Keeping the Tiger in the Tank

The report (http://www.guardian.co.uk/international/story/0,,2232328,00.html) that a 135 kg Siberian or Amur tigress, Tatiana, had escaped from her enclosure (protected by 6M walls and a 'deep' moat) at San Francisco zoo near closing time on Christmas day and had mauled 3 young men (one of them fatally) is sad on several levels. Although the story resulted in the media listing other injuries and fatalities caused by escaped zoo animals, on a visitor per hour basis, visiting a zoo must be one of the safest of human activities. It is, of course, important to note that tigers can and do swim well (the moat may not have been much of a problem) and that a 6M wall may not be insurmountable (especially if there was something the animal could use to launch its leap in the enclosure). The tigress was, predictably, shot dead when she 'turned towards' approaching policemen which is unfortunate as there are reportedly only around 400 Amur tigers in the wild. This occurrence may cause zoos to think again about keeping these potentially lethal animals but the question then arises, how will they survive anywhere? There is a suggestion that one of the human victims 'teased' the tigress by dangling his leg over the wall (perhaps providing a 1M 'leg up'). There were calls to make zoos 'safer' but the situation was rendered more complicated by a media report suggesting that the wall had 'shrunk' to 'a few inches' under 4M. As 4M is the minimum recommended height for tiger enclosures in that part of the US, it was suggested that the zoo's licence could be revoked.