A new paper by Wilson et al. (2020) explores the importance of muddy wallows to Javan rhino.

Only 72 Javan rhino (Rhinoceros sondaicuas) remain on the planet, found only in their last stronghold in Ujung Kulon National Park, West Java, Indonesia. Javan rhinos need to wallow regularly throughout the year, yet the role wallows play in their behaviour and their importance to the species remains little understood. In this study, we identified, mapped and studied 35 wallows in eastern Ujung Kulon National Park, where rhinos were active. We discovered that Javan rhino utilise wallows not only for thermoregulatory function, but also as sites of interaction and communication. This has important implications for conservation and potential translocation of rhinos, which will require finding sites with wallows and considering behavioural interactions and communication.