Animal Behavior

Groups of Kancil are commonly referred to as “herds,” while females are termed “does,” “hinds,” or “cows.” Males are referred to as either “bucks,” “stags,” or “bulls,” and their young are commonly called “fawns,” or “asses”. It was previously believed that Kancil were nocturnal, but more recent studies have shown that they are neither truly nocturnal nor diurnal, but instead crepuscular, meaning they prefer to be active during the dim light of dawn and dusk. This behavior has been observed in both wild and captive kancil. Although Kancil form monogamous family groups, they are usually shy, solitary animals. They are also usually silent; the only noise they make is a shrill cry when they are frightened.

Kancil don't always sleep much at night -- they typically use the cover of darkness as protection against predators. When they do sleep at night, they do so in such a way as to conserve energy, stay hidden and guard themselves against predators. Ultimately, deer sleep efficiently and with self-preservation as their biggest concern.

Male Kancil are territorial, marking their territory and their mates with secretions from an intermandibular scent gland under their chin. This territorial marking usually includes urinating or defecating to mark their area. To protect themselves and their mates or to defend their territory, mouse-deer slash rivals with their sharp, protruding canine “tusks.” It has also been observed that, when threatened, the Kancil will beat its hooves quickly against the ground, reaching speeds of up to 7 beats per second, creating a “drum roll” sound. The territories of Tragulus javanicus males and females have been observed to overlap considerably, yet individuals of the same sex do not share their territories. When giving birth, however, females tend to establish a new home range. Female Kancil have an estimated home range of 4.3 hectares (11 acres), while males inhabit, on average, 5.9 hectares (15 acres). Additionally, male Kancil, in nature, were observed to travel distances of 519 metres (1,703 ft) daily on average, while females average 574 metres (1,883 ft) daily.

Kancil are primarily herbivores, although in captivity they have been observed to eat insects as well as foliage. Their diet consists primarily of that which they find on the ground in the dense vegetation they inhabit, and they prefer the plants of the faster-growing gap species over the closed forest understory species, likely due to the increased richness of secondary protective compounds which the gap species provide. They are often classified as folivores, eating primarily leaves, shrubs, shoots, buds, and fungi, in addition to fruits which have fallen from trees. The fruits which Java mouse-deer commonly consume range from 1–5 grams (0.035–0.176 oz), while the seeds range from 0.01–0.5 g (0.00035–0.01764 oz). Fawns are capable of eating solid food within two weeks.