|
|
Ale, S., & Brown, J. (2007). The contingencies of group size and vigilance (Vol. 9).
Abstract: Background: Predation risk declines non-linearly with one's own vigilance and the vigilance of others in the group (the 'many-eyes' effect). Furthermore, as group size increases, the individual's risk of predation may decline through dilution with more potential victims, but may increase if larger groups attract more predators. These are known, respectively, as the dilution effect and the attraction effect.
Assumptions: Feeding animals use vigilance to trade-off food and safety. Net feeding rate declines linearly with vigilance.
Question: How do the many-eyes, dilution, and attraction effects interact to influence the relationship between group size and vigilance behaviour?
Mathematical methods: We use game theory and the fitness-generating function to determine the ESS level of vigilance of an individual within a group.
Predictions: Vigilance decreases with group size as a consequence of the many-eyes and dilution effects but increases with group size as a consequence of the attraction effect, when they act independent of each other. Their synergetic effects on vigilance depend upon the relative strengths of each and their interactions. Regardless, the influence of other factors on vigilance – such as encounter rate with predators, predator lethality, marginal value of energy, and value of vigilance – decline with group size.
|
|
|
|
Anonymous. (2004, 28 February). Nepali newspaper article reporting on snow leopard study., 1.
|
|
|
|
Barnett, K. C., & Lewis, J. C. M. (2002). Multiple ocular colobomas in the snow leopard (Uncia uncia) (Vol. 5).
Abstract: Two singleton female snow leopard cubs are reported with bilateral central upper lid colobomas. In addition, one cub had a coloboma of the fundus in one eye extending from the lower optic disc region. Surgical treatment by wedge resection was successful in both cases. Details of ocular colobomas in the other snow leopards reported in the literature are described and it is suggested that the exact etiology of the condition in this species may be discovered by further study of similar colobomas in the domestic cat.
|
|
|
|
Martin, C. L., Stiles, J., & Willis, M. (1997). Feline colobomatous syndrome. Veterinary-and-Comparative-Ophthalmology, 7(1), 39–43.
Abstract: A syndrome of multiple congenital ocular anomalies in a litter of domestic kittens is described which appears identical to the multiple colobomatous syndrome described in captive Snow Leopards. The lesions varied between kittens in the litter, but ranged from microphthalmos with blindness to mild alterations in the lateral lid margins that resulted in trichiasis. The syndrome of eyelid agenesis in the domestic cat may encompass a broad range of congenital ocular lesions and multiple siblings, but the cause and mechanism of lesion formation is unknown.
|
|
|
|
Schaffer, E., Wiesner, H., & Von Hegel, G. (1988). Multiple ocular coloboma (MOC) with persistent pupillary membrane in the snow leopard (Panthera uncia). Tierarztl Prax, 16(1), 87–91.
Abstract: In a litter of three snow leopards, bilateral colobomata of the upper temporal eyelids, bilateral persistent pupillary membranes and a unilateral coloboma of the optic nerve entrance are described as “Multiple Ocular Colobomata” (MOC). The causal pathogenesis of each of the colobomata is discussed comparatively. The colobomata of the eyelids, essential feature of the MOC syndrome in snow leopards, are most probably not of hereditary, but rather of intrauterine infectious viral origin.
|
|
|
|
Wahlberg, C., Tarkkanen, A., & Blomqvist, L. (1982). Further observations on the multiple ocular coloboma (MOC) in the snow leopard, Panthers uncia. In L. Blomqvist (Ed.), International Pedigree Book of Snow Leopards (Vol. 3, pp. 139–144). Helsinki: Helsinki Zoo.
Abstract: The first observation of the occurrence of multiple ocular coloboma (MOC) in a snow leopard was reported in the International Pedigree Book of Snow Leopards Volume I in 1978 (1). The lesions in this syndrome consist of coloboma of the upper eye lid and uveal coloboma of the globe. Even colobomatous retinal cysts and retinal dysplasia have been noted. The ethiology of in all ten cases of MOC in the snow leopards kept at the Helsinki Zoo were described and discussed in detail in Volume II of the International Pedigree Book of Snow Leopards (2,3). Three cases of MOC in the snow leopards kept at Henry Doorly Zoo, Omaha, Ne., have been described by Phillips (4), one case is known of in Amsterdam (van Bree, personal communication), and two cases in Zoo Zurich (Isenbugel and Weilenmann, pers. comm.) The ethiology of the defect is still not known although various theories ranging from genetic to exogenous factors have been presented.
|
|
