Grey Long-eared Bat

Fascinating facts about the Grey Long-eared Bat

• Those ears aren't just for show — at 40 millimetres long, they're nearly as tall as the bat's entire body. A Grey Long-eared bat folds them like origami when it roosts, tucking them beneath its wings to avoid predators spotting them in caves. When hunting, it unfolds them into giant radar dishes that can detect the wingbeat of a single moth from 5 metres away in complete darkness. This asymmetrical hearing — each ear working independently — lets the bat pinpoint prey in 3D space faster than your eye can follow.
• It hunts using a technique called 'gleaning': flying slowly through forests at just 5 kilometres per hour, hovering like a hummingbird, plucking insects directly off leaves and branches mid-flight. Most bat species echolocate and chase prey through the air; the Grey Long-eared bat instead uses its enormous ears to listen for the sound of insects already sitting still. This makes it one of Europe's most precise predators, missing almost nothing it targets.
• When a Grey Long-eared bat emerges from hibernation in spring, it hasn't eaten for up to 7 months — its body temperature dropped from 37°C to just 4°C, and its heart rate fell from 400 beats per minute to fewer than 10. It survives on stored fat alone, waking occasionally to drink but never hunting. This metabolic shutdown is so extreme that a hibernating bat uses the same energy in 6 months as an active one uses in a single night.
• Females gather in maternity colonies of 50 to 200 individuals, often in the same roost for decades, and give birth to a single pup in June or July. The pup is born naked and blind, weighing just 2 grams — roughly the mass of a paperclip — and opens its eyes within days. By 4 weeks old it's hunting independently; by 8 weeks it's indistinguishable from adults. This speed of development is critical: young bats must build enough fat reserves before hibernation begins in autumn, just 5 months after birth.
• Throughout Europe, populations have crashed by 30 to 50 per cent since the 1970s, driven by pesticide spraying that empties their hunting grounds and loss of old-growth forests where they roost. Yet they persist in fragmented habitats because they're highly faithful — a bat tagged in Romania was recaptured there 34 years later, the same individual returning to the same cave night after night for three decades. This stubbornness also means recovery is possible: protect a handful of roosts and maintain insect-rich forests, and colonies can stabilise.

At a glance

About the Grey Long-eared Bat

In the whispering hours of dusk, the Grey Long-eared Bat unfurls its delicate wings, a lacy silhouette against the fading light, as it embarks on a nocturnal waltz through the forest. With large, endearing ears that rotate independently, this enchanting creature navigates the shadows, its acute hearing guiding it through a world of subtle sounds and hidden prey. As it flits and weaves, its gentle, fluttering flight belies a remarkable adaptability, allowing it to thrive in a wide range of habitats, from ancient woodlands to urban landscapes.

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