diff --git a/src/animaltrack/selection/parser.py b/src/animaltrack/selection/parser.py
index 13bd984..6c673f5 100644
--- a/src/animaltrack/selection/parser.py
+++ b/src/animaltrack/selection/parser.py
@@ -7,7 +7,7 @@ from animaltrack.selection.ast import FieldFilter, FilterAST
 
 # Supported filter fields
 VALID_FIELDS = frozenset(
-    {"location", "species", "sex", "life_stage", "identified", "tag", "status"}
+    {"animal_id", "location", "species", "sex", "life_stage", "identified", "tag", "status"}
 )
 
 # Fields that can be used as flags (without :value)
diff --git a/src/animaltrack/selection/resolver.py b/src/animaltrack/selection/resolver.py
index b2da665..7bc2ab9 100644
--- a/src/animaltrack/selection/resolver.py
+++ b/src/animaltrack/selection/resolver.py
@@ -148,7 +148,16 @@ def _build_filter_clause(field_filter: FieldFilter, ts_utc: int) -> tuple[str, l
     field = field_filter.field
     values = list(field_filter.values)
 
-    if field == "species":
+    if field == "animal_id":
+        # Direct animal ID filter
+        placeholders = ",".join("?" * len(values))
+        query = f"""
+            SELECT animal_id FROM animal_registry
+            WHERE animal_id IN ({placeholders})
+        """
+        return query, values
+
+    elif field == "species":
         # Species from animal_registry (current state)
         placeholders = ",".join("?" * len(values))
         query = f"""