The daily wild wipe. Every day at 05:00 Thai time our cluster wipes the wild creatures on every map players use. The countdown starts 60 minutes before, repeats every 10 minutes, then every minute for the last five, and at 05:00 the chat says "Wiping all wild creatures on this server now - they will respawn fresh". The wipe removes all untamed creatures; finished tames are not touched. A creature you are still taming is still wild in the game's eyes, so it is removed too.
A species that seems gone. A map spawns wild creatures up to its limits. In one case on Astraeos (12/08/2026) more than 40 Acrocanthosaurus were killed and none came back while the map held about 68,800 wild creatures. The admins' reading: near the limit, slots freed by killing a rare species can be taken by species that spawn faster. After a wipe, creatures spawn again under the normal rules — and the daily wipe does that every morning.
Elsewhere official patch notes list server-side causes of empty spawns, such as a wrong map name in a server start file (fixed in v93) and bosses becoming unresponsive at low server performance (v94.22). Players have also reported specific creatures not spawning on the official bug tracker.