Behavioral and endocrine dynamics associated with infanticide in a black and white colobus monkey (Colobus guereza)

Infanticide has been observed in several colobines, but only one infanticide has previously been documented for black and white colobus monkeys (Colobus guereza). This report describes an infanticide observed in Kibale National Park, Uganda, in the summer of 2001. An adult male from a neighboring group attacked and killed a young infant whose mother subsequently remained in her own group and was observed mating 10 days later. She engaged in two mating periods of several days each, separated by approximately 1 month, during which she copulated frequently with the dominant male within her group. Urinary estrogen (EC) and progesterone metabolite (PdG) excretion patterns demonstrated that the female resumed ovarian cycling soon after the infanticide. Because the infanticidal male did not attempt to mate with the victim's mother, his actions were not consistent with the predictions of the sexual-selection hypothesis. We speculate that infanticide associated with intergroup aggression may help secure access to high-quality resources for the infanticidal male's group.     

Observed case of maternal infanticide in a wild group of black-fronted titi monkeys (<Emphasis Type="Italic">Callicebus nigrifrons</Emphasis>)

A maternal infanticide was observed in a group of unprovisioned wild black-fronted titi monkeys (Callicebus nigrifrons). An approximately 3-day-old male infant was killed by his mother. A post-mortem revealed the infant to be clinically healthy. We considered various hypotheses to explain why this behavior occurred (e.g., reproductive advantage, stress, nutritional, infant viability and population density). It is noteworthy that the mother and not the father killed the infant, since in this species the father provides considerable infant care from a few hours after birth.     

Experimental study on sexual behavior between mother and son in Japanese monkeys (Macaca fuscata)

A mother, her adult son, four adult males and six adult females from a free-ranging group at Katsuyama were paired in a cage in the sexual seasons from 1976 to 1980. The paired subjects were classified into the following three types: mother and son, familiar pairs and unfamiliar pairs. The familiar pairs consisted of monkeys who had been in the Katsuyama group until about six months before the experiment. The unfamiliar pairs consisted of monkeys who had not met each other at all or who had not met each other for more than eight years before the experiment. Serial mounts which terminated with ejaculation occurred in nine of ten unfamiliar pairs, four of five familiar pairs, but there were none between the son and mother. The son and mother did not appear to be sexually aroused between themselves, although they were sexually active to other partners. However, on rare occasions, the son mounted singly on the mother, and on one occasion he ejaculated. Their interaction did not change essentially during the three years. The son rarely mounted serially on a female who had a close relationship with his mother.     

One observed case of temporary adoption of an infant by unrelated nulliparous females among wild chimpanzees in the Mahale Mountains,Tanzania

A 2.4-year-old male chimpanzee in the Mahale Mountains, Tanzania became separated from his mother probably because of contagion of the flu-like sickness. He was adopted alternately by two unrelated immigrant females for at least six days before he was reunited with his mother. This episode is described and analyzed in relation to the babysitter relationships among female chimpanzees. The adaptive significance of the babysitting behavior of nulliparous females is discussed.     

Identification of a case of Y:18 translocation using a Y-specific repetitive DNA probe

Summary We have used a recombinant DNA clone derived from the Y-specific 3,4-kb repeats for in situ chromosome hybridization and Southern blotting analysis to identify a case of de novo Y;18 translocation. The proband has a chromosome complement of 46,XY and a variant chromosome 18 with a Q-bright and C-positive short arm. The father has a normal male karyotype of 46,XY. The mother has a female karyotype of 46,XX and an unusually large Q-bright satellite on one chromosome 22. In situ hybridization with the 3,4-kb probe to the metaphase preparations of family members indicated that the additional Q-bright material in the proband's variant chromosome 18 derived from the Y chromosome of his father, and not from the variant chromosome 22 of his mother. On Southern hybridization, the proband had approximately twice the amount of 3,4-kb repeats per cell as his father. These observations suggest a de novo genetic rearrangement in the proband which probably occurred during the father's spermatogenesis.     

