The Mouse Deer, also known as Chevrotain, is a really peculiar little ungulate. Captivating and elusive in equal measure. They belong to two genera ‘Tragulus‘ and ‘Moschiola‘, which are members of the ‘Tragulidae‘ family. This is the only family in the infraorder ‘Tragulina‘, which falls under the order ‘Artiodactyla‘ which is mostly made up of similar, though generally larger ungulates.
There are ten recognized species of Chevrotains, each with its unique characteristics, adaptations, and habitats which span across South East Asia and a few specific regions of Africa. The Chevrotain family line is ancient, tracing roots back 34 million years, and in this time the creatures have remained relatively unchanged.
Appearance & Characteristics of the Mouse Deer
Mouse Deer are renowned for their small and delicate stature, with the Java Mouse-deer being the smallest, weighing around two to four pounds, and the Water Chevrotain (Hyemoschus aquaticus) being the largest, weighing up to 25 – 33 pounds. They possess a round, almost rodent-like body, hooved feet resembling those of a piglet, and a face akin to a mouse.
This gives them the appearance of a charming mix of various animals. Despite their slight size, they are full of spunk and zest. While male cervus deer have antlers, mouse-deer males have long tusk-like incisors. They use these in much the same way, for territorial displays and fighting, serving mostly as a defence mechanism.
Individual species have some quite peculiar traits. The African species for example, shows a unique affinity with the water, displaying confident aquatic skills to escape predators. Remarkably, they can stay submerged for up to four minutes walking along the bottom of streams or rivers to evade danger.
Distribution – Location and Habitat
Mouse deer are found across a wide range of Indonesia, South and Southeast Asia, with one disconnected species native to Central and West Africa. While there are only 10 extant species today, there used to be many more, and the solitary African species was joined by more relative in the now extinct genus ‘Afrotragulus‘.
Individual species have their own range, and some of the countries and islands they can be found include Sri Lanka, India, Java, Thailand, Vietnam and Myanmar. The Water Chevrotain (Hyemoschus aquaticus) is found in Central and West Africa, from Sierra Leonne to Uganda.
Today, they predominantly inhabit forested areas, where they have adapted well to the environment. Secondary Rainforest, wet-zones and dense forest where there is plenty of food and cover are their preferred habitats.
The Lifestyle & Behaviour of the Mouse Deer
Mouse deer are known for their solitary and secretive nature. They tend to live alone or in small family units, avoiding larger herds or social structures. They don’t like attention and are always on the look out for threats. As such, they are adept at moving quietly through their habitats, making use of dense vegetation to stay hidden.
Depending on the species, mouse deer exhibit both diurnal and nocturnal behaviours. They communicate using a variety of different calls, body signals and scent marking. Vocalizations include whistles, screams, or barks, which are used for a variety of situations, such as to call others to alert or during mating interactions. Scent marking is also a crucial aspect of their communication, especially for establishing territories.
Male mouse deer are known to be territorial, and will mark their boundary using scent glands located near their eyes. They use these territories for feeding and attracting females during the breeding season. They will chase off and fight competitors using their elongated canine teeth (or tusks), to defend their territories and secure mating rights.
Diet & Nutrition of the Mouse Deer
Mouse Deer are primarily herbivorous, relying on a diet consisting mostly of various plants, fruits, and fungi found in their habitats. They do not hunt but rather forage for food, utilizing their keen senses to find nourishment, and their small size allows them to navigate through dense vegetation to access food sources.
In some cases they have been known to eat small vertebrates and insects, but this seems to be only when other food is scarce or competition for food is great. It is exceptional and not the norm.
Predators & Threats to the Mouse Deer
Due to their small size, mouse deer (Chevrotains) are vulnerable to a variety of predators, including birds of prey such as eagles and larger mammals. They employ their agility, camouflage, and, in some cases, aquatic skills to evade threats, but they are ultimately a prey species and there are many predators about.
Specific predators do vary depending on their habitat and range, but crocodiles, tigers and other big cats across the range, snakes and in some cases, particularly the Java mouse-deer, dogs are also a threat.
The Mouse Deer Reproduction
Mouse deer typically exhibit a polygamous mating system, where a single male mates with multiple females. The mating and breeding season of mouse deer can vary depending on the species. Some, such as the lesser Malay chevrotain (Tragulus kanchil), do not have a specific breeding season and can mate year-round. Others may have more defined breeding seasons, often coinciding with optimal environmental conditions that favour the survival of the offspring.
Female does, once impregnated, have a gestation period that can range from 4.5 to 6 months, depending on the species. The water chevrotain (Hyemoschus aquaticus), are quite unique amongst the species, in that they have a postpartum estrus. This means they can conceive again shortly after giving birth.
