Orlando, Florida, the once cheerful aquatic life centre of SeaWorld has been plunged into a nightmare, a nightmare from which the staff and guests of the park cannot wake up. Death stalks the park and a 12,000lb Orca whale named Tilkum is his blubbery scythe. The latest victim in this grim carnival of cetacean terror: 40 year old Dawn Brancheau.

Brancheau who worked as a trainer at SeaWorld, and had 16 years experience working with orca whales was brutally slain by the aquatic menace as horrified tourists looked on. The leviathan seized its gaoler in its monstrous jaws, submerged her and smashed her against the sides of its tank.

As well as providing family entertainment by tormenting captive marine animals SeaWorld performs an educational function. The children who witnessed the attack of February 24 received a powerful lesson in one thing – why the Orca, Latin name Orcinus orca, is known as the Killer Whale.

Sensationally it has emerged that Tilkum has killed, and killed again. The first known victim was back in 1991. Tilkum conspired with two other whales to drown a trainer at the Sealand of the Pacific park in British Columbia. The park has since shut down. Having tasted the sweet nectar of destruction it was only a matter of time before Tilkum struck again.

Bidding his time Tilkum allowed nearly a decade to pass as he swam back and forth imprisoned in his concrete aquarium. Nobody knows exactly how his next victim came to meet his grizzly end.  It was one night in 1999 that the incident occurred. The details of that night remain unclear; all that is known is that in the morning after Tilkum had a new toy in his tank, the naked, lacerated corpse of a man.

There are those that would argue that an animal cannot commit murder. That morality, right and wrong, good and evil, and indeed intelligence are the sole preserve of humanity. These people would be wrong – science has shownthat cetacean intelligence is greater than that of dogs or even primates.

Unless maddened by captivity it is unusual for the colossal water-beasts to seek human victims. Perhaps the limitless expanse of the ocean has a calming effect, perhaps it is just that there are few opportunities, but in the wild Orcas do not display the kind of homicidal behaviour that Tilkum has now.

The Killer Whale, or Blackfish as it s rarely known, have a pan-global range. Despite this these marine mammals of the family Delphinidae are becoming endangered due to the actions of man. As well as whaling activity they are placed at risk by pollution and the depletion of fish stocks. One of main dangers to the future of this species is likely to be the changes in the ecosystem of their environment caused by global climate change.