The grass is a grid of cells that regrow on their own and from their neighbours; a cell grazed bare takes a while to heal. Rabbits graze, foxes hunt rabbits, and a starving rabbit lies low half asleep where foxes do not find it. The dark holes are warrens: a rabbit that reaches one ahead of a fox is safe for a moment. Damp hollows stay green through a drought.
Every animal carries six genes: speed (fast costs energy, as speed squared), sense (how far it sees), metabolism (bigger stores and burns more), fertility (earlier and bigger litters, shorter life), caution (rabbits: how early they run; foxes: how long they chase) and coat (only colour). Young inherit the genes with small random changes, so the means drift. A fox only raises cubs when no other fox lives close by.
Mouse and touch
- tap
- drop a Hase or a Fuchs, depending on the mode
- drag
- Gras sows grass, Feuer burns it
- tap an animal
- (in the Hase or Fuchs mode) inspect its genes against the species mean
Keys
- Q W E T
- mode: Hase, Fuchs, Gras, Feuer
- space
- pause
- 1 2 3 4
- speed 1×, 2×, 4×, 8×
- D / R
- Dürre (drought) / Regen (rain), 45 seconds each
- S
- seasons: rain, normal, drought, normal, about four minutes round
- M
- migrants: a vanished species walks back in after 20 s; off, extinction is final
- C
- charts: population, gene drift, a histogram, events
- N / 0
- new random seed / reset to this seed
- ?
- this help · Esc closes panels
?seed= picks the meadow; without your taps the same seed gives the same run, tick for tick. &n= sets the width in cells (60 to 200). The link remembers speed, seasons, migrants and the charts.