"Tigers Rarely Climb Trees"

Siberian tigers like the one which killed one man and mauled two others at the San Francisco zoo have been described as "powerful but ponderous".

"They don't jump very high and they don't jump very far," said Ron Tilson, one of the nation's top tiger authorities who helped write the guidelines on how to safely restrain and care for zoo tigers. "Think of a sumo wrestler" - much too massive for leaping - and that's the tiger, said Tilson, director of conservation at the Minnesota Zoo. ...

Tilson said the committee that prepared those enclosure guidelines for zoos had hundreds of years of combined experience working with tigers. Committee members took every piece of evidence about the animals' jumping ability, then added a few feet to ensure safety. "We did not want our names on a document that said this is how far a tiger jumps, and then have one clear a zoo moat," he said.

Siberian tigers have a long reach, and can stretch 12 feet from toe to toe, but when they're leaping, the waistline of their body doesn't get much farther than five to eight feet off the ground, he said. Unlike more nimble cats, they rarely climb trees.

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While the capabilities of the average tiger may be known, what is the chance of some unfortunate encountering the exceptional tiger -- the Michael Jordan of the tiger world? Tigers rarely climb trees, eh? And they can't swim either. One of the problems with measuring the true capabilities of the cats is that they think differently from human beings. We set up our tests to measure certain things. But the real action may be in what we do not measure. The Messy Beast writes:

Despite being favourite research subjects for over a century, cats are particularly challenging subjects for intelligence testing. It is hard to get them to show how they learn or what they know, especially in a laboratory setting. While social animals like dogs and horses respond to social rewards and to punishment, these are almost meaningless to cats. ...

Although cats are different from humans, it doesn't necessarily mean they don't learn in their own way. However they do it, they are sometimes capable of things they couldn't do before.

Some puzzle-boxes were quite complex. One latch required a simultaneous lift and push, and in other cages two or even three latches had to be opened in the correct sequence. Not all cats mastered these, but some did. The skills were gained gradually and Thorndike concluded "The gradual slope of the time-curve, then, shows the absence of reasoning. They represent the wearing smooth of a path in the brain, not the decisions of a rational consciousness." This is a generalisation as some cats improved abruptly and made no further mistakes even if months elapsed between tests. We describe the abrupt improvement as "the penny has dropped" or "something has clicked". One of my cats, Affy, was almost impossible to litter train despite 18 months of effort. One day she watched another cat using a litter tray and "the penny dropped"...

Engineers know that design specifications can only incorporate what we know about the range and complexity of forces to which our devices will be subjected. And they work well enough. Until a rogue wave, or an unprecedented earthquake or a rare harmonic motion sweeps them away and demonstrates that perhaps something has been forgotten.