Real Komodo dragons (Varanus komodoensis) can locate carrion several kilometres away by flicking a forked tongue through the air: each fork tip samples airborne odour molecules a few centimetres apart, and the brain compares the two readings to steer toward the stronger side — a strategy called bilateral tropotaxis, the same trick sharks and snakes use to track scent and blood plumes. This lab models both halves of that system with real equations:
downwind: C(x',y') = Q / (u·√(2π)·σy) · exp(-y'²/2σy²) · exp(-x'/L)
σy(x') = spread · √x' (turbulent plume widens with distance)
L = 550 / spread (dilution length shrinks as turbulence rises)
tropotaxis: turn ∝ (C_left − C_right) / (C_left + C_right)
x' and y' are the downwind and crosswind distances from the carcass, rotated into the wind's own frame. Where the dragon sits upwind or right at the source, the plume collapses to a short isotropic near-field term instead — real plumes don't reach far against the wind. The dragon's two "tongue-fork" sample points sit a set distance apart at the tip of its snout; when both readings fall below its sensitivity threshold it switches to a random casting search (klinokinesis) until it re-acquires the plume.
- Wind speed — a Gaussian plume's concentration scales as 1/u: calm air leaves a slow, concentrated trail; strong wind dilutes it but stretches it further downwind.
- Turbulence (spread) — controls how fast the plume widens and how quickly it decays along its axis — higher turbulence means a wider but weaker cone.
- Sensitivity — the concentration floor at which the tongue can still detect a gradient; real Komodo dragons have an extraordinarily low threshold, which is why they can track carrion for kilometres.