The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
David P. Watts - One of the best experts on this subject based on the ideXlab platform.
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Infanticide in mountain gorillas new cases and a reconsideration of the evidence
Ethology, 2010Co-Authors: David P. WattsAbstract:Data on six cases of Infanticide, one Infanticide attempt, and one suspected Infanticide in mountain gorillas (Gorilla gorilla beringei) are presented here for the first time. These and previously reported cases in the same population are analyzed in order to assess the circumstances and consequences of Infanticide. Most Infanticides occur when infants' mothers are not accompanied by their group's mature male (usually because he has died). Infants in this situation are almost certain to be killed by unfamiliar males unless they are nearly weaned. Active defense of infants by females is ineffective, and females cannot avoid unfamiliar males for prolonged periods. In contrast, Infanticide is rare — yet has been observed — in encounters between mature males. It is not associated with group takeovers and male eviction by extra-group males, unlike the case in many other mammals. Demographic constraints and reproductive competition limit the occurrence of defensive coalitions between males. These factors, plus the high risks associated with male/male aggression, inhibit the occurrence of group takeovers by male coalitions. Infanticide shortens interbirth intervals and results in a high probability that a female will mate with the infanticidal male. These findings support the sexual-selection hypothesis for the evolution of Infanticide and strongly support the argument that intersexual mutualism and intraspecific aggression have been central factors in gorillas' social evolution.
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New cases of inter-community Infanticide by Male Chimpanzees at Ngogo, Kibale National Park, Uganda
Primates, 2002Co-Authors: David P. Watts, Hogan M. Sherrow, John C. MitaniAbstract:Infanticide by males has been recorded in four chimpanzee populations, including that in Kibale National Park, Uganda. Some infanticidal attacks occur during inter-community aggression. The sexual selection hypothesis does not easily explain these attacks because they may not directly increase male mating opportunities. However, females in the attackers’ community may benefit by expanding their foraging ranges and thereby improving their reproductive success; thus Infanticide may increase male reproductive success indirectly. We report two new cases of Infanticide by male chimpanzees at Ngogo, Kibale National Park. Like two previous cases, these occurred during a boundary patrol and were almost certainly between-community Infanticides. The patrolling males attacked despite the proximity of males from the victims’ presumed community. This probably explains why, unlike the earlier cases, they did not completely cannibalize their victims. Such attacks seem to be relatively common at Ngogo and Infanticide may be an important source of infant mortality in neighboring communities. Our observations cannot resolve questions about the sexual selection hypothesis. However, they are consistent with the range expansion hypothesis: the Infanticides occurred during a period of frequent encounters between communities associated with a mast fruiting event, and Ngogo community members greatly increased their use of areas near the attack site during another mast fruiting event one year later. Our observations contribute to growing evidence that lethal intergroup aggression is a common characteristic of wild chimpanzee populations.
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Infanticide and cannibalism by male chimpanzees at Ngogo, Kibale National Park, Uganda
Primates, 2000Co-Authors: David P. Watts, John C. MitaniAbstract:Researchers have documented Infanticide by adult males in four wild chimpanzee populations. Males in three of these have killed infants from outside of their own communities, but most Infanticides, including one from Kanyawara, in Kibale National Park, Uganda, took place within communities. Here we report two new cases of Infanticide by male chimpanzees at a second Kibale site, Ngogo, where the recently habituated chimpanzee community is the largest yet known. Both Infanticides happended during boundary patrols, which occur at a high frequency there. Patrolling males attacked solitary females who were unable to defend their infants successfully. The victims were almost certainly not members of the Ngogo community. Males cannibalized both infants and completely consumed their carcasses. These observations show that Infanticide by males is widespread in the Kibale population and that between-community Infanticide also happens there. We discuss our observations in the context of the sexual selection hypothesis and other proposed explanations for Infanticide by male chimpanzees. The observations support the arguments that Infanticide has been an important selective force in chimpanzee social evolution and that females with dependent infants can be at great risk near range boundaries, but why male chimpanzees kill infants is still uncertain.
John C. Mitani - One of the best experts on this subject based on the ideXlab platform.
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New cases of inter-community Infanticide by Male Chimpanzees at Ngogo, Kibale National Park, Uganda
Primates, 2002Co-Authors: David P. Watts, Hogan M. Sherrow, John C. MitaniAbstract:Infanticide by males has been recorded in four chimpanzee populations, including that in Kibale National Park, Uganda. Some infanticidal attacks occur during inter-community aggression. The sexual selection hypothesis does not easily explain these attacks because they may not directly increase male mating opportunities. However, females in the attackers’ community may benefit by expanding their foraging ranges and thereby improving their reproductive success; thus Infanticide may increase male reproductive success indirectly. We report two new cases of Infanticide by male chimpanzees at Ngogo, Kibale National Park. Like two previous cases, these occurred during a boundary patrol and were almost certainly between-community Infanticides. The patrolling males attacked despite the proximity of males from the victims’ presumed community. This probably explains why, unlike the earlier cases, they did not completely cannibalize their victims. Such attacks seem to be relatively common at Ngogo and Infanticide may be an important source of infant mortality in neighboring communities. Our observations cannot resolve questions about the sexual selection hypothesis. However, they are consistent with the range expansion hypothesis: the Infanticides occurred during a period of frequent encounters between communities associated with a mast fruiting event, and Ngogo community members greatly increased their use of areas near the attack site during another mast fruiting event one year later. Our observations contribute to growing evidence that lethal intergroup aggression is a common characteristic of wild chimpanzee populations.
