Episode 226 – Java Mouse Deer: Diminutive Deer

“…and today we’re talking about a tiny deer rodent that is neither deer nor rodent. But more on that later.”

If you’re off the beaten trail in Indonesia, you may catch a glimpse of a creature more elusive than a forest gnome. You may assume it was a rat or a rabbit. But was it standing on tall, spindly legs? The bizarre Java-mouse deer is known by many names, but it’s truly in a category of its own. As a small delicate creature, the animal’s greatest defense is to be a forest phantom – a traveler of twilight. But there’s no question this tiny ungulate occupies a unique corner of Life, Death, and Taxonomy. 

Description of the Java-Mouse Deer

  • The mouse deer is exactly what it sounds like. It looks like a tiny baby deer with the head and face of a mouse – or a weasel
  • It sort of looks like it has the roundish body of a rabbit with skinny deer legs sticking out
    • It has a little deer flap of a tail
    • It even has tiny hooves!
  • It has a pointed, mousey face with large eyes, a long snoot, and rounded ears.
  • Its fur is grayish-brown, becoming lighter and oranger closer to the belly
  • The belly itself is white with white and black stripes running up its neck to its jaw
  • It would be bordering on cute, but it also has large tusks that extend downward out of its mouth.

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. We don’t have a new Measure Up intro, but we’re going to revisit our greatest hits.


  • 45 cm (18 in)
  • How many java-mouse deer go into the smallest tiger subspecies? 
  • Hint: The bali tiger is the smallest known tiger subspecies, which is now extinct. Though it was closely related to the sumatran tiger. Revised taxonomy now includes both the bali tiger and the sumatran tiger under the classification Panthera tigris sondaica.
  • 5.1 mouse-deer. Male bali tigers were 220–230 cm (90.5 inches)


  • 1 to 2 kilograms (2.2 to 4.4 lb)
  • How many java-mouse deer go into the largest serving of grilled satay?
  • Hint: Grilled satay is a dish of meat on a stick with sauce. It’s often marinated chicken. The earliest origins of satay are thought to come from Java. The record was achieved in Bali in 2010. 
  • 682.5 mouse-deer. The serving was 1,365 kg (3,009 lb 31 oz).

Fast Facts about the Java-Mouse Deer

  • Range: Lives exclusively on Java, the most popular front-end web development language. Actually, it’s the second largest island in Indonesia, with Sumatra being the largest.
    • They live in dense bamboo forests near riverbanks at relatively high elevations.
  • Diet: They mostly eat leaves and grasses but they can sometimes eat fruit, insects, and fungi.
  • Behavior
    • They tend to be solitary, territorial, and crepuscular
    • If they are scared or threatened, they’ll shriek and stamp the ground with their tiny hooves (Tiny Dancer).

Major Fact: Diminutive Deer

Chevrotains are the smallest ungulates in the world. As a tiny mammal, it’s developed several methods of survival in the dangerous jungle habitats that it inhibits. 

Its primary defense against danger is its elusive nature. Mouse deer are so elusive, they can be difficult to study. At the first sign of a researcher, they bolt to the cover of bushes, never to be seen again. 

They are usually brown, with countershading and modeled fur coloration to serve as pattern disruption. But their stealth goes deeper. Their tiny delicate hooves allow them to move through the forest silently, without trodding down crispy foliage. They also rarely make a sound, unless they are angrily drumming on the ground. Males will stomp on the ground four to seven times per second when they become agitated.

A particular species that’s native to the African tropics called the water chevrotain will jump into rivers and streams to avoid predators. It will walk along the bottom where it can hold its breath for five minutes. They like to surface near dense vegetation to see if the threat has passed. 

They are so private, that they were once thought to be nocturnal, only showing themselves under the cover of darkness. Though the night can be dangerous for a small prey animal. Instead, they are crepuscular, which means they are most active at dawn and dusk. 

One species was thought not to exist because it was never seen by researchers until 2017. The Vietnam mouse-deer was only just officially recorded when locals tipped off researchers as to where they could place motion capture cameras.

Their little tusks aren’t generally used to fight off predators. Rather, they are used to settle territorial disputes with other mouse-deer. 

Ending: So stay elusive, stay smol, and live the island life like the java mouse deer here in LDT.