M Kay Izard
Biographic Data
| ID | 5204476 |
|---|---|
| NAME | M Kay Izard |
| GIVEN NAMES | M Kay |
| FAMILY NAME | Izard |
| SIGNATURE | IZARD M K |
| VERIFIED | No |
| TOTAL WORKS | 15 |
| TOTAL CITATIONS | 15 |
| AUTHOR COUNT | 14 |
| EDITOR COUNT | 1 |
| FIRST PUBLICATION YEAR | 1985 |
| LATEST PUBLICATION YEAR | 2006 |
| H-INDEX | 2 |
Twinning and heteropaternity in chimpanzees ( Pan troglodytes )
Unlike monozygotic (MZ) twins, dizygotic (DZ) twins develop from separate ova. The resulting twins can have different sires if the fertilizing sperm comes from different males. Routine paternity testing of a pair of same‐sexed chimpanzee twins born to a female housed with two males indicated that the twins were sired by two different males. DNA typing of 22 short‐tandem repeat (STR) loci demonstrated that these twins were not MZ twins but heterop…
Maternal age, parity, and reproductive outcome in captive chimpanzees (Pan troglodytes)
As early as the 1970s, it was suggested that nonhuman primates may serve as models of human reproductive senescence. In the present study, the reproductive outcomes of 1,255 pregnancies in captive chimpanzees (Pan troglodytes) were examined in relation to parity and its covariate, maternal age. The results show that the percentage of positive pregnancy outcomes was negatively correlated with increasing parity. In addition, spontaneous abortions, …
Examining the terminal investment hypothesis in humans and chimpanzees
The terminal investment hypothesis (Williams [1966] Adaptation and Natural Selection; Princeton, NJ: Princeton University Press) holds that reproductive effort should increase over time in iteroparous species in which reproductive value declines with age. Attempts to model this hypothesis and test it in various species have produced mixed results. Clutton-Brock ([ 1984] Am. Nat. 123:212-229) argued that simply testing for changes in propagule siz…
Creatures of the Dark
Reproduction in Coquerel's dwarf lemur ( Mirza coquereli )
Most nocturnal Malagasy primates, as well as many diurnal species, are highly endangered in their natural habitat. Captive breeding programs have been established for many species, but detailed information on reproduction is only available for three nocturnal taxa: the mouse lemur ( Microcebus murinus ), the dwarf lemur ( Cheirogaleus medius ), and the greater dwarf lemur ( Cheirogaleus major ). In this study, we present data for another nocturna…
Application of fecal steroid techniques to the reproductive endocrinology of female verreaux's Sifaka ( Propithecus verreauxi )
Solid phase extraction, high performance liquid chromatography, and radioimmunoassay were used to test the validity of fecal steroid analysis for assessing ovarian function in sifaka ( Propithecus verreauxi ). Daily fecal samples were collected over a 4 month period from two cycling female sifaka, and single samples were collected from females during normal gestation and males while housed at the Duke University Primate Center. Tests of radioimmu…
Lactation and care for unrelated infants in forest‐living ringtailed Lemurs
An adult female ringtailed lemur ( Lemur catta ) known not to have been pregnant showed spontaneous lactation in response to twin infants born to an unrelated female. The females had met only 7 months earlier, when they and two other unrelated adult females were released from separate locations in a forest enclosure to form a new social group. Three months after release, an adult male from an adjacent enclosure gained access to the new group for …
Reproduction in the slow loris ( Nycticebus coucang )
The reproductive biology of the slow loris (Nycticebus coucang) is poorly documented because of infrequent captive breeding success and the absence of field studies of this species. Reproductive data were collected from a breeding colony of slow lorises held at the Duke University Primate Center for the past 10 years. Nineteen infants were born, with a sex ratio of 1:1 and a neonatal mortality rate of 15.8%. In all cases, litter size was one. Fem…
Scaling of growth and life history traits relative to body size, brain size, and metabolic rate in Lorises and Galagos (Lorisidae, primates)
A broad range of variation in body size, brain size, and metabolic rate occurs within the primate family Lorisidae, thus providing an opportunity to examine the relationship of these three parameters to variation in growth and life history traits. Data on adult body weight, gestation length, lactation length, age at first estrus, litter size, and growth parameters were collected from a captive colony of four lorisid species, Loris tardigradus, Ny…
Description of ultrasonic vocalizations of the mouse lemur ( Microcebus murinus ) and the fat‐tailed dwarf lemur ( Cheirogaleus medius )
Ultrasonic (>20 kHz) vocalizations were recorded from two species of prosimian primates, Microcebus murinus and Cheirogaleus medius . Three types of ultrasonic calls were emitted by isolated or paired M. murinus : 1) “chirps,” short‐duration (30 msec) calls with a sharp onset at 40 kHz followed by rapid and steep declines in frequency and intensity; 2) “twitters,” characterized by a brief pulse at 25 kHz prior to the onset of repeating, frequency…
Lactation length in three species of Galago
Milk expression was used to determine lactation length in three species of Galago at the Duke University Primate Center. Lactation length in G. senegalensis moholi was significantly shorter than the lactation length of either G. garnettii or G. crassicaudatus , but lactation length did not differ between G. garnettii or G. crassicaudatus . Litter size had no significant effect on lactation length. The lactation lengths determined in this study ar…