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Infanticide and cannibalism by male chimpanzees at Ngogo, Kibale National Park, Uganda
Primates, 2000Co-Authors: David P. Watts, John C. MitaniAbstract:Researchers have documented Infanticide by adult males in four wild chimpanzee populations. Males in three of these have killed infants from outside of their own communities, but most Infanticides, including one from Kanyawara, in Kibale National Park, Uganda, took place within communities. Here we report two new cases of Infanticide by male chimpanzees at a second Kibale site, Ngogo, where the recently habituated chimpanzee community is the largest yet known. Both Infanticides happended during boundary patrols, which occur at a high frequency there. Patrolling males attacked solitary females who were unable to defend their infants successfully. The victims were almost certainly not members of the Ngogo community. Males cannibalized both infants and completely consumed their carcasses. These observations show that Infanticide by males is widespread in the Kibale population and that between-community Infanticide also happens there. We discuss our observations in the context of the sexual selection hypothesis and other proposed explanations for Infanticide by male chimpanzees. The observations support the arguments that Infanticide has been an important selective force in chimpanzee social evolution and that females with dependent infants can be at great risk near range boundaries, but why male chimpanzees kill infants is still uncertain.
Gabriel Ramosfernandez - One of the best experts on this subject based on the ideXlab platform.
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intra community Infanticide and forced copulation in spider monkeys a multi site comparison between cocha cashu peru and punta laguna mexico
American Journal of Primatology, 2008Co-Authors: Nicole K Gibson, Laura G Vick, Ana Cristina Palma, Farah Carrasco, David Taub, Gabriel RamosfernandezAbstract:We describe two cases of Infanticide, two suspected Infanticides, and a forced copulation by familiar resident males in two populations of wild spider monkeys (Ateles belzebuth chamek and A. geoffroyi yucatanensis). These are the first known Infanticides and forced copulation in spider monkeys. Data were gathered from four neighboring communities of spider monkeys in Manu National Park at the Cocha Cashu Biological Station, Peru and two communities in the Otoch Ma'ax Yetel Kooh Reserve at Punta Laguna, Mexico, during intensive field studies of over 2,000 hr each. These are rare behaviors, but results suggest that mating history and sexual coercion are important in spider monkey social relationships. Am. J. Primatol. 70:485–489, 2008. © 2007 Wiley-Liss, Inc.
Nobuyuki Kutsukake - One of the best experts on this subject based on the ideXlab platform.
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The evolution of male Infanticide in relation to sexual selection in mammalian carnivores
Evolutionary Ecology, 2018Co-Authors: Tomohiro Harano, Nobuyuki KutsukakeAbstract:The evolution of Infanticide by males has often been explained by the sexual selection hypothesis, which posits that Infanticide improves male reproductive success by shortening the interbirth intervals of the mothers of the killed offspring. In Carnivora, however, the fitness advantages assumed in this hypothesis have been shown in only a few species, and it has been argued that male Infanticide may be nonadaptive in pinniped carnivores. According to the sexual selection hypothesis, male Infanticide is expected to be more prevalent in species in which males are subjected to stronger sexual selection through intrasexual competition over mates. We examined a phylogenetically corrected relationship between male Infanticide and sexual size dimorphism (SSD) as a measure of the intensity of sexual selection in carnivores. Our analyses failed to detect a significant association between the occurrence of male Infanticide and SSD across carnivores, although they showed that, among fissipeds (typically terrestrial carnivores), males in species with stronger male-biased SSD are significantly more likely to commit Infanticide. This suggests that the evolution of male Infanticide is correlated with intense sexual selection in fissipeds. In pinnipeds (Odobenidae, Otariidae, and Phocidae), there was no significant association between male Infanticide and SSD. Assuming that SSD represents the intensity of sexual selection on males, this result is consistent with the argument that Infanticide by male pinnipeds is not a sexually selected behaviour.
Ana Cristina Palma - One of the best experts on this subject based on the ideXlab platform.
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intra community Infanticide and forced copulation in spider monkeys a multi site comparison between cocha cashu peru and punta laguna mexico
American Journal of Primatology, 2008Co-Authors: Nicole K Gibson, Laura G Vick, Ana Cristina Palma, Farah Carrasco, David Taub, Gabriel RamosfernandezAbstract:We describe two cases of Infanticide, two suspected Infanticides, and a forced copulation by familiar resident males in two populations of wild spider monkeys (Ateles belzebuth chamek and A. geoffroyi yucatanensis). These are the first known Infanticides and forced copulation in spider monkeys. Data were gathered from four neighboring communities of spider monkeys in Manu National Park at the Cocha Cashu Biological Station, Peru and two communities in the Otoch Ma'ax Yetel Kooh Reserve at Punta Laguna, Mexico, during intensive field studies of over 2,000 hr each. These are rare behaviors, but results suggest that mating history and sexual coercion are important in spider monkey social relationships. Am. J. Primatol. 70:485–489, 2008. © 2007 Wiley-Liss, Inc.
