Thomas' Flying Squirrel

Fascinating facts about the Thomas' Flying Squirrel

• Thomas' flying squirrel doesn't fly—it glides by stretching a membrane called a patagium between its front and back legs, transforming its body into a living wing. A single leap from a rainforest canopy can carry it 60 metres horizontally, the length of two Olympic swimming pools, before it lands feet-first on a tree trunk 15 metres below where it started. The membrane acts like a parachute and rudder combined, letting it steer mid-air by tensing different muscle groups. Most glides end in a steep climb up the landing tree—momentum and physics working together so the squirrel doesn't waste energy walking back up.
• At roughly 130 grams, Thomas' flying squirrel is built for stealth rather than strength, with a skeleton so light it approaches the theoretical minimum for a mammal its size. Their bones are hollow like a bird's, their organs compressed, their fur so dense it takes water hours to reach the skin. This extreme lightness means they can land on branches too thin to support a terrestrial squirrel, accessing food and shelter in the thinnest outer canopy where predators struggle to follow.
• Thomas' flying squirrels are nearly invisible in the dark—they're nocturnal and have eyes so enlarged they dominate the skull, giving them vision in light levels 1,000 times dimmer than what humans need to see. The reflective layer behind their retinas (the tapetum lucidum) catches every photon twice, a built-in amplifier that turns the rainforest night into navigable space. They hunt insects on bark and pluck fruit from branches in near-total darkness, a precision that would be impossible without this specialised optics.
• The patagium isn't just stretched skin—it's laced with muscles, tendons, and a unique bone called the styliform cartilage that extends from the wrist like a strut, keeping the membrane taut during glides. Evolution extended their limbs and fingers without losing dexterity; they can still grip, climb, and manipulate small objects with shocking precision. This hybrid anatomy—part wing, part limb—solves a problem that stumped other gliding mammals: how to be both a strong climber and an efficient glider.
• Thomas' flying squirrels live in the darkest, wettest layer of Southeast Asian rainforests where fruit is patchy and insects are the reliable protein source. They've adapted a generalist diet that lets them survive when seasonal fruiting fails, and their small size means they need far fewer calories than larger canopy dwellers. This flexibility, combined with their ability to exploit the outer canopy where few competitors venture, keeps them common across their range—a survival strategy that works precisely because it asks less of the forest than more specialized neighbours demand.

At a glance

About the Thomas' Flying Squirrel

In the velvet darkness of the tropical forest, a whispered rustle signals the emergence of Thomas' Flying Squirrel, its large, round eyes shining like lanterns as it stirs from its daytime slumber. With a soft whoosh, it launches itself into the night air, its patagium - a membrane of skin stretching from wrist to ankle - billowing like a sail as it glides effortlessly between the trees, a master of the forest's hidden pathways. As it soars, the moonlight catches the squirrel's silky fur, imbuing it with an ethereal glow, like a phantom navigating the shadows.

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