Maximum longevity and juvenile mortality in zoo-housed mangabeys

Little is known about the biology of grey-cheeked and black crested mangabeys (Lophocebus albigena and Lophocebus aterrimus, respectively). As these primates face threats in the wild, well-monitored zoo-housed populations with up to date registries are becoming increasingly valuable to acquire species knowledge and to support conservation efforts. We used international studbooks to extract demographic and genetic information on 519 mangabeys to investigate how life history and parent-related variables influence maximum longevity and juvenile mortality. Generalized linear mixed models, as well as survival analyses, were applied. Results showed that females lived significantly longer than males, which is not uncommon in primates. Furthermore, our results indicated that the maximum longevity is lower for individuals living in European zoos versus individuals from North American zoos, which may be due to a combination of environmental differences and potential founder effects. We also show that the maternal maximum longevity is positively related to the maximum longevity of the offspring, which may be explained by the inheritance of "good genes". However, the age of the mother at the moment of birth was negatively related to the maximum longevity of the offspring, which contradicts literature that states that, in primates, more experienced and thus older mothers will raise their offspring better than less experienced mothers. Instead, it is more likely that an "optimal age range" exists for breeding mothers. Our study provides insights into the population biology of captive mangabeys and may be helpful for identifying future research priorities to optimize primate health and welfare directly ex situ, and indirectly in situ.

Pygmy hogs

Manon de Visser and colleagues introduce the rarest and smallest wild pig species, the pygmy hog (Porcula salvania).

Genetic consequences of long-term small effective population size in the critically endangered pygmy hog

Increasing human disturbance and climate change have a major impact on habitat integrity and size, with far-reaching consequences for wild fauna and flora. Specifically, population decline and habitat fragmentation result in small, isolated populations. To what extend different endangered species can cope with small population size is still largely unknown. Studies on the genomic landscape of these species can shed light on past demographic dynamics and current genetic load, thereby also providing guidance for conservation programs. The pygmy hog (Porcula salvania) is the smallest and rarest wild pig in the world, with current estimation of only a few hundred living in the wild. Here, we analyzed whole-genome sequencing data of six pygmy hogs, three from the wild and three from a captive population, along with 30 pigs representing six other Suidae. First, we show that the pygmy hog had a very small population size with low genetic diversity over the course of the past ~1 million years. One indication of historical small effective population size is the absence of mitochondrial variation in the six sequenced individuals. Second, we evaluated the impact of historical demography. Runs of homozygosity (ROH) analysis suggests that the pygmy hog population has gone through past but not recent inbreeding. Also, the long-term, extremely small population size may have led to the accumulation of harmful mutations suggesting that the accumulation of deleterious mutations is exceeding purifying selection in this species. Thus, care has to be taken in the conservation program to avoid or minimize the potential for further inbreeding depression, and guard against environmental changes in the future.