World's smallest deer, weighing 1.8 kg, looks 'more like a mouse'

World's smallest deer, also known as the Java mouse-deer weighs just 4 pounds (1.8 kg) and looks more like a mouse. While an adult male deer can weigh up to 300 pounds and a female up to 125 pounds, this rare and small deer weighs just 1.8 kilograms. In comparison with a normal deer, the Java mouse-deer looks like a small rodent, making it the smallest deer. It grows to be around the size of a rabbit when fully grown, making it the tiniest living ungulate (primarily large mammals with hooves).  They belong to the Tragulidae family of even-toed ungulates, the scientific name of which is Tragulus javanicus. At birth, the Java mouse-deer weighs just 100 grams.

Java Mouse deer can be found in the forests of Java and probably Bali, though sightings have yet to be confirmed. They are most commonly found in Southeast Asia's tropical forest regions, where they live in rocks, hollow trees, and dense woods near water. Due to their small size, they are easily mistaken for rodents. In Europe, however, only 43 Java mouse-deer are left. Owing to deforestation in their natural habitats, the species is now threatened with extinction. Humans are one of the major predators that the Java mouse-deer must deal with. Humans have significantly decreased the Java mouse-deer population by destroying their habitat and killing and trapping them for food, pelts, and pets. 

There is one video of Java Mouse Deer which circulating on social media, it is from Bioparc Fuengirola zoo in Malaga, Spain. While Java mouse-deer are mainly herbivores, they have been observed in captivity eating insects as well as foliage. They are crepuscular species, which means they tend to be active at dawn and dusk when the light is dim.