Raccoons are known to chatter, trill, squeal, growl and scream. They are much more vocal as young cubs than as adults, and frequent high-pitched vocalizations from adults are a symptom of rabies.
Raccoons are especially known for chattering, a low, rapid, percussive call. They hiss and chatter at other raccoons when competing for food. They also have distress calls and vocalizations that sound like a screech owl's whistle. Territorial raccoons growl, hiss and scream.
Younger raccoons have a larger repertoire of vocalizations and make them more often. These include trills, chirps, squeals and purrs.
The raccoon sound most associated with rabies is high-pitched squeaking. Adult raccoons that repeatedly vocalize and show other odd behavior, such as staggering, should be reported to animal control.