Parental care and sexual interactions in Mongolian gerbils (Meriones unguiculatus) during the postpartum estrus.

The behavior of male and female Mongolian gerbils was continuously video-recorded from 24 h before the parturition to the end of postpartum estrus. We noted that the mean interval between the delivery of the last pup and the first mounting was 13 h and 32 min. Over the whole duration of the postpartum estrus (7 h and 41+/-57 min), females spent significantly more time in crouching over, pup licking, nest building and "digging" activities, and were more recipient of allogrooming than males. Maternal pup retrievals were not very frequent (14.0+/-5.6 episodes), but males never retrieved pups nor exhibited a full sequence of nest building activity. Males spent a longer mean time in bodily interactions with females, as compared to the time they spent with pups, and engaged in intense copulatory activity (592.8+/-40.5 mounts or 1 episode per 46.7s); even during the delivery process males attempted to force copulation, but females rejected mounting in all cases. We conclude that females exhibited higher levels of parental care than males, and our findings suggest that males compete with pups in attracting the female's attention, since they actively disrupt maternal care or persistently persecute the female in order to copulate.

An analysis of travel costs on transport of load and nest building in golden hamster.

We investigated the effects of travel costs on transporting nest material and nest-building activity in golden hamsters. Nest-deprived animals were submitted to run alleys 30, 90 and 180 cm long to access a source containing paper strips as nest material (Experiment 1) or were submitted to the same travel costs in 24-h experimental sessions (Experiment 2). We noted that increased travel costs were related to a decreased number of trips to the source, larger amounts (cm(2)) of nest material transported per trip (although total loads also decreased in longer alleys), longer intervals between trips, and increased time spent at the source and in nest building activity. Foraging efficiency (i.e. size of load divided by the time spent at the source) decreased as a function of travel costs, and animals transported their loads in two fundamental ways: in 30-cm alleys, they simply used their mouth to pull the paper strips, but in 90- or 180-cm alleys they transported the loads in their cheek pouches. The animals were faster when returning to the home-cage and their running speed (cm/s) increased as a function of the length of the alley, showing that animals are under different environmental pressures when searching for resources and subsequently running back with the load to the nest. Both male and female subjects were sensitive to travel costs, but males engaged in nest building activity more promptly and exhibited higher mean performances in most measures. We conclude that nest material is a good reinforcer, and our major results are in accordance with the predictions of microeconomic and optimal foraging theories.

Effects of social isolation and maternal play unresponsiveness on play fighting of juvenile golden hamsters(Mesocricetus auratus)

A brincadeira é um tipo de interação social que ocorre mais frequentemente entre animais jovens. Em roedores, constata-se que a brincadeira aumenta após um período de privação social, sugerindo que o contato físico é o elemento principal que mantém e modula este comportamento. No presente estudo foram investigados os efeitos do isolamento social e da interação mãe-filhote sobre a brincadeira de filhotes da hamsters dourado. Durante 48 horas consecutivas (pré-teste), os filhotes foram submetidos a três condições experimentais: I) completamente isolados (Isol), II) alojados somente com suas mães (Mother) e III) alojados em companhia de outro filhote do mesmo sexo e idade (Peer). Após este período, os filhotes foram transferidos para uma outra caixa-viveiro e alojados juntos a um outro animal não-familiar, do mesmo sexo e idade e que fora submetido as mesmas condições experimentais. Constatou-se que as díades Isol e Mother despenderam significativamente maior tempo em brincadeira e contato físico; as díades Isol apresentaram menor taxa de atividade locomotora, exibiram epis¢dios de brincadera com maior duração e menor tempo de latência para iniciar o primeiro episódio de brincadeira. Este estudo permitiu concluir que as mães não substituem a companhia de parceiros da mesma idade e que animais jovens isolados com adultos que não brincam podem apresentar alterações comportamentais, semelhantes às alterações exibidas por animais totalmente privados de interações sociais com indivíduos jovens da mesma espécie. Brincadeira social, privação social, interação mãe-filhote, hamster dourado

A comparative analysis of the maternal behavior and infant development of golden hamster (Mesocricetus auratus) and albino rats (Rattus norvegicus)

Maternal care is very important for infant development, mainly for altricial species such as rodents. This study was carried out in order to analyze the differences between the maternal behavior and infant development in two species of rodents regarded as gregarious and solitary. Thus, the behavior of 40 lactating females (20 golden hamster and 20 albino rat mother, or GH and AR) and their litters was recorded from the 1st to the 35th day after partirition. On the 4th day, litters were culled to 4 pups (all males or all females) and animals were grouped as follows: Groups I and II (litters consisting of all-male or all-female GH pups) and Groups III and IV (litters consisting of all-male or all-female AR pups). It was noted that GH mother spent a higher mean time in bodily interactions with pups and nest-building activity. All mothers axhibited higher pup retrievals and licked their pups more frequnatly around the 15th day, but GH mother exhibited a higher mean number of pup retrievals and licked their pups less frequantly. The emergence of pup self-licking around the 15th day coincided with the abrupt decrease in the maternal licking in both GH and mother. GH gained body mass more rapidly and their mothers lost a significant amount of body weight during the lactation, in contrast to the body weight gain by AR mother during the same period: On the 20th day, GH and AR mother exhibited 88.6 percent and 110.8 percent of their body mass, respectively, suggesting that the rearing costs are higher for GH mothers. We concluded that the behavior of animals may be explained in accordance with the differences in their habitats (desert or savanna), level of gregariousness, and also the characteristics of pup development.

