关键词: 小型哺乳动物, 自我调节假说, 衰老—母体效应假说

Abstract: Population regulation is one of the most important problems in population ecology. Compared with intrinsic factors , researchers who emphasized on extrinsic factors rarely pay much attention on the variation among individual qualities, so they can't completely explain the potential mechanism for the periodic fluctuations in populations of small mammals. This paper examined the main viewpoints and related experimental evidences of four hypotheses since the birth of self-regulation school. Understanding the low phase is critical in explaining population cycles. At present, senescence-maternal effect hypothesis attracts to most scientists who are devoted to study cycles in populations of small mammals. On contrast, little experimental evidence has been found on polymorphic behavior hypothesis, social biology hypothesis and outbreeding hypothesis, there is much work to be done. The senescence-maternal effect hypothesis is based on stress hypothesis. It proposes that a change in maternal quality occurs in animals present during the peak phase, carries over into the decline and low. There are much older animals in the low phase than other phases duo to a shift in age structure. The older animals can't effectively maintain homeostasis in the face of environmental challenges and may serve to maintain the low phase by affecting survival and reproduction. This hypothesis is considered to be a very hopeful one to account for this problem and is still lacking enough field data. Some problems and directions need to be answered in the future were provided.

Key words: Small mammals, Self-regulation hypothesis, Senescence-maternal effect hypothesis