Puss Moth

The puss moth is a member of the prominent moth family (Notodontidae), a group whose caterpillars are often noted for unusual body shapes and elaborate defensive behaviors. It is native to Europe and temperate Asia, where it is one of the more instantly recognizable moths due to its thick, soft, fur-like body covering, which gives rise to the common name.

While the adult is a fairly plain gray-and-white moth, its caterpillar is one of the most unusual-looking larvae in the region: a plump green caterpillar with a raised, humped thorax, a pattern resembling a face with dark 'eye' markings, and a pair of long, whip-like tail filaments that it can extend and wave when disturbed.

The species is ecologically notable chiefly for this striking larval defense strategy, which combines a startling posture with the filament display to deter predators, making it a frequently photographed and discussed caterpillar among naturalists despite the adult moth's comparatively unremarkable appearance.

• Adult: stout, densely furry body in pale gray and white with fine black speckling and wavy dark lines across the wings, giving an overall soft, plush appearance.
• Wingspan of roughly 2 to 2.75 inches, with a heavy-bodied, rounded silhouette at rest.
• Caterpillar: bright green with a purple-brown saddle-shaped marking across the back, a raised hump behind the head bearing dark eye-like spots, and a forked tail bearing two long red-tipped filaments that can be everted and waved when the caterpillar is disturbed.
• The larva is unmistakable among European caterpillars due to its face-like humped front end and forked tail filaments; the adult is best identified by its thick furry gray coat and heavy build compared to other similarly patterned moths.

Found across Europe and temperate Asia, in woodland, riverbanks, parks, and gardens wherever willow and poplar trees, its primary host plants, are present. Adults fly at night during a single flight period in late spring to early summer and are occasionally attracted to lights.

Adults are nocturnal and, like many moths, do relatively little beyond finding mates during their short flight period. The caterpillar, feeding on willow and poplar leaves, shows one of the more elaborate defensive displays among European larvae: when disturbed, it raises and arches its humped thorax, exposing dark eyespot-like markings, while extending its forked tail filaments and waving them in a whip-like motion, a combined visual and mechanical bluff intended to startle or deter predators. It may also rear its front end in a sphinx-like threat posture during this display.

Eggs are laid singly or in small groups on willow or poplar leaves and hatch into small caterpillars that grow through several instars, developing the full humped, eyespot-marked appearance and forked tail as they mature. Mature larvae spin a remarkably tough cocoon incorporating chewed bark and wood fragments, often fixed to the trunk of the host tree, from which the moth must break free using specialized fluid to soften the casing. The species overwinters as a pupa in this hardened cocoon, with adults emerging the following late spring; there is typically one generation per year in cooler climates.