diff --git a/src/game/engine/scenes/headless/player_api_main.gd b/src/game/engine/scenes/headless/player_api_main.gd
index a95e726b..13d297e6 100644
--- a/src/game/engine/scenes/headless/player_api_main.gd
+++ b/src/game/engine/scenes/headless/player_api_main.gd
@@ -234,6 +234,11 @@ func _hydrate_player_api(num_players: int) -> void:
 	# `load_state_json`. Without this `events_config` is empty and no events fire.
 	_apply_events_config()
 
+	# p3-27 biosphere: stamp the fauna species library so the headless ecology phase
+	# can seed + emerge a living world. Same `#[serde(skip)]` re-stamp pattern — load
+	# AFTER `load_state_json`. Without this the ecology phase is a no-op (barren world).
+	_apply_ecology_species()
+
 
 ## p3-26 gap 2: stamp the natural-event category configs (DataLoader's merged
 ## `{category: {base_frequency, severity_weights, tiers, …}}`) onto `GdPlayerApi` via
@@ -247,6 +252,33 @@ func _apply_events_config() -> void:
 	_emit_event("events_config_api_loaded", {"categories": n})
 
 
+## p3-27 biosphere: read every fauna species JSON file and stamp the array onto
+## `GdPlayerApi` via `set_ecology_species_json`. Consumed by `mc-player-api`'s
+## `process_ecology_phase` (apply_end_turn) to build the EcologyEngine species
+## library. Mirrors the live `EcologyState` species load.
+func _apply_ecology_species() -> void:
+	const SPECIES_DIR: String = "res://public/resources/ecology/fauna/species"
+	var dir: DirAccess = DirAccess.open(SPECIES_DIR)
+	if dir == null:
+		_emit_protocol_error("ecology species dir not found — headless ecology will not tick")
+		return
+	var species_jsons: Array = []
+	dir.list_dir_begin()
+	var name: String = dir.get_next()
+	while name != "":
+		if not dir.current_is_dir() and name.ends_with(".json"):
+			var raw: String = FileAccess.get_file_as_string("%s/%s" % [SPECIES_DIR, name])
+			if raw != "":
+				species_jsons.append(raw)
+		name = dir.get_next()
+	dir.list_dir_end()
+	if species_jsons.is_empty():
+		_emit_protocol_error("ecology species dir empty — headless ecology will not tick")
+		return
+	var n: int = int(_api.set_ecology_species_json(JSON.stringify(species_jsons)))
+	_emit_event("ecology_species_api_loaded", {"species": n})
+
+
 ## p3-25: build the resource id→category map ("luxury" | "strategic" | "bonus")
 ## from DataLoader and stamp it onto `GdPlayerApi` via
 ## `set_resource_categories_json`. Consumed by `mc-turn::process_trade_phase`.
diff --git a/src/simulator/api-gdext/src/player_api.rs b/src/simulator/api-gdext/src/player_api.rs
index c3a844d7..73a06e0b 100644
--- a/src/simulator/api-gdext/src/player_api.rs
+++ b/src/simulator/api-gdext/src/player_api.rs
@@ -168,6 +168,17 @@ impl GdPlayerApi {
             .load_events_config_json(json.to_string().as_str()) as i64
     }
 
+    /// p3-27: load the fauna species library (a JSON array of per-species file
+    /// contents, e.g. `["{…grey_wolf…}","{…rabbit…}"]`) so the headless ecology
+    /// phase can build the `EcologyEngine` species library and emerge a living
+    /// biosphere. Returns the count loaded, or 0 on parse failure. Call AFTER
+    /// `load_state_json` (the field is `#[serde(skip)]`, not restored by a load).
+    #[func]
+    pub fn set_ecology_species_json(&mut self, json: GString) -> i64 {
+        self.state
+            .load_ecology_species_json(json.to_string().as_str()) as i64
+    }
+
     /// Stamp the runtime `UnitsCatalog` (id → `UnitStats`) onto the held
     /// `GameState`. Distinct from `set_units_catalog_json` (which loads the
     /// tactical `ai_unit_catalog`): this is the same `mc_units::UnitsCatalog`