Reproductive cycles in Tarsius bancanus
The reproductive condition of three pairs of Bornean tarsiers ( Tarsius bancanus ) was documented for 16 months. Each pair was housed separately under a constant photoperiod (L:D = 11.5:12.5) similar to that in their native habitat. Reproductive cycles of females were monitored visually for 6 months and were then monitored with vaginal smears and measurements of external genitalia for an additional 10 months. Progressive proliferation and cornifi…
Isolation of females prior to parturition reduces neonatal mortality in Galago
Eighteen years of birth records for three species of Galago at the Duke University Primate Center were examined to determine the effects of isolation of pregnant females on neonatal mortality rates. Isolation significantly decreased neonatal mortality rates in all three species over neonatal mortality rates in infants born to unisolated females. The frequency of cannibalism of infants did not differ between isolated and unisolated females. Second…
Reproduction in the slender loris ( Loris tardigradus malabaricus )
A breeding colony of slender lorises ( Loris tardigradus malabaricus ) was studied to obtain data for comparison with other prosimian species, to contribute reproductive information for improving management of captive lorises, and to resolve some uncertainties in the literature regarding reproduction in the slender loris. At the Duke University Primate Center, a female slender loris reached sexual maturity at approximately ten months of age and c…
Gestation length in Tarsius bancanus
A gestation length of 178 days was determined for Tarsius bancanus based on a vaginal smear containing whole sperm. This value replaces the only previously reported information on gestation length in tarsiers, a rough estimate of approximately 6 months for T. syrichta
Scaling of growth and life history traits relative to body size, brain size, and metabolic rate in Lorises and Galagos (Lorisidae, primates)
A broad range of variation in body size, brain size, and metabolic rate occurs within the primate family Lorisidae, thus providing an opportunity to examine the relationship of these three parameters to variation in growth and life history traits. Data on adult body weight, gestation length, lactation length, age at first estrus, litter size, and growth parameters were collected from a captive colony of four lorisid species, Loris tardigradus, Ny…
Examining the terminal investment hypothesis in humans and chimpanzees
The terminal investment hypothesis (Williams [1966] Adaptation and Natural Selection; Princeton, NJ: Princeton University Press) holds that reproductive effort should increase over time in iteroparous species in which reproductive value declines with age. Attempts to model this hypothesis and test it in various species have produced mixed results. Clutton-Brock ([ 1984] Am. Nat. 123:212-229) argued that simply testing for changes in propagule siz…
Twinning and heteropaternity in chimpanzees ( Pan troglodytes )
Unlike monozygotic (MZ) twins, dizygotic (DZ) twins develop from separate ova. The resulting twins can have different sires if the fertilizing sperm comes from different males. Routine paternity testing of a pair of same‐sexed chimpanzee twins born to a female housed with two males indicated that the twins were sired by two different males. DNA typing of 22 short‐tandem repeat (STR) loci demonstrated that these twins were not MZ twins but heterop…
Reproduction in the slender loris ( Loris tardigradus malabaricus )
A breeding colony of slender lorises ( Loris tardigradus malabaricus ) was studied to obtain data for comparison with other prosimian species, to contribute reproductive information for improving management of captive lorises, and to resolve some uncertainties in the literature regarding reproduction in the slender loris. At the Duke University Primate Center, a female slender loris reached sexual maturity at approximately ten months of age and c…
Gestation length in Tarsius bancanus
A gestation length of 178 days was determined for Tarsius bancanus based on a vaginal smear containing whole sperm. This value replaces the only previously reported information on gestation length in tarsiers, a rough estimate of approximately 6 months for T. syrichta
Reproductive cycles in Tarsius bancanus
The reproductive condition of three pairs of Bornean tarsiers ( Tarsius bancanus ) was documented for 16 months. Each pair was housed separately under a constant photoperiod (L:D = 11.5:12.5) similar to that in their native habitat. Reproductive cycles of females were monitored visually for 6 months and were then monitored with vaginal smears and measurements of external genitalia for an additional 10 months. Progressive proliferation and cornifi…
Isolation of females prior to parturition reduces neonatal mortality in Galago
Eighteen years of birth records for three species of Galago at the Duke University Primate Center were examined to determine the effects of isolation of pregnant females on neonatal mortality rates. Isolation significantly decreased neonatal mortality rates in all three species over neonatal mortality rates in infants born to unisolated females. The frequency of cannibalism of infants did not differ between isolated and unisolated females. Second…
Description of ultrasonic vocalizations of the mouse lemur ( Microcebus murinus ) and the fat‐tailed dwarf lemur ( Cheirogaleus medius )
