The endangered proboscis monkey (Nasalis larvatus) is a sexually highly dimorphic Old World primate endemic to the island of Borneo. Previous studies focused mainly on its ecology and behavior, but knowledge of its vocalizations is limited. The present study provides quantified information on vocal rate and on the vocal acoustics of the prominent calls of this species. We audio-recorded vocal behavior of 10 groups over two 4-month periods at the Lower Kinabatangan Wildlife Sanctuary in Sabah, Borneo. We observed monkeys and recorded calls in evening and morning sessions at sleeping trees along riverbanks. We found no differences in the vocal rate between evening and morning observation sessions. Based on multiparametric analysis, we identified acoustic features of the four common call-types "shrieks," "honks," "roars," and "brays." "Chorus" events were also noted in which multiple callers produced a mix of vocalizations. The four call-types were distinguishable based on a combination of fundamental frequency variation, call duration, and degree of voicing. Three of the call-types can be considered as "loud calls" and are therefore deemed promising candidates for non-invasive, vocalization-based monitoring of proboscis monkeys for conservation purposes.
Year 2020 has brought the greatest global pandemic to hit the world since the end of the First World War. The severe acute respiratory syndrome coronavirus 2 and the resulting disease named coronavirus disease 2019 has brought the world to its knees both financially and medically. The American Society of Primatologists has postponed their annual meetings from the end of May 2020 until the end of September 2020, while the International Primatological Society have postponed their biennial congress from August 2020 to August 2021, which has also resulted in their 2022 meetings in Malaysia being pushed back until 2023. Here, I explore the potential dangers of pursuing any primate fieldwork during this pandemic on our study species, their ecosystems, and local peoples. I believe that the risk of bringing this virus into our study ecosystems is too great and that primatologists should cancel all field research until the pandemic ends or a vaccine/reliable treatment is widely available. This is the year we all must become One Health practitioners!
Microsatellite markers were developed for Johannesteijsmannia lanceolata to assess the genetic diversity and mating system of this alarmingly endangered species.
Indo-Pacific humpback dolphins (Sousa chinensis) are documented from various locations along Borneo's coast, including three sites in Sarawak, Malaysia, three sites in Sabah, Malaysia, three locations in Kalimantan, Indonesia and the limited coastal waters of the Sultanate of Brunei. Observations in all these areas indicate a similar external morphology, which seems to fall somewhere between that documented for Chinese populations known as S. chinensis, and that of Sousa sahulensis in Australia and Papua New Guinea. Sightings occur in shallow nearshore waters, often near estuaries and river mouths, and associations with Irrawaddy dolphins (Orcaella brevirostris) are frequently documented. Population estimates exist for only two locations and sightings information throughout Borneo indicates that frequency of occurrence is rare and group size is usually small. Threats from fisheries by-catch and coastal development are present in many locations and there are concerns over the ability of these small and fragmented populations to survive. The conservation and taxonomic status of humpback dolphins in Borneo remain unclear, and there are intriguing questions as to where these populations fit in our evolving understanding of the taxonomy of the genus.