Hand preference during behavioral tests and spontaneous activity in two species of common marmoset (Callithrix jacchus and Callithrix penicillata)

Hand preference in two adult C. jacchus (one male and one female) and five C. penicillata (three adult females and two 70-day-old male and female infants) was examined in this study. Animals were housed in large wire mesh cages and daily tested twice during 40 consecutive days in 15-minute experimental sessions. Tests were carried out with dog food pellets and were as follows: 1) food taking from a glass cylinder (12 cm long x 5 cm diameter), 2) food taking from an opaque plastic flask (11 cm long x 9.5 cm diameter) behind wire mesh, 3) food taking under the cage floor and 4) spontaneous activity (food manipulation, self-grooming and scratching behavior, and grasping wire mesh). It was observed that 1) subjects exhibit a high manual ability in all testing conditions, 2) hand biases occurred, but the subjects either reversed hand preference or the preference was ambiguous as the performances are examined in a longitudinal perspective, 3) hand biases were clearly more visible in test 1, which may be due to the complexity of this task itself, 4) hand biases were not similar in all testing conditions--i.e., subjects were left--in one test and right-handed in another-, and 5) the main results were very similar in both C. jacchus and C. penicillata and seem to be not dependent on either sex or age.

Investimentos em ciencia e tecnologia e mecanismos governamentais de apoio a pesquisa no Brasil

No presente artigo sao discutidos os gastos governamentais com ciencia e tecnologia (CT), a importancia das universidades para o desenvolvimento da CT e algumas peculiaridades da atividade cientifica no Brasil. Nota-se que 1) o Governo Federal, desde ha muito tempo, investe pouco dinheiro (0,7 por cento do PIB) em CT, ao contrario do que ocorre em muitos paises desenvolvidos que investem muito nesta rubrica, 2) as universidades exercem um importante papel para o desenvolvimento da CT (sao responsaveis por cerca de 90 por cento das publicacoes cientificas), a despeito de sua 'pesada' estrutura (sao excessivamente burocraticas, nao fazem avaliacao da producao academica, o ensino e privilegiado em detrimento da pesquisa, etc.) e 3) muitas dificuldades (achatamento salarial, falta de dinheiro para compra de equipamentos, livros e revistas cientificas, inexistencia de uma politica que valorize o merito academico, etc.) desencorajam fortemente a atividade do pesquisador. Dentro de uma sociedade moderna, CT esta intimamente relacionada com o crescimento e o bem-estar e isto torna necessario maiores investimentos e a criacao de uma politica governamental que estimule este tipo de atividade dentro das universidades.

Some notes on mother-infant interactions and infant development in golden hamsters (Mesocricetus auratus)

O estudo da interaçäo mäe-filhote, dentro de um enfoque ontogenético, pode esclarecer muito acerca das características e funçöes do comportamento. Assim sendo, 12 fêmeas foram observadas desde o nascimento de seus filhotes até o 25§ dia post-partum. Observou-se que: a) surtos de locomoçäo do filhote säo mais freqüentes a partir do 10§ dia - antes disso, a locomoçäo é pouco freqüente e ocorre somente dentro do ninho -; b) recuperaçöes dos filhtes atingem o seu ponto máximo por volta do 16§ dia, período em que as fêmeas mais se afastam do ninho; c) o tempo que a mäe dispende em contato físico com o filhote decai gradativamente à medida que este ganha idade; d) comportamentos que exigem um maior desenvolvimento motor (autolimpeza, brincadeira, locomoçäo e manipulaçäo de material de ninho) ou que indicam uma independência física (comer e beber) ocorrem por volta do 10§ dia de vida do filhote; e) o tempo dispendido pela mäe na arrumaçäo do ninho permaneceu bastante irregular até o 18§ dia, tendo, a partir daí um visível decréscimo; f) a auto-limpeza da mäe tem um ligeiro aumento por volta do 2§ dia e, logo em seguida, permanece constante até o final das observaçöes. Concluímos que a interaçäo mäe filho no hamster é um sistema bastante dinâmico, que evolui à medida que o filhote ganha independência

Infant kidnapping in rhesus monkeys (Macaca mulatta)

Raptos de filhotes em macacos rhesus (Macaca mulatta). O filhote primata desperta muito interesse dentro do grupo. Em algumas espécies, uma fêmea jovem ("tia") pode auxiliar a mäe nos cuidados do filhote e em outras pode ocorrer a adoçäo. Por outro lado, a mäe rhesus, nas primeiras semanas pós-parto, restringe muito os contatos sociais do filhote. Foram investigados, no presente artigo, os raptos de filhotes em macacos rhesus. Observamos que: 1. O período crítico para a ocorrência dos raptos se situa entre o 30§ e o 100§ dias pós-parto; 2. Os retornos do filhote aumentam a medida em que este ganha idade e, com efeito, säo mais freqüentes que as recuperaçöes pela mäe; 3. Fêmeas näo-lactantes raptaram mais vezes que fêmeas lactantes. Concluímos que os raptos säo importantes, pois aumentam as chances de sobrevivência do filhote, propiciam um treino de maternidade as fêmeas näo-lactantes e, a partir do interesse que o filhote desperta, facilitam a estabilidade e coesäo do grupo social de macacos rhesus