A case study of mother-son transfer in mountain gorillas

In mountain gorillas (Gorilla g. beringei), male immigration in bi-sexual units is rare. This paper presents the case of a nearly weaned male infant gorilla who followed his mother in her transfer. This case was recorded in the study population at the Kariske Research Center in 1988. The data come from observation in Group B (on 12 days just prior to the transfer and on 54 days after the transfer over a period of 6 months). The situation of the infant did match the conditions in which infanticide occurs in gorillas, but he was not killed, despite receiving male aggression and being wounded twice. In fact, both the mother and the infant received male aggression more frequently than the long term residents in the group. The aggression received by the mother decreased after she mated with the males and after she weaned the infant. The aggression received by the infant, however, did not decrease after his mother mated with the males, and increased in intensity. The infant reacted fearfully to male aggression, in marked contrast to his mother, who reacted either with indifference, or by simply avoiding the males. The aggression eventually stopped, and the infant became a blackback in Group B. Evolutionarily, the death of the infant would not have markedly accelerated the mother's return to estrus, but the death of the infant could still have benefitted the males, by decreasing the reproductive output of a competitor. Adult male gorillas are also presumably selected to resist male immigration. Proximately, the aggression directed towards the infant was not related to mating access to the mother. The sex of the infant may contribute to explain the post-transfer male aggression, but data on the integration of old female infants in a new group is needed to test whether the sex of the infant has an effect on their vulnerability to infanticide. Also, the intense fear displayed by the infant may have played a role in prompting male aggression.     

Male altruism and wing polymorphism in a parasitic wasp

Males ofTrichogramma sp., a gregarious parasitoid which attacks eggs of the yellow-legged tussock mothIvela auripes (Lepidoptera: Lymantriidae), are polymorphic for wings. In mating within host eggs, no difference in mating success was observed between winged (large) males and wingless (small) males, whereas in mating outside eggs, the former were superior to the latter. Some wingless males were observed to perform sneaking copulation on egg masses. In the 1-male brood, which is thought to be founded by 1 mother wasp, the male size tended to decrease as the number of females per brood increased. But in the 2-male brood, which is assumed to be added with 1 more smaller male produced by the second mother wasp in double parasitism, the larger male did not reduce his size, compared with the male of the 1-male brood with an equal number of females. This phenomenon can be explained reasonably by a version of the kin-selection theory: When there is only 1 male in a host egg, he transfers resources in the egg to his sister females, but, when another male appears, he decides to act to the females less altruistically.     

Brief report: Infant-killing and infant disappearance following male takeovers in a group of free-ranging howling monkeys (Alouatta palliata) in Costa Rica

Events surrounding an infant-killing following a male takeover are described for a group of free-ranging howling monkeys in Costa Rica, and additional evidence is presented for infant disappearances following three previous male takeovers. Infant-killing is best interpreted in this context as a male reproductive strategy, as infant-killing did effectively shorten the interbirth interval, and only infants of high-ranking females died or disappeared following a male takeover. Due to the exclusive access of the dominant male to high-ranking estrous females, an incoming male who had lived as a peripheral male before taking over the group would run little risk of eliminating his own offspring in the course of killing the offspring of high-ranking females.     

The role of routine serum testosterone testing: routine hormone analysis is not indicated as an initial screening test in the evaluation of erectile dysfunction

A 60-year-old male physician is self-referred to your office for evaluation of his erectile dysfunction, which has been worsening for 5 years. He reports his erections rarely achieve fullness for penetration, and he is unable to ejaculate. He has tried sildenafil citrate (Viagra(R); Pfizer Inc, New York, NY) with mild success in the past. He has a strong libido and feels healthy. He rarely exercises, but is on his feet most of the day at work. He has been healthy his whole life and never seeks a doctor's attention. He has no other medical problems. His only medication is a baby aspirin once a day. His physical examination, including genitalia, is normal. As part of his initial visit, should his serum testosterone level be checked by his urologist?     

A tiger mouse and relatives. Variants caused by an activated transposable element?

In a laboratory-bred population of wild Peruvian house mice, one male had an excessive rate of non-pairing of the X and Y chromosomes. After crossing him with laboratory stock mice, a mouse of very unusual phenotype appeared from a yellow (AyA) mother. He was yellow with black dorsal stripes; hence Tiger. He was mated to many females, and inbred F2 and F3 generations were raised. There were no more tiger phenotypes, but his F1 contained an excess of black-and-tans over yellows, showing him to be a gonosomic mosaic Ayat/atat; the homozygous cell line probably arose from the heterozygous one. The mitotic karyotype was normal. Some of Tiger's mates were of known allozyme types and their progeny were scored. The allozyme segregations were normal, except at the Es-3 locus (esterase-3), for which Tiger was typed as homozygous. Several unusual events among Tiger's close relatives included a mutation to an unstable pattern mutant, three probable translocations, and several cases of somatic defect. All unusual mice derived from Tiger's yellow mother, whose genome was one-quarter Peruvian. Yellow is associated with an ecotropic murine leukemia virus. The Peru genome is characterized by a high occurrence of mutation and aberrant karyotypes. It is suggested that something from the Peru genome in Tiger's mother caused instability of the DNA sequence associated with yellow, with related disturbance at different locations thereafter. The nature of this instability, and of the Peru genome, is discussed.     

