Cihelný domovník (Kuřimský)

Rarity (Jihomoravský kraj): Uncommon and highly localized; most records cluster around new residential builds on the Kuřim–Podlesí fringe during hard frosts (−6 to 0 °C). The Cihelný domovník is a medium cryptofauna (0.9–1.3 m long when extended) that appears like a collapsed bundle of rebar, slate, and brick dust until it moves. Its body is a segmented “laminate” ribbon: an inner muscular core wrapped in overlapping ceramic-like plates the color of fired clay, each plate edged with dark graphite seams. Along the dorsal line sit short, nail-like spines that resemble cut rebar ends. The head is blunt and trowel-shaped, with a ring of flexible, rubbery palps that probe mortar joints; two reflective pits act as low-light photoreceptors. Habitat & niche: It occupies unfinished masonry shells, especially hollow clay blocks. It feeds on lime, silicates, and trace organics in wet mortar, but it also “farms” warmth: the creature lines cavities with a thin biofilm rich in iron salts and carbon, promoting slow exothermic carbonation of lime. This creates faint, localized warming (often 2–4 °C above ambient) that prevents its tissues from freezing and can leave puzzling frost-free rectangles around window voids. Behavior: Mostly nocturnal, but in overcast winter mornings it may bask near upper openings where wind brings CO₂ and moisture. When threatened it performs “set-and-still”: plates lock, palps retract, and it becomes visually indistinguishable from broken brickwork. Its call is a soft, rhythmic tapping—often blamed on thermal contraction—produced by vibrating its ceramic plates against cavity walls. Strengths/weaknesses: Excellent camouflage and cold tolerance; vulnerable to prolonged dry heat and to high-vibration compaction (it dislikes plate resonance). Humorously, it shows a strong attraction to neatly stacked bricks and will “tidy” loose blocks into suspiciously perfect piles, leading workers to accuse each other of being unusually organized. Plausibility note: The ceramic plating is hypothesized to be a biomineralized composite (silica–calcium carbonate) analogous to molluscan shell formation, while the warming effect is explained by microbially mediated carbonation and iron-assisted redox cycling within its biofilm.