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Biomedical subjects

C T Snowdon

Publications and source records attributed to C T Snowdon.

At least 37 records · Page 2Linked to original sources
PubMed1990

Nursing does affect the duration of the post-partum to ovulation interval in cotton-top tamarins (Saguinus oedipus).

Reports on callitrichid monkeys have not revealed a significant effect of nursing on interbirth intervals or on post-partum to ovulation intervals. We examined 25 post-partum intervals in cotton-top tamarin females to determine whether nursing infants would affect the length of the post-partum to ovulation interval. Urinary LH/CG and oestrone conjugates were measured in urine samples collected in the 6 weeks after birth. The post-partum to ovulation interval is the number of days between parturition and the rise of urinary LH and oestrone conjugates associated with ovulation. There was an 84% conception rate post partum. Neither mother's parity nor sex of the infants influenced the length of the post-partum to ovulation interval. The post-partum to ovulation interval for females nursing 2 infants was twice as long as for those not nursing or nursing 1 infant (P less than 0.05). The range of post-partum to ovulation interval lengths was more variable in nursing than in non-nursing females (P less than 0.01). Females spent less than 50% of observed time in contact and less than 20% of observed time nursing their infants. Neither the number of tamarins within the family nor the amount of time the mother was in contact with infants correlated with the length of the post-partum to ovulation interval. However, there was a positive correlation between the percentage time that mothers nursed 1 infant at a time and the length of the post-partum to ovulation interval (r = 0.75, P less than 0.02). The underlying mechanisms of suckling-induced delay of ovulation are present in the cotton-top tamarin as in other primate species. However, these nursing effects do not cause the substantial delay in fertility post partum that is associated with non-callitrichid primates.

Animals↗
PubMed1987

The endocrinology of puberty and reproductive functioning in female cotton-top tamarins (Saguinus oedipus) under varying social conditions.

Sexual maturation and fertility were assessed in fourteen cotton-top tamarin (Saguinus oedipus) females under various social conditions. Six tamarin females (20-28 mo of age) showed a suppression of fertility while living with their families. Hormonal profiles demonstrated low, acyclic levels of urinary luteinizing hormone (LH) and estrone-conjugates (E1C). A rapid onset of ovarian and pituitary cyclicity occurred when four of the six females were removed from their families and paired with an unrelated male. In one female, an ovulatory LH peak occurred as early as eight days after pairing and resulted in conception and full-term pregnancy. Two of the six females were housed in total isolation for 30 days following their removal from the family and prior to pairing. Gradual increases in hormone concentrations occurred during isolation; however, there was no ovarian cyclicity until each female was paired with an unrelated male. In all six females, conception occurred before or as a result of the third ovulatory cycle. Partial isolation of a 36-mo-old female resulted in elevated LH and E1C levels, but cyclicity was not observed until the female was paired with an unrelated male. These findings indicate that removal of a female from the family alone does not initiate ovarian cycling. Sexual maturation, or puberty, occurs in female tamarins living with their families between 15 and 17 mo of age when mean LH and E1C levels began to increase. However, when a female is removed and paired at 9 mo of age with an unrelated male, elevated levels of LH and E1C may be seen by 10 and 11 mo of age. Our findings indicate that a suppression of fertility occurs in cotton-top tamarins living with their families, but that reproductive suppression does not affect the process of sexual maturation. Both removal from the family environment and stimulation by an unrelated male tamarin were necessary to induce normal reproductive activity. An acceleration of puberty occurred when a female tamarin was removed from her family early in development and paired with a male.

Animals↗
PubMed1987

Color discrimination by the cotton-top tamarin (Saguinus oedipus oedipus) and its relation to fruit coloration.

