Lucky Beasts appear exclusively in the Kemono Friends anime, with one specific unit serving as a Kaban and Serval's window into past events at the park through pre-recorded memo-logs by Mirai as well as guiding them on their journey. Lucky Beasts are fully equipped to talk and give information on the park and all Friends registered within, but will only do so if a human is around.
The reason Lucky Beasts will not talk to Friends is due to the risk of disturbing their ecosystem, but exceptions will be made if a human is in danger inside the park.
Seeing several Lucky Beasts around at the same time is unusual, but can happen if there's a lot of Friends gathering in one place. One such occasion was the debut concert of PPP's third generation, where Friends have travelled from all over the park to watch.
Though Lucky Beasts only talks to humans, Common Raccoon was able to access memo-logs stored inside a specific Lucky Beast's memory by Mirai by using a park guide's hat. Even a simple feather from such a hat is enough for said Lucky Beast unit to register someone as their user.
Kaban's Lucky Beast
The Lucky Beast unit that helps Kaban and Serval on their journey is commonly referred to as "Lucky" by Kaban. It appears in the first episode of the anime and is part of the main cast. Lucky sacrificed their regular body to stop the Colossal Cerulean in the twelth episode, leaving behind their vitals so that Kaban could reassemble them into a compact wrist-worn version of themselves to take with her.
Lucky shows signs of sentience no other Lucky Beasts in the series has shown. Telling Serval that they had a lot of fun with her and Kaban before taking part in the final battle with the Colossal Cerulean. It's unknown if this is due to the malfunctioning nature of their body before Mirai modified them to be their personal assistant or if all Lucky Beast units have the ability to think, act and feel on their own.