Impact of Broad-Spectrum Lighting on Recall Behaviour in a Pair of Captive Blue-Throated Macaws (Ara glaucogularis)
Many birds, including macaws, are highly visual animals able to detect a wide band of light wavelengths ranging into ultraviolet A, but in captivity, full-spectrum lighting is not universally employed. Where purpose-made bird lighting is used, this is typically made with the provision of ultraviolet B radiation and vitamin D3 synthesis in mind. Limited research […]
Ultraviolet colour perception in European starlings and Japanese quail
Whereas humans have three types of cone photoreceptor, birds have four types of single cones and, unlike humans, are sensitive to ultraviolet light (UV, 320-400 nm). Most birds are thought to have either a violet-sensitive single cone that has some sensitivity to UV wavelengths (for example, many non-passerine species) or a single cone that has […]
Color preferences in gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes)
Color plays an important biological role in the lives of many animals, with some species exhibiting preferences for certain colors over others. This study explored the color preferences of two species of ape, which, like humans, possess trichromatic color vision. Six western lowland gorillas, and six chimpanzees, housed in Belfast Zoological Gardens, were exposed to […]
Behavioural–analytical studies of the role of head movements in depth perception in insects, birds and mammals
In this review, studies of the role of head movements in generating motion parallax which is used in depth perception are examined. The methods used and definitiveness of the results vary with the animal groups studied. In the case of insects, studies which quantify motor outputs have provided clear evidence that motion parallax evoked by […]
The eyes of oilbirds ( Steatornis caripensis ): pushing at the limits of sensitivity
An extreme example of a low light-level lifestyle among flying birds is provided by the oilbird, Steatornis caripensis (Steatornithidae, Caprimulgiformes). Oilbirds breed and roost in caves, often at sufficient depth that no daylight can penetrate, and forage for fruits at night. Using standard microscopy techniques we investigated the retinal structure of oilbird eyes and used […]
Sensory Ecology of Electromagnetic Radiation Perception in Subterranean Mole-Rats
Subterranean living animals must handle orientation in their habitat with limited cues, among which is light scarcity. Zambian mole-rats belong to the rodent genus Fukomys and spend the majority of their lifetime underground in extensive burrow systems. These mole-rats have generally been considered as functionally blind, but recent morphological findings have suggested that their visual […]
The evolution of binocular vision
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The role of color in high-level vision
Traditional theories of object recognition have emphasized the role of shape information in high-level vision. However, the accumulating behavioral, neuroimaging and neuropsychological evidence indicates that the surface color of an object affects its recognition. In this article, we discuss the research that examines the conditions under which color influences the operations of high-level vision and […]
Facultative control of avian unihemispheric sleep under the risk of predation
Birds and aquatic mammals are the only taxonomic groups known to exhibit unihemispheric slow-wave sleep (USWS). In aquatic mammals, USWS permits sleep and breathing to occur concurrently in water. However, the function of avian USWS has been unclear. Our study is based on the premise that avian USWS serves a predator detection function, since the […]
Initial findings on visual acuity thresholds in an African elephant (Loxodonta africana)
Abstract 10.1002/zoo.20259.abs There are only a few published examinations of elephant visual acuity. All involved Asian elephants (Elephas maximus) and found visual acuity to be between 8′ and 11′ of arc for a stimulus near the tip of the trunk, equivalent to a 0.50 cm gap, at a distance of about 2 m from the eyes. We […]