Extinct in the wild: The precarious state of Earth's most threatened group of species.

Extinct in the Wild (EW) species are placed at the highest risk of extinction under the International Union for Conservation of Nature Red List, but the extent and variation in this risk have never been evaluated. Harnessing global databases of ex situ animal and plant holdings, we report on the perilous state of EW species. Most EW animal species-already compromised by their small number of founders-are maintained at population sizes far below the thresholds necessary to ensure demographic security.

Drivers of sex ratio bias in the eastern bongo: lower inbreeding increases the probability of being born male.

Parent sex ratio allocation has consequences for individual fitness, population dynamics, and conservation. Theory predicts that parents should adjust offspring sex ratio when the fitness returns of producing male or female offspring varies. Previous studies have assumed that only mothers are capable of biasing offspring sex ratios, but have neglected fathers, given the expectation of an equal proportion of X- and Y-chromosome-bearing (CBS) sperm in ejaculates due to sex chromosome segregation at meiosis.

Improving generation length estimates for the IUCN Red List.

The International Union for the Conservation of Nature (IUCN) Red List classifies species according to their risk of extinction, informing local to global conservation decisions. Here we look to advance the estimation of generation length, which is used as a time-scalar in the Red List as a way of accounting for differences in species' life-histories. We calculated or predicted generation length for 86 species of antelope following the Rspan approach.

Evaluating Conservation Breeding Success for an Extinct-in-the-Wild Antelope.

With the number of threatened species increasing globally, conservation breeding is vitally important now more than ever. However, no previous peer-reviewed study has attempted to determine how the varying conditions across zoos have influenced breeding by an extinct-in-the-wild species. We therefore use questionnaires and studbook data to evaluate the influence of husbandry practices and enclosure design on scimitar-horned oryx (Oryx dammah) breeding success, at the herd level.