Risks associated with environmental enrichment: intestinal obstruction caused by foraging substrate

Questions are occasionally asked about the safety of enrichment techniques, considering that many novel ways are frequently employed to ensure environmental complexity. A juvenile male vervet monkey was found with a phytobezoar of straw obstructing the sigmoid colon. The straw was foraging substrate, which is used in communal cages. Due to the extent of the resulting necrosis in the sigmoid and descending colon, the monkey had to be killed. This is the only individual to have suffered a harmful effect from the foraging substrate from amongst 120 vervet monkeys, which have been permanently housed on straw for over 5 years.     

LIFE HISTORY OF FRASER'S DOLPHIN, LAGENODELPHIS HOSEI, BASED ON A SCHOOL CAPTURED OFF THE PACIFIC COAST OF JAPAN

Life history of Fraser's dolphin, a little known delphinid species, was examined based on 108 specimens from a school captured by the driving fishing method in Japan. The sex ratio was approximately 1:1, and mature dolphins of both sexes formed the bulk of the school. The oldest animals were two males and a female of 17.5 yr. Age and body length at sexual maturity were estimated at 7–10 yr and 220–230 cm in males and 5–8 yr and 210–220 cm in females. Mature males were larger in body length than mature females and showed apparent secondary sexual features: deepening of the tail stock and widening and darkening of the lateral dark stripe. The annual ovulation rate was 0.49. The estimated neonatal length (110 cm) predicts a gestation period of about 12.5 mo and calving peaks in spring and probably also in fall. The calving interval was estimated to be about 2 yr. These life history parameters are similar to those of the striped and pantropical spotted dolphins, except for longevity. The reproductive rate of this species may be lower than that of other pelagic delphinids, if the observed shorter longevity is real.     

Clinical chemistry and hematology values in a Caribbean population of African green monkeys

Background Hematology and clinical chemistry (HCC) reference values are critical in veterinary practice and in vivo pre‐clinical research, enabling detection of health abnormalities, response to therapeutic intervention or adverse toxicological effects, as well as monitoring of clinical management. Methods In this report, reference ranges for 46 HCC parameters were characterized in 331 wild‐caught and colony‐bred African green monkeys. Effects of sex, weight and duration of captivity were determined by one‐way analysis of variance. Results Significant sex differences were observed for several HCC parameters. Significant differences were also observed for select HCC variables between newly caught animals and those held in captivity for 1–12 months or longer. Conclusions Comparison of this data with other non‐human primate species and humans highlights similarities and disparities between species. Potential causes of interpopulation variability and relevance to the use of the African green monkey as a non‐human primate model are discussed.     

Sexual dimorphism in growth from 8 to 18 years

A mixed longitudinal study of growth and development has been conducted, centering on an analysis of differences based on sex between the ages of 8 and 18 years for a series of 12 anthropometric indicators. The sample consisted of 50 girls and 63 boys. Proceeding from the specific differences, the variables can be divided into four groups with identical structures of differences. The first group comprises measurements of body height, body mass, shoulder width and pelvic span, all of which have higher values in boys between 8 and 10 and between 14 and 18. Between the ages of 11 and 13 girls are taller, heavier, with broader shoulders and pelvises. The second group covers measurements of subcutaneous fat. which are higher for girls throughout the period under review. The third group of indicators comprises the diameters of the joints of the extremities, i.e. of elbows and knees. Throughout the period under observation, these measurements are higher in boys, with the absolute differences between the sexes being the same at the age of 8 and ten years later. The fourth group consists of circumferences measurements of the extremities. It was found that calf circumferences manifested a specific inversion of the curves between 14 and 15, with girls showing a larger calf circumference up to the age of 14, and boys from the age of 15. The effect of earlier onset of puberty in girls was found to be reflected only on the inversion of the curve flow of the variables from the first group.     

Growth under uncertainty: The influence of marine variability on early development of Galapagos sea lions

Development implies a change in allocation of resources from somatic growth to reproduction. In a highly variable environment, growth can vary from year to year thereby influencing the long‐term life history perspective. The Galapagos sea lion (Zalophus wollebaeki) lives in a highly unpredictable marine environment in which food abundance varies not only seasonally, but also annually due to El Niño. Galapagos sea lions are restricted to a patch of cold upwelling waters surrounding the archipelago and are closely tied to land as nursing females alternate between foraging at sea and nursing ashore. Therefore, their offspring are especially vulnerable to ocean warming causing reduced food abundance. We found a significant correlation between sea surface temperature (SST) and early growth: Both mass at birth and linear growth within the first 2 mo of life correlated negatively with SST. Absolute mass gain was higher for males, but both sexes gained equally 1.9% of birth mass per day. Until the age of 3 yr male and female juveniles showed similar growth to an asymptotic mass of 40 and 35 kg, respectively. As a consequence of the highly variable environment, the plasticity in growth strategy of Galapagos sea lion juveniles appears wider than that of all other sea lions allowing them to cope with poor conditions.     

Sexual dimorphism and allometry of external morphology in Oreochromis mossambicus

Sexual dimorphism in growth of conventional morphometric characters was investigated in juveniles and young adults (size range: 31 to 91 mm) of Oreochromis mossambicus . A closely associated set of traits was identified that shows sexually dimorphic growth, which was positively allometric in the males. These traits correspond to two different morphological complexes: jaw structure and anal/dorsal fins. The best sex discriminators among this set of traits were premaxilla width, anal fin height and snout length. These findings may be explained in terms of intra– and inter–sexual selection acting together and favouring males with strong and large mouths and high dorsal and anal fins, traits that are important in agonistic displays (jaw and fins), fighting and nest digging (jaw).