14 research outputs found
Influence of early pregnancy on reproductive rate in lines of mice selected for litter size
Age at maturity in cavies and guinea-pigs (Cavia aperea and Cavia aperea f. porcellus): influence of social factors
Trillmich F, Laurien-Kehnen C, Adrian A, Linke S. Age at maturity in cavies and guinea-pigs (Cavia aperea and Cavia aperea f. porcellus): influence of social factors. JOURNAL OF ZOOLOGY. 2006;268(3):285-294.Age at maturity, a particularly important parameter in the life history of small mammals, contributes greatly to fitness. Social influences on age at maturity have been demonstrated for altricial rodents, in particular, mice. Nothing is known about such effects in precocial small mammals. Wild cavies Cavia aperea are born in a highly precocial state and mature early in life, briefly after weaning. We investigated whether the wild cavy C. aperea and the domestic guinea-pig Cavia aperea f. porcellus reach maturity earlier in the presence of adults of the opposite sex. Juvenile females kept in pairs without males showed first vaginal opening (=oestrus) when 59 days old in cavies and at about 40 days in the guinea-pig. However, in the company of adult males, cavy females kept in pairs reached maturity when about 30 days old, and guinea-pig females when 26 days old. Most cavy females experienced successful pregnancy following first vaginal opening. In cavies, female mass at birth and at first oestrus was not correlated with age at first oestrus. In guinea-pigs, birth mass predicted age at maturity only when a male was present. The growth rate from birth to first oestrus related to age at first oestrus. In the wild cavy, the presence of a male appeared to influence maturation more between days 25 and 30 than earlier in life. Male C. aperea matured and had fully descended testes when about 65-70 days old. All male cavies produced abundant motile sperm from day 75. First successful copulations occurred at about the same age. Surprisingly, the priming effect of the presence of an adult male on female maturation proved stronger in these highly precocial caviomorphs than in altricial rodents investigated so far
Oxytocin and estrogen receptor alpha and beta knockout mice provide discriminably different odor cues in behavioral assays
Application of paternity discrimination by DNA polymorphism to the analysis of the social behavior of primates
Associations among hypospadias, cryptorchidism, anogenital distance, and endocrine disruption
Animal rationality and implications for resource management: the case of biological reserves for moose and pine
Forest management, Animal behavior, Animal rationality, Q29,