AT A GLANCE
- Common Name: Long-tailed Planigale
- Scientific Name: Planigale ingrami
- Category: Mammals
- Subcategory: Marsupials
- Range: Northern Australia, widespread across the Kimberley in Western Australia, the Top End of the Northern Territory, and western Queensland
- Habitat Type: Seasonally flooded blacksoil plains, claypans with deep shrinkage cracks, tussock grasslands, and alluvial river floodplains
- IUCN Red List Status: Least Concern
- Lifespan: 1 to 2 years
- Diet: Carnivorous/Insectivorous (crickets, grasshoppers, centipedes, spiders, and small lizards, occasionally tackling prey larger than itself)
- Average Size/Weight: Head-and-body length 55 to 65 mm; tail length 55 to 60 mm; weight 3.9 to 4.5 g (the world’s smallest living marsupial)
- Key Defining Feature: Diminutive, shrew-like carnivorous marsupial with an impossibly flattened, triangular skull barely 3 mm deep, adapted to navigate deep soil cracks
Overview
The Long-tailed Planigale (Planigale ingrami) holds the extraordinary zoological distinction of being the smallest living marsupial in the world, often weighing less than a single teaspoon of sugar. Belonging to the carnivorous marsupial family Dasyuridae, this diminutive predator is native to the vast, cracked clay plains of tropical northern Australia. Despite its microscopic size, it is a ferocious, hyperactive predator capable of subduing venomous centipedes and crickets nearly twice its own mass.
Biology and Physical Characteristics
Planigale ingrami weighs a mere 4 grams, with an elongated, slender body and soft grey-brown to cinnamon dorsal fur that shades to pale cream on the underbelly. Its skull represents one of the most extreme anatomical specializations among mammals: severely compressed dorsoventrally, its entire skull measures less than 3 to 4 millimeters in vertical thickness. This flat, triangular head, coupled with an exceptionally flexible spine and tiny limbs, allows the animal to squeeze through microscopic soil fissures that are completely impenetrable to any predator or competitor.
Behavior and Ecology
A nocturnal and crepuscular dynamo, the Long-tailed Planigale spends the scorching heat of the Australian dry season deep inside the labyrinthine shrinkage cracks of blacksoil plains, where humidity remains high and temperatures cool. At night, it scurries through these subterranean fissures with blinding speed, using its sensitive tactile whiskers and keen sense of smell to locate spiders and grasshoppers. When attacking prey, it leaps with relentless ferocity, pinning the quarry down with its forepaws and delivering rapid, crushing bites to the head with needle-sharp premolars.
Conservation and Human Impact
The Long-tailed Planigale is evaluated as Least Concern by the IUCN Red List. It remains widespread and locally abundant across millions of hectares of pastoral and indigenous lands in northern Australia. Its subterranean microhabitat shields it from surface bushfires and aerial predators, although habitat degradation from intensive cattle trampling of soil cracks poses localized challenges.
Interesting Factoid
The Long-tailed Planigale is the smallest marsupial on Earth, weighing less than a nickel, and its skull is squished so flat that it can squeeze through a crack thinner than a coin.