Ultrasonic (>20 kHz) vocalizations were recorded from two species of prosimian primates, Microcebus murinus and Cheirogaleus medius . Three types of ultrasonic calls were emitted by isolated or paired M. murinus : 1) “chirps,” short‐duration (30 msec) calls with a sharp onset at 40 kHz followed by rapid and steep declines in frequency and intensity; 2) “twitters,” characterized by a brief pulse at 25 kHz prior to the onset of repeating, frequency…
Lactation length in three species of Galago
Milk expression was used to determine lactation length in three species of Galago at the Duke University Primate Center. Lactation length in G. senegalensis moholi was significantly shorter than the lactation length of either G. garnettii or G. crassicaudatus , but lactation length did not differ between G. garnettii or G. crassicaudatus . Litter size had no significant effect on lactation length. The lactation lengths determined in this study ar…
Reproduction in the slow loris ( Nycticebus coucang )
The reproductive biology of the slow loris (Nycticebus coucang) is poorly documented because of infrequent captive breeding success and the absence of field studies of this species. Reproductive data were collected from a breeding colony of slow lorises held at the Duke University Primate Center for the past 10 years. Nineteen infants were born, with a sex ratio of 1:1 and a neonatal mortality rate of 15.8%. In all cases, litter size was one. Fem…
Scaling of growth and life history traits relative to body size, brain size, and metabolic rate in Lorises and Galagos (Lorisidae, primates)
A broad range of variation in body size, brain size, and metabolic rate occurs within the primate family Lorisidae, thus providing an opportunity to examine the relationship of these three parameters to variation in growth and life history traits. Data on adult body weight, gestation length, lactation length, age at first estrus, litter size, and growth parameters were collected from a captive colony of four lorisid species, Loris tardigradus, Ny…
Lactation and care for unrelated infants in forest‐living ringtailed Lemurs
An adult female ringtailed lemur ( Lemur catta ) known not to have been pregnant showed spontaneous lactation in response to twin infants born to an unrelated female. The females had met only 7 months earlier, when they and two other unrelated adult females were released from separate locations in a forest enclosure to form a new social group. Three months after release, an adult male from an adjacent enclosure gained access to the new group for …
Creatures of the Dark
Reproduction in Coquerel's dwarf lemur ( Mirza coquereli )
Most nocturnal Malagasy primates, as well as many diurnal species, are highly endangered in their natural habitat. Captive breeding programs have been established for many species, but detailed information on reproduction is only available for three nocturnal taxa: the mouse lemur ( Microcebus murinus ), the dwarf lemur ( Cheirogaleus medius ), and the greater dwarf lemur ( Cheirogaleus major ). In this study, we present data for another nocturna…
Application of fecal steroid techniques to the reproductive endocrinology of female verreaux's Sifaka ( Propithecus verreauxi )
Solid phase extraction, high performance liquid chromatography, and radioimmunoassay were used to test the validity of fecal steroid analysis for assessing ovarian function in sifaka ( Propithecus verreauxi ). Daily fecal samples were collected over a 4 month period from two cycling female sifaka, and single samples were collected from females during normal gestation and males while housed at the Duke University Primate Center. Tests of radioimmu…
Maternal age, parity, and reproductive outcome in captive chimpanzees (Pan troglodytes)
As early as the 1970s, it was suggested that nonhuman primates may serve as models of human reproductive senescence. In the present study, the reproductive outcomes of 1,255 pregnancies in captive chimpanzees (Pan troglodytes) were examined in relation to parity and its covariate, maternal age. The results show that the percentage of positive pregnancy outcomes was negatively correlated with increasing parity. In addition, spontaneous abortions, …
Examining the terminal investment hypothesis in humans and chimpanzees
The terminal investment hypothesis (Williams [1966] Adaptation and Natural Selection; Princeton, NJ: Princeton University Press) holds that reproductive effort should increase over time in iteroparous species in which reproductive value declines with age. Attempts to model this hypothesis and test it in various species have produced mixed results. Clutton-Brock ([ 1984] Am. Nat. 123:212-229) argued that simply testing for changes in propagule siz…
Twinning and heteropaternity in chimpanzees ( Pan troglodytes )
Unlike monozygotic (MZ) twins, dizygotic (DZ) twins develop from separate ova. The resulting twins can have different sires if the fertilizing sperm comes from different males. Routine paternity testing of a pair of same‐sexed chimpanzee twins born to a female housed with two males indicated that the twins were sired by two different males. DNA typing of 22 short‐tandem repeat (STR) loci demonstrated that these twins were not MZ twins but heterop…
Biology (14 works) · Primate Behavior and Ecology (11 works) · Ecology (10 works) · Pregnancy (7 works) · Primate (7 works) · Neuroendocrine regulation and behavior (6 works) · Zoology (6 works) · Animal Behavior and Reproduction (5 works) · Demography (5 works) · Reproduction (5 works)