Behavioral development of a malformed infant in a free-ranging group of Japanese monkeys

The behavioral development of a malformed male infant in a free-ranging Japanese monkey group, whose hands were completely missing and whose hind feet were distorted, was investigated during the first one year of life, by comparison with normal infants. In the first few weeks of life, the malformed infant was not able to move by himself and was almost completely dependent on his mother's help. He gradually became able to creep with his forelimb elbows and distorted hind feet at about the first month of life, and was able to walk bipedally on his hind feet, though unstably, after the sixth month of life. His locomotor ability, however, was essentially inferior to that of normal infants throughout the first one year of life. His social interactions with the group members were different from those of normal infants. Normal infants increased their interactions with sameaged infants or older juveniles through active behavior-like play, whereas the malformed infant developed relations particularly with adults through behavior such as passive body contact. The conditions for survival of the observed malformed infant are discussed.     

A variant of the fra(X) syndrome

Summary A decondensed site at band q26 of the X chromosome was found in a male baby with growth and developmental retardation and a dysmorphic syndrome, as well as in his phenotypically normal mother, without using any special culture conditions.     

Do Adult Male Spider Monkeys (Ateles geoffroyi) Preferentially Handle Male Infants?

Infant tolerance by adult males has been observed in many primate species with multimale–multifemale mating systems, but males do not usually initiate interactions with infants. In male philopatric species, such as spider monkeys, adult males within a community exhibit high levels of cooperation and affiliation, and they might therefore be motivated to create bonds with potential future allies. Based on this hypothesis we predicted that adult male spider monkeys would participate in infant handling more than adult females and they would preferentially direct handling toward male infants. Between January 2008 and July 2010, we collected 884?h of observation on a community of wild spider monkeys at Runaway Creek Nature Reserve in Belize. During this period we observed 120 incidences of affiliative interactions between infants and adults other than their mother. The adult initiated the majority of nonmother adult–infant interactions (78?%). All available infants (5 males, 7 females) were handled during the study. All 9 of the community adult males handled infants but only 7 of 14 adult females did so. Adult males handled infants significantly more often than did adult females and males also handled young infants more often than older infants. Significant infant sex differences in handling appeared in infants >6?mo when adult males handled males significantly more than females. The patterns of infant handling among age–sex class dyads reflect the affiliative social patterns that we see in adult spider monkeys. These results provide support for the hypothesis that adult males preferentially handle male infants as a strategy for fostering social bonds.     

Adult male replacement and subsequent infant care by male and siblings in socially monogamous owl monkeys (<Emphasis Type="Italic">Aotus azarai</Emphasis>)

Owl monkeys (Aotus azarai) are small, territorial, socially monogamous primates that show intense infant care by the adult male in the group. It has been hypothesized that male care may be adaptive because it increases offspring survival and/or reduces the metabolic costs to the female of raising the offspring. Alternatively, males may provide care even when they are not related to the infants to increase future reproductive opportunities. We describe changes in infant care patterns that took place after the eviction of the resident male by a solitary male in an owl monkey population in the Argentinean Chaco. The resident male and mother provided all infant care during the first month of life of the infant, until the male was evicted. During the three-day male replacement event, care of the infant was shared among the mother, a four-year-old sister, and a one-year-old brother. The new male began contributing to infant care soon after entering the group, carrying, and interacting socially with the infant in much the same way as any male regularly does. However, despite receiving biparental care from both the original and new resident males, the infant disappeared at the age of four months and was presumed dead. These are the first reports of care by sibling and by non-putative fathers in wild owl monkeys. Given the significant amount of time that new pairs of owl monkeys spend before reproducing, it is possible that male care in owl monkeys functions as mating effort as much as or more than parenting effort.     

