;75(3):405-35. doi: 10.1017/s0006323100005533.
The evolution and origin of primate social organisation has attracted the attention of many researchers, and a solitary pattern, believed to be present in most nocturnal prosimians, has been generally considered as the most primitive system. Nocturnal prosimians are in fact mostly seen alone during their nightly activities and therefore termed 'solitary foragers', but that does not mean that they are not social. Moreover, designating their social organisation as 'solitary', implies that their way of life is uniform in all species. It has, however, emerged over the last decades that all of them exhibit not only some kind of social network but also that those networks differ among species. There is a need to classify these social networks in the same manner as with group-living (gregarious) animals if we wish to link up the different forms of primate social organisation with ecological, morphological or phylogenetic variables. In this review, we establish a basic classification based on spatial relations and sociality in order to describe and cope properly with the social organisation patterns of the different species of nocturnal prosimians and other mammals that do not forage in cohesive groups. In attempting to trace the ancestral pattern of primate social organisation, the Malagasy mouse and dwarf lemurs and the Afro-Asian bushbabies and lorises are of special interest because they are thought to approach the ancestral conditions most closely. These species have generally been believed to exhibit a dispersed harem system as their pattern of social organisation ('dispersed' means that individuals forage solitarily but exhibit a social network). Therefore, the ancestral pattern of primate social organisation was inferred to be a dispersed harem. In fact, new field data on cheirogaleids combined with a review of patterns of social organisation in strepsirhines (lemurs, bushbabies and lorises) revealed that they exhibit either dispersed multi-male systems or dispersed monogamy rather than a dispersed harem system. Therefore, the concept of a dispersed harem system as the ancestral condition of primate social organisation can no longer be supported. In combination with data on social organisation patterns in 'primitive' placentals and marsupials, and in monotremes, it is in fact most probable that promiscuity is the ancestral pattern for mammalian social organisation. Subsequently, a dispersed multi-male system derived from promiscuity should be regarded as the ancestral condition for primates. We further suggest that the gregarious patterns of social organisation in Aotus and Avahi, and the dispersed form in Tarsius evolved from the gregarious patterns of diurnal primates rather than from the dispersed nocturnal type. It is consequently proposed that, in addition to Aotus and Tarsius, Avahi is also secondarily nocturnal.
灵长类社会组织的演化与起源吸引了众多研究者的关注，一种被认为存在于大多数夜行性原猴亚目的独居模式，通常被视为最原始的系统。夜行性原猴亚目在夜间活动时大多独自行动，因此被称为“独居觅食者”，但这并不意味着它们没有社会性。此外，将它们的社会组织称为“独居”，意味着它们所有物种的生活方式都是一致的。然而，在过去几十年中发现，它们不仅都展现出某种社交网络，而且这些网络在不同物种之间存在差异。如果我们希望将灵长类社会组织的不同形式与生态、形态或系统发育变量联系起来，就需要像对群居动物那样对这些社交网络进行分类。在这篇综述中，我们基于空间关系和社会性建立了一个基本分类，以便描述和妥善处理不同夜行性原猴亚目物种以及其他不以紧密群体形式觅食的哺乳动物的社会组织模式。在试图追溯灵长类社会组织的祖先模式时，马达加斯加鼠狐猴和倭狐猴以及亚非丛猴和懒猴特别值得关注，因为它们被认为最接近祖先的状态。这些物种通常被认为呈现出一种分散的一雄多雌制作为其社会组织模式（“分散”意味着个体独自觅食但展现出社交网络）。因此，灵长类社会组织的祖先模式被推断为分散的一雄多雌制。事实上，关于鼠狐猴科的新野外数据以及对原猴亚目（狐猴、丛猴和懒猴）社会组织模式的综述表明，它们呈现出要么是分散的多雄制系统，要么是分散的一夫一妻制，而不是分散的一雄多雌制系统。因此，分散的一雄多雌制系统作为灵长类社会组织祖先状态的概念不再能得到支持。结合“原始”胎盘类动物、有袋类动物以及单孔类动物的社会组织模式数据，实际上最有可能的是滥交是哺乳动物社会组织的祖先模式。随后，从滥交衍生出的分散多雄制系统应被视为灵长类的祖先状态。我们进一步认为，夜猴属和毛耳夜猴的群居社会组织模式以及跗猴的分散模式是从昼行性灵长类的群居模式演化而来，而不是从夜行性的分散模式演化而来。因此，除了夜猴属和跗猴外，还提出毛耳夜猴也是次生夜行性的。
