Killer whale
From Memory Alpha, the free Star Trek reference.
The killer whale (Orcinus orca) is an aquatic mammal indigenous to Earth. It is a cetacean species.
When Spock tried to match the sound of the whale probe to the sound of an Earth animal aboard the Klingon Bird-of-Prey HMS Bounty, a killer whale was one of the lifeforms shown. (Star Trek IV: The Voyage Home)
Three huge models depicting a killer whale family were on display in the Cetacean Institute in San Francisco in 1986. (Star Trek IV: The Voyage Home)
In 2293, Captain James T. Kirk's quarters aboard the USS Enterprise-A featured a black and white painting of a pair of killer whales. (Star Trek VI: The Undiscovered Country)
