Foot stamping and tail flagging in chevrotains (Tragulidae) are poorly understood behaviours often attributed to anti-predator displays or communication. We report rare wild observations of these behaviours during agonistic interactions in lesser mouse-deer (Tragulus kanchil) and greater mouse-deer (Tragulus napu) in Singapore. In lesser mouse-deer, foot drumming and tail flagging occurred during a territorial dispute between two males, accompanied by a novel pelvis-dropping behaviour potentially linked to scent marking. In greater mouse-deer, tail flagging was observed during a skirmish. These findings suggest foot stamping functions as an intraspecific signal of dominance or resource holding potential, rather than solely as an alarm signal.