We describe a case of male takeover in the ursine black-and-white colobus (Colobus vellerosus). I... more We describe a case of male takeover in the ursine black-and-white colobus (Colobus vellerosus). In April 2001, an all-male group attacked and eventually invaded our uni-male study group. Aggression increased following the takeover and the former resident male, severely wounded, became peripheral. The youngest immature received severe aggression from the new males but survived. The immature's mother intervened in most instances of this aggression. Eventually, the former resident male re-established relationships with some of the females and concurrently intervened to protect the immature. Defeated males that stay in their group can contribute to the protection of infants born during their tenure from infanticidal males. The females mated with the new males. Takeovers may be a means by which males acquire groups of females in C. vellerosus.
The forest fragments surrounding the Boabeng-Fiema Monkey Sanctuary (BFMS) in central Ghana shelt... more The forest fragments surrounding the Boabeng-Fiema Monkey Sanctuary (BFMS) in central Ghana shelter small populations of Colobus vellerosus. Little is known about these populations or the ability of the fragments to support them, despite the fact that these fragments represent potentially important habitat for the colobus in this region. We compared the diet of three groups of C. vellerosus in the fragments to two groups in BFMS. We also examined the differences in plant species composition and food abundance among fragments. The study took place from June to November 2003. Dietary data were collected using scan sampling. Plant species composition and food abundance were evaluated using tree plots and large tree surveys. As in BFMS groups, leaves constituted the highest proportion of the diet of fragment groups, yet the colobus in fragments fed on more lianas than did those in BFMS. Over 50% of all species observed eaten by colobus in the fragments were not consumed in BFMS groups during the same season. Food abundance was similar between fragments and BFMS, although species composition differed. There was no relationship between the density of colobus and the density of food trees or percentage of food species, suggesting that other factors may be influencing the number of colobus present. This study highlights the broad dietary range of C. vellerosus, which may be a factor allowing its survival in these fragments.
In nonhuman primate groups that utilize crop and food-raiding strategies, the inclusion of human ... more In nonhuman primate groups that utilize crop and food-raiding strategies, the inclusion of human food in the diet can have a pervasive impact on the activity budget. Human food is usually of higher quality and energy per unit than wild food. Thus, metabolic demands may be reached sooner on a human food diet, which in turn leads to improved foraging
Commensalism and conflict: the human–primate interface. American Society of Primatologists, Norman, 2005
The population of Ursine colobus (Colobus vellerosus) is thought to be declining throughout most ... more The population of Ursine colobus (Colobus vellerosus) is thought to be declining throughout most of its range in West Africa. In eastern Côte d'Ivoire and southwestern Ghana, sightings of C. vellerosus in various reserves and National Parks is reported as rare or few today, in contrast to 'common'sightings in the 1970s [Asibey, 1978; Struhsaker & Oates, 1995; McGraw et al., 1997-1998; Fisher et al., 1999-2000; Oates et al., 2000]. In Togo, there have been no published sightings for over 20 years [Asibey, 1978]. In Bénin, only a few small ...
Group size influences foraging efficiency in several primates. We examined the activity budgets o... more Group size influences foraging efficiency in several primates. We examined the activity budgets of 3 groups of Geoffroy's pied colobus (Colobus vellerosus) at the Boabeng-Fiema Monkey Sanctuary in Ghana to determine whether larger group size induces scramble competition. We studied 2 groups (B1; N= 7-8 and WW; N= 31-33) occupying slightly overlapping home ranges from August to November 2000. We observed the third group, B2 (N= 15-16), comprising B1 and 7 male invaders in the same home range as B1 ...
We describe a case of male takeover in the ursine black-and-white colobus (Colobus vellerosus). I... more We describe a case of male takeover in the ursine black-and-white colobus (Colobus vellerosus). In April 2001, an all-male group attacked and eventually invaded our uni-male study group. Aggression increased following the takeover and the former resident male, severely wounded, became peripheral. The youngest immature received severe aggression from the new males but survived. The immature's mother intervened in most instances of this aggression. Eventually, the former resident male re-established relationships with some of the females and concurrently intervened to protect the immature. Defeated males that stay in their group can contribute to the protection of infants born during their tenure from infanticidal males. The females mated with the new males. Takeovers may be a means by which males acquire groups of females in C. vellerosus.
The forest fragments surrounding the Boabeng-Fiema Monkey Sanctuary (BFMS) in central Ghana shelt... more The forest fragments surrounding the Boabeng-Fiema Monkey Sanctuary (BFMS) in central Ghana shelter small populations of Colobus vellerosus. Little is known about these populations or the ability of the fragments to support them, despite the fact that these fragments represent potentially important habitat for the colobus in this region. We compared the diet of three groups of C. vellerosus in the fragments to two groups in BFMS. We also examined the differences in plant species composition and food abundance among fragments. The study took place from June to November 2003. Dietary data were collected using scan sampling. Plant species composition and food abundance were evaluated using tree plots and large tree surveys. As in BFMS groups, leaves constituted the highest proportion of the diet of fragment groups, yet the colobus in fragments fed on more lianas than did those in BFMS. Over 50% of all species observed eaten by colobus in the fragments were not consumed in BFMS groups during the same season. Food abundance was similar between fragments and BFMS, although species composition differed. There was no relationship between the density of colobus and the density of food trees or percentage of food species, suggesting that other factors may be influencing the number of colobus present. This study highlights the broad dietary range of C. vellerosus, which may be a factor allowing its survival in these fragments.
In nonhuman primate groups that utilize crop and food-raiding strategies, the inclusion of human ... more In nonhuman primate groups that utilize crop and food-raiding strategies, the inclusion of human food in the diet can have a pervasive impact on the activity budget. Human food is usually of higher quality and energy per unit than wild food. Thus, metabolic demands may be reached sooner on a human food diet, which in turn leads to improved foraging
Commensalism and conflict: the human–primate interface. American Society of Primatologists, Norman, 2005
The population of Ursine colobus (Colobus vellerosus) is thought to be declining throughout most ... more The population of Ursine colobus (Colobus vellerosus) is thought to be declining throughout most of its range in West Africa. In eastern Côte d'Ivoire and southwestern Ghana, sightings of C. vellerosus in various reserves and National Parks is reported as rare or few today, in contrast to 'common'sightings in the 1970s [Asibey, 1978; Struhsaker & Oates, 1995; McGraw et al., 1997-1998; Fisher et al., 1999-2000; Oates et al., 2000]. In Togo, there have been no published sightings for over 20 years [Asibey, 1978]. In Bénin, only a few small ...
Group size influences foraging efficiency in several primates. We examined the activity budgets o... more Group size influences foraging efficiency in several primates. We examined the activity budgets of 3 groups of Geoffroy's pied colobus (Colobus vellerosus) at the Boabeng-Fiema Monkey Sanctuary in Ghana to determine whether larger group size induces scramble competition. We studied 2 groups (B1; N= 7-8 and WW; N= 31-33) occupying slightly overlapping home ranges from August to November 2000. We observed the third group, B2 (N= 15-16), comprising B1 and 7 male invaders in the same home range as B1 ...
Uploads
Papers by Tania Saj