A fatal attack on an unweaned infant by a non-resident male in a free-ranging group of Japanese macaques (Macaca fuscata) at Katsuyama

A non-resident male attacked a 4-month-old unweaned infant in a free-ranging group of Japanese macaques (Macaca fuscata) and it died 2 days later from a severe wound. When the infant was alone at the feeding site, the non-resident male rushed at it. The infant ran away as soon as it became aware of the male, but was captured. The male bit the infant on its hand, foot, and arm, while continuously scanning his surroundings. He did not kill the infant immediately and, after the infant escaped, he did not chase or attack it at all. Although the infants right arm was bleeding heavily, it survived until the following day. The infanticide occurred a few weeks before the mating season began, so the victims mother soon resumed estrus and the subsequent inter-birth interval was shortened. The first-, second-, and fourth-ranking adult males had died or disappeared a few months before this infanticide, and there were no other group members near the infant when the infanticidal male appeared. The infanticidal male had not been observed before this incident. Compared to one-male groups, the occurrence of infanticide in multi-male groups of Japanese macaques is extremely infrequent. However, in other reports of infanticide in Japanese macaques as well as in this case, it has been noted that infanticide is likely to occur in the pre- or early-mating season, when there are no resident males to defend the infant against attacks, and when a threatening male is least likely to be the infants father.Electronic Supplementary Material Supplementary material is available for this article at     

Huntington's disease in a Sudanese family from Khartoum

Typical Huntington's disease (HD) was studied in a 40-year-old Sudanese man from Khartoum. He had 51 CAG repeats in the Huntington's gene. It is suspected that his mother and his 16-year-old son (both deceased) were also affected. Up to now, there had only been anecdotal evidence of HD in the Sudanese.     

Life span in captive squirrel monkeys (Saimiri) with pathological and reproductive records

Five squirrel monkeys survived for 8 to 14.5 years in captivity. The male reached at least 16 years of age. He was considered to be quite aged and was sterile at time of death. Senile plaques were found in his brain. The females had experienced between five and eight pregnancies and raised between three and six offspring. At least three of the females were fertile in their last year of life. The main findings at autopsy were renal and cardiovascular changes and two tumors (one of them a squamous cell carcinoma of the floor of the mouth). None of the females, including the at least 18-year-old one, seemed as aged as the male. These data give a clue to the life span of the species.     

Xp22.3; Yq11.2 chromosome translocation and its clinical manifestations

We report clinical and molecular investigations in a boy with karyotype 46,Y,der(X)t(X;Y)(qter-->p22.3::q11.21-->qter) and his mother with karyotype 46,X,der(X)t(X;Y)(qter-->p22.3::q11.21-->qter). Haplo-insufficiency for the Xp22.3-->pter chromosomal region in the boy resulted in postnatal growth retardation, developmental delay, partial ichthyosis and facial dysmorphism, but normal external genitals. His mother has a normal phenotype with normal stature and gonadal function but borderline intelligence. FISH-analysis showed a duplication of the Y-heterochromatin probe in the proband and a deletion of the Y933D4 probe in his mother. Molecular investigations situated the Xp22.3 breakpoint between DXS278 and the KAL gene and the Yq11.21 breakpoint between the DYS391 and DYS390 in the proband and his mother. X-inactivation study was performed by analysis of the polymorphic CAG-repeat in the androgen-receptor gene as described showing a normal random (40% versus 60%) inactivation pattern in the mother. The manifestations in male and female with loss of the Xp22.3-->pter and gain of the Yq11.21-->qter chromosomal region are discussed.     

Sotos syndrome with a balanced reciprocal translocation t(2;12)(q33.3;q15)

A balanced reciprocal translocation, 46,XY, t(2;12), was detected in a male infant who had the characteristic features of Sotos syndrome. His father's karyotype was normal, but his mother and an older brother had the same chromosomal abnormality without a history or clinical features of Sotos syndrome.     

Infanticide in wedge-capped capuchin monkeys, Cebus olivaceus

Three cases of infanticide are reported from a well-studied population of wedge-capped capuchin monkeys, Cebus olivaceus, located in the Venezuelan llanos. For each case, we examined the social context and the consequences to the reproductive success of the infanticidal male. In 1 case, the male probably killed his own son. In 2 cases, the male killed an unrelated animal. In all 3 cases, the female conceived in the following breeding season, but in only 1 case did the infanticidal male possibly enhance his own reproductive success. These data are interpreted in the light of current hypotheses for infanticide.