This is the 17761st most frequent Russian word.
укусил
"Bit" (past tense of "bite").
Here, "укусил" means actively taking a bite out of something, typically food, indicating action towards consumption.
Мальчик укусил яблоко.
The boy bit into the apple.
In this context, "укусила" refers to an act of aggression or defense where the dog bites a person.
Собака укусила почтальона.
The dog bit the postman.
"Укусил" in this sentence conveys an action performed by the wolf as a part of defending its group, emphasizing an intentional yet instinctive behavior.