🪲 Cyclommatus metallifer

📊Overview

Cyclommatus metallifer is a slender, metallic stag famous for absurdly long, curved jaws relative to its body, and it is active and fun to watch. It is feisty and quick to pinch, and adults are short-lived (typically only three to six months), so it rewards keepers who accept a brief but spectacular adult stage.

⚡Ownership snapshot

🧭Temperament & needs

📈Compared with other Stag beetles

🧠Personality & temperament

Cyclommatus metallifer is the flashy, feisty sports car of stag beetles: a slender, metallic bronze-green beetle whose males carry absurdly long, sabre-like mandibles nearly the length of their own body. It is fast, alert, and readily throws its jaws open in a threat display, making it far more animated and combative than the heavy Dorcus. That drama comes at a price, as its adult life is very short, often only a few months.

📜Origin & background

The species is native to Sulawesi and neighbouring islands of Indonesia, where it lives in warm, humid tropical forest. Its striking long-jawed males have made it one of the most recognisable and frequently bred stag beetles in the hobby.

🏃Exercise & enrichment

This is a high-energy, restless beetle that patrols, climbs, and displays actively, so give it branches, bark, and leaf litter to roam over and grip. Abundant climbable texture matters even more here than with slower species, because a fast, top-heavy male that flips over will struggle and quickly exhaust itself without something to catch hold of.

✂️Grooming & hygiene

Care means keeping the enclosure warm and reliably humid with damp coconut fibre, misting as needed, and removing mould and old jelly often to prevent mites. The larva is the molting stage, passing through instars in fermented wood before forming a pupal cell; because this species has a fast life cycle, that cell is finished relatively quickly and must be left undisturbed to avoid deforming the emerging adult.

🍽️Diet & feeding

Adults feed on beetle jelly, with the occasional slice of banana or apple as a supplement; offer a fresh cup every one to three days and clear it once fouled. Larvae feed for only a few months on fermented hardwood substrate or kinshi, a notably short grow-out compared with larger stag beetles.

🏠Housing & environment

A single adult is fine in a warm, humid, ventilated terrarium of about 20-30 cm with a few centimetres of moist coconut fibre or fermented flake. Add cork bark, a branch, and leaf litter, and keep it warm and humid (roughly 22-28 C, high humidity) to mirror its tropical Sulawesi home, out of direct sun. Secure the lid well, since this active, agile beetle is more prone to climbing and escape attempts than sluggish species.

🩺Health & lifespan

It is hardy while conditions are warm and humid but declines fast if the substrate dries out or the room runs cool, and a dirty, wet setup quickly breeds mould and mites. Failed eclosion from a disturbed pupal cell produces crumpled wings or twisted legs, and its aggressive, active nature means males more often lose tarsi or damage jaw tips in scuffles. Even with perfect care the adult lifespan is inherently brief, commonly around three to six months, so short longevity is a feature of the species rather than a care failure.

🎓Training & socialization

Do not expect to handle this one much; it is quick, defensive, and prone to a fast open-jawed pinch. Limit contact to brief, low walk-ons over a soft surface, and be prepared for it to bolt or fly.

💰Cost of ownership

It is one of the more affordable and available stag beetles, so an adult or larva is inexpensive, and the basic terrarium and jelly cost little. The main ongoing considerations are maintaining warmth and humidity and, if breeding, buying fermented substrate, though the short larval cycle keeps grow-out costs lower than in larger species.

💚Who it's good for

Keepers who want an active, long-jawed showpiece and don't mind a short adult life.

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