R A SMUS GR E N HAVMØL L E R, JU N A I D I P A Y N E, WI D O D O RAMONO, SU S I E E L L I S, K . YO G A N A N D, BA R N E Y LO N G, ER I C DI N E R S T E IN, A. CH R I S T Y WI L L I A M S, R U D I H . PU T R A, JAMA L GAWI, BI BHA B KUMAR T A L U K D A R and NE I L B U R G E S S
Abstract The Critically Endangered Sumatran rhinoceros Dicerorhinus sumatrensis formerly ranged across Southeast Asia. Hunting and habitat loss have made it one of the rarest large mammals and the species faces extinction despite decades of conservation efforts. The number of individuals remaining is unknown as a consequence of inadequate methods and lack of funds for the intensive field work required to estimate the population size of this rare and solitary species.