SUMMARY: On a six-day visit (7-12 Sep 2024) with Ian Thompson to the Toloulaggo Village area on Siberut Island we saw 12 mammal species of which 11 were endemic to the Mentawai Islands, as well as another 4 species without confirmed identification. Highlights were: Golden-bellied Treeshrew, Kloss’s Gibbon, Siberut Langur, Mentawai Long-tailed Giant Rat and Siberut Flying Squirrel. We also saw what appears to be Sipora Flying Squirrel, noting that literature and databases do not include Siberut in range for this species. Siberut Island is in the Mentawai Islands off western Sumatra. We stayed in Toloulaggo village and visited only the degraded forest within 2 km of the village. Ian arranged the trip through Wawan (Arif Setiawan) of SwaraOwa; our two local guides were Ismael Saumanuk and Vinsensius Tateburuk (Vincent), assisted by Franky.