Diurnal haplorhines exhibit derived traits for high-acuity photopic vision, unique across
mammals, and many other vertebrates. Yet, sometime in the mid-Miocene (12–15 MYA), the …

This integrated approach to understanding the evolution of the nocturnal monkey Aotus
combines new information from field research on behavioral ecology with research results …

Primates show activity patterns ranging from nocturnality to diurnality, with a few species
showing activity both during day and night. Among anthropoids (monkeys, apes and …

This paper examines the importance of vision in the lives of nocturnal primates in
comparison to diurnal and cathemeral species. Vision is the major sense in all primates and …

The fovea is a declivity of the retinal surface associated with maximum visual acuity. Foveae
are widespread across vertebrates, but among mammals they are restricted to haplorhine …

Owl monkeys are the only nocturnal primates in the New World and the only nocturnal
anthropoids. They concentrate their activities during the dark phase of the 24-h cycle, with …

Evidence from the early paleontological record of mammalian evolution has often been
interpreted as supporting the idea that mammals were nocturnal for most of their early …

Ethnoprimatological information about owl monkeys is relatively scant compared to other
Neotropical primates. Nocturnality is the characteristic that modulates the interaction …

The subtropical populations of owl monkeys (Aotus) and some lemurs have flexible patterns
that include activity during both day and night. Early studies on the activity patterns of …

Background Do evolutionary specializations lead to evolutionary constraint? This appears
plausible, particularly when specialization leads to loss of complex adaptations. In the owl …