Old World monkeys and apes have been reported to differ from New World monkeys in their abilities to discriminate colors across the visible spectrum. Old World monkeys and apes (Macaca, Pan, Pongo) discriminate colors quite accurately, while some New World monkeys studied (Saimiri, Cebus) have shown lower sensitivity to and poorer discrimination of long wavelength light. This study examined the color discrimination ability of another New World primate, the cotton-top tamarin, Saguinus oedipus oedipus (family Callitrichidae). The tamarins were trained to discriminate a set of Munsell color chips, both within the same hue category and from the 2 hue categories on either side of the training hue. Results indicated that the cotton-top tamarin can make accurate discriminations across the visible spectrum. Human subjects were tested under similar conditions in order to compare their color discrimination abilities to those of the tamarins. The tamarins and human subjects had the most difficulty discriminating the same hues. The discrimination abilities of the monkeys were assessed in relation to the coloration of fruits eaten in a natural environment. A list of the species of fruits commonly eaten by various species of New World monkeys was compiled and the coloration of fruits at maturity was noted. It was found that most New World primate species eat fruits whose mature coloration ranges across most of the spectrum.

Adolescent↗
PubMed1986

Technique for hand-rearing and reintroducing rejected cotton-top tamarin infants.

During a one year period, seven rejected cotton-top tamarin infants were hand-reared. A hand-rearing program was developed which included the use of heated surrogates, a non-human primate infant formula, special nipples, and a systematic reintroduction into a family group. This regimen was quite successful. The hand-rearing process yielded a success rate of 75.0%, while the reintroduction process had a success rate of 80.0% for reintroduction into a family group and 100.0% survival rate.

Animal Husbandry↗
PubMed1985

A breeding colony of cotton-top tamarins (Saguinus oedipus).

A breeding colony of cotton-top tamarins is described where 91% of the breeding females are from the first and second laboratory-born generations, and whose infants have a one year survival rate of 62%. Mortality is greatest in the first week of life, and mortality rate is greater for a female's first litter than for subsequent litters. Females without early experience in caring for other infants have a higher infant mortality rate than females with such experience. No seasonal birth patterns have been observed. Large complex cages with food, water and runways located in the upper half of the cage, high protein diets and reduced handling of animals are suggested as additional variables affecting breeding success.

Animal Husbandry↗
PubMed1979

Response of nonhuman animals to speech and to species-specific sounds.

Three questions relate to how nonhuman species respond to speech and species-specific sounds: (1) Do nonhuman species perceive human speech in a human-like fashion? (2) How do nonhuman species perceive their own vocalizatios? and (3) How does human perception of animal sounds differ from the animals' perception of those sounds? Four methodologies are available for studying an animal's perception of sounds: (1) discriminative conditioning; (2) habituation-dishabituation; (3) playbacks in captivity; and (4) playbacks in situ. Each of these techniques has a different degree of ecological validity and has different intrinsic biases toward the conclusions one might draw. Experiments using these methodologies for each of the three questions are reviewed and the methodological problems of each are discussed. A two-stage model of perceiving species-specific sounds is presented which accounts for both categorical perception of sounds and within category discrimination of sounds.

Animal Communication↗
PubMed1976

Failure to show modification of male golden hamster mating behavior through taste/odor aversion learning.

This research investigated whether the dependence of mating behavior in the male hamster on olfactory and gustatory stimuli could be used with the taste/odor conditioning paradigm to alter sexual behavior. Preliminary experiments established the effectiveness of lithium chloride and methyl-atropine nitrate in forming aversions to a saccharin solution. These same agents failed to modify mating behavior when the conditional stimulus was an estrous female hamster. Animals made ill after an exposure to a cotton swab containing phenylacetic acid later showed increased latencies in the initiation of mating with an estrous female swabbed with phenylacetic acid. Animals given three punished exposures to phenylacetic acid also showed increased latency to initiate mating and decreased anogenital sniff-licking with a phenylacetic acid-swabbed estrous female. However, no other measures of mating behavior were altered.

Animals↗
PubMed1975

The vocalizations of pygmy marmosets (Cebuella pygmaea).

The vocalizations from a colony of pygmy marmosets are described along with the context in which each was likely to occur. Three contact--location calls were observed to be similar in physical structure, but each appeared in a different context. The ontogeny of these contact-location calls is presented and demonstrates a greater correlation with stages of parental dependence than with chronological age. Alerting and agonistic vocalizations also are described. Many of the vocalizations show close similarity to those of other species of marmosets.

Agonistic Behavior↗