Typically, the female doe will give birth to a single fawn, although twins can also occur. The fawns are precocial, meaning they are relatively mature and mobile shortly after birth as is common with most ungulates. They are usually born in a secluded spot, providing safety from predators. The mother hides her fawn in dense vegetation and visits it for nursing. Parental care in mouse deer is primarily provided by the mother.
Young mouse deer fawns grow relatively quickly compared to other ungulates. Depending on the species, they can reach sexual maturity as early as 5-6 months of age.
Lifespan of Mouse Deer
By some accounts, mouse deer are estimated to have the capacity to live up to 14 years in the wild. The Lesser Malay Mouse Deer averages around 12 Years whereas the Philippine/Balabac Mouse Deer can live up to 14 years. On average across the species though, it is closer to 10 years.
In captivity, these little ungulates have been recorded as living as long as 16 years, and as little as 6 years, but it would appear as though lifespans either in captivity or the wild are fairly similar.
Population and Conservation
Chevrotains face varying levels of conservation concern, with some species previously believed to be extinct but later rediscovered – specifically the Silver-backed Chevrotain. All species are listed on the IUCN red list, with status ranging from Data Deficient, to Least Concern to Endangered. The Philippine/Balabac Mouse Deer (Tragulus nigricans) is the most at risk, and the only species currently listed as ‘Endangered’, but the population of many more species is in decline.
Is a Mouse Deer a rodent or a deer?
Despite the name ‘Mouse Deer,’ Chevrotains are not rodents, but they are not deer either. Mice belong to the order ‘Rodentia‘, whereas both the deer and the mouse deer belong to the order ‘Artiodactyla‘. Deer are members of the ‘Cervidae’ family, whereas Chevrotains are members of the ‘Tragulidae‘ family. They are however small ungulates, and as such are more closely related to deer than to mice.
Which Mouse Deer has fangs?
While many deer grow antlers, and use these to fight, as well as a display of status and position, the mouse deer does not. Instead, male mouse deer (Chevrotains) across various species, grow long tusk-like incisors that commonly get referred to as ‘fangs’ because of the appearance they take as they grow. These are used in fighting and dominant displays, a unique feature among these small ungulates.
5 Fun Common Mouse Deer Facts for Kids
- Mouse Deer have a face like a mouse but limbs like a larger ungulate, making them look like a cute mix of different animals!
- Rather than antlers that you get with large deer, many grow tusk-like ‘fangs’! Especially the males, which use them for fighting.
- Some Mouse Deer can stay underwater for up to four minutes to escape predators!
- They are the smallest ungulates in the world, with the smallest species weighing only about two to four pounds (1-2 Kg).
- They are not actually mice or deer but as they are ungulates, they are more closely related to deer.
Mouse Deer Species Table
|Tragulus kanchil (Lesser Malay Chevrotain)
|As small as 45 cm long (head and body),
|Small, round body, mouse-like face,
Tusk-like incisors in males
|Hyemoschus aquaticus (Water Chevrotain)
|Up to 85 cm long (head and body), 35 cm tall at shoulders
|Larger, aquatic adaptations,
Can stay submerged to escape predators
|Tragulus napu (Greater Malay Chevrotain)
|70 to 75 cm long (head and body), 35 cm tall at shoulders
|Larger than T. kanchil, similar appearance,
Solitary and nocturnal
|Moschiola meminna (Indian Spotted Chevrotain)
|India, Sri Lanka
|55–60 cm long (head & body)
|Small, spotted or striped coat,
Adapted to dense forests
|Tragulus javanicus (Java Mouse-deer)
|Southeast Asia – Java, possibly Bali.
|45 cm long (head & body) , 30 cm tall at shoulders
|Prefers riverine and lowland forests.
Smallest extant ungulate in the world
|Tragulus williamsoni (Williamson’s Mouse-deer)
|52.5 cm (head & body) based on limited data
~ Weight data unclear
|One of the smallest species,
Elusive, inhabits dense forests
|Tragulus versicolor (Silver-backed Chevrotain)
|Average 48 cm (head & body) based on limited data
~ Weight data unclear
|Rediscovered species, thought to be extinct, elusive
|Moschiola kathygre (Yellow-striped Chevrotain)
|43–51 cm (head & body)
3.1 – 3.8Kg
|Similar to M. meminna, but with distinctive yellow stripes
|Tragulus nigricans (Philippine Mouse-deer)
|40–50 cm (Head to Tail) up to 18cm tall at the shoulders.
~ Weight data unclear
|Small, dark-colored, adapted to various habitats
|Moschiola indica (Indian Mouse-deer)
|Up to 57.5 cm (head & body) with a 2.5 cm tail.
~ around 3Kg
|Similar to other Moschiola species, adapted to dense forests