The Kryonian tiger was a large, threatening predator that was endangered by the late 24th century.
In 2368, Alexander Rozhenko and Worf saw a Kryonian tiger on the protected planet of Brentalia. Alexander did not find the tiger particularly scary after it licked his hand, and he remarked that it "smelled funny". (TNG: "Imaginary Friend")
Star Trek: The Starfleet Survival Guide describes the Kryonian tiger as a large cat that lives in arctic environments.