"fierce animal" is a correct and usable phrase in written English.
You can use it when referring to any kind of wild animal, specifically one that is considered to be dangerous. For example, "The lion is a fierce animal, and he should be respected and not approached in the wild."
As Marie's suspicions deepen, she regards her husband with a fierce, animal vigilance.
"Tiger is sort of a fierce animal and is an animal that hunts alone," he said.
Some fierce animal hunger for life wipes the woman from his mind.
One of the earliest such interpretations appears in the ancient Greek bestiary known as the Physiologus, which states that the unicorn is a strong, fierce animal that can be caught only if a virgin maiden is thrown before it.
Frederick Exley, in "A Fan's Notes," described the Bednarik-Gifford encounter: I turned to see Bednarik coming from behind Gifford out of his linebacking zone, pounding the turf furiously, like some fierce animal gone berserk.... Gifford never saw him, and Bednarik did his job well.
Once again, T-Ho was a God, repelling attacks with a fierce animal agility combined with a mind of a brilliant tactician.
They are pretty fierce animals and I was a bit on edge.
This hypothesis is consistent with the argument presented in Paul Colinvaux's book, Why Big Fierce Animals Are Rare.
Children's phobias include fear of strangers among infants, fear of monsters and fierce animals in toddlers and fear of thunderstorms and bodily injury among older children.
At the time, Rojas was painting miniature dark-hearted fairy tales — girls in the woods with fierce animals — and, like many young painters, she was struck by the scale of Kilgallen's work.
As with primitive peoples who believe that eating fierce animals will make them fierce, they assume that watching quick cuts in rock videos turns your mental life into quick cuts or that reading bullet points and Twitter postings turns your thoughts into bullet points and Twitter postings.
