Of Tiger Walls and Tragedies
Thoughts on the San Francisco Zoo Tiger Incident
By Tim Stoffel, December 2007

It did not take long for the story of the tiger escape at the San Francisco Zoo on Christmas Day 2007 to be national headlines. Of course, this incident has been raised to the point of sensationalism. It has been like throwing 'white Tofu to the animal rights radicals' who are already demanding the tiger exhibit be permanently closed. Although this is a tragic incident, the fact that such incidents are very uncommon is being ignored by the press. So, instead of focusing on what went wrong at the SF zoo that day, this paper will try and examine what didn't go wrong, and show that there were other forces at work that inadvertently (or intentionally) have added up to make this situation that much worse.

The first thing I want to point out is that a number of people died on Christmas Day in San Francisco. I do not have exact statistics, but I am sure there were some fatal car accidents in the Bay area. There are fatal accidents every day, and these kinds of accidents do not take breaks on holidays. But, did you hear of any of them in the news? No, you probably didn't. Are the people killed in these accidents any less dead than the boy killed by the tiger? No. It is also very likely the boy who was killed in the tiger attack suffered less then do many vehicle accident victims. You don't hear about that, either.

There are two persistent 'observations' about this incident that keep coming out, and are very likely the truth.
1.) The men were taunting the tiger, and
2.) The tiger escaped by jumping a moat wall.

Lets look at number 1 first. You cannot design anything that can prevent every accident every time when the cause is deliberate human stupidity. In the weeks before this incident, there was a man killed in a zoo in India because he crossed over the barrier fence, to try and get a better picture of a tiger. He was being warned not to cross the fence by officials, but did so, anyway. He stuck his hand and camera inside the fence. Both tigers then attacked him. A day or two later, a young girl crossed the barrier at another zoo in Malaysia, and gets clawed by a leopard. The parents were there and did not stop the girl. Unlike this country, the zoo can press charges against the parents for failure to properly control their child. Then, just 5 days after the fatal incident in India, another man jumps into a tiger enclosure at another zoo in India. This man escaped with fairly minor injuries, but he was dragged around a bit by a tiger. Turns out this is the second time in a year that this man has done this.

The point of all of this is they human stupidity can trump the best enclosure design. The only way to make a tiger exhibit completely safe from idiots is to not build it. And, I can think of plenty of good reasons to build a tiger exhibit despite the idiots.

Now, let’s take a reasoned look at number 2. The San Francisco Zoo's tiger 'grotto' was built in the 1940's. This was at a time when most zoos were keeping their big cats in barred cages. This exhibit was nearly two decades ahead of its time when it was built, and was undoubtedly quite a sensation. One of the unique features of this exhibit was the use of a 'dry moat'-- a feature that eliminated the need for any kind of a visible barrier between the animals and the general public. The moat is 33 feet across-- farther then even the most athletic tiger could ever jump. The tigers could go down into the moat-- probably planned as a safety feature if one did try to jump-- and get back out again via a set of 'tiger stairs'. The front wall of the moat, the wall everyone is concerned about, is 12.5 feet high.

Conventional wisdom says that a lion can jump 12 feet straight up. Seeing that lions and tigers are nearly identical internally, it follows that a tiger can do this as well. Knowing this, the height of the wall was set just a little higher than the big cats could jump. And, this wall worked as the designers intended for nearly 70 years. Few zoo exhibits anywhere have been in existence for 70 years, so this is a pretty good safety record. Also consider this wall has been inspected over and over, and approved by certifying agencies for many years. Now, let’s consider the current standards:
The Association of Zoos and Aquariums (formerly the American Zoo and Aquarium Association or AZA) has an enclosure height standard of 16.4 feet, which just happens to be exactly 5 meters!. Its interesting that they would have picked such a round number (in metric, nonetheless!). This suggests to me that their standard is unnecessarily high. The other zoo accrediting body in the US, the Zoological Association of America (ZAOA) has a height standard of a 12 foot straight fence, or 10 foot, with a two foot recurve section (total 12 feet). This same organization has a 10 foot fence, with a four foot recurve (total height 14 feet) for an enclosure that houses cougars. The purpose of the recurve is that a cat cannot readily climb a fence while partially upside down. They are less inclined to jump at such a fence, as there is nothing under it to 'scramble' on. Lions and tigers are not good climbers, but cougars are. That is why the fence requirements are greater for a cougar. The ZAOA does not make any additional distinctions for a moat wall vs. a fence, other than moats have to be approved on a case-by-case basis.

The Feline Conservation Federation (FCF), is a group that represents many smaller facilities and private keepers of big cats. They are a fairly new group in the accreditation business. They have a requirement in their 'model regulation' of a 12 foot vertical fence, topped by either a 2 foot recurve section (total height 14 feet), or two runs of electricified 'hot wire'. Moat walls are not specifically discussed in the FCF regulation, as this kind of expensive construction is beyond the scope of most facilities that would be seeking accreditation from them.

In all fairness, a fence and moat wall is actually different 'animals' when it comes to confining a big cat. A 12 foot fence is going to be very difficult for a cat to jump, as they can see that there is nothing on the other side. Thus, if they jump up to the top, it is a long distance down on the other side. Even with the small flat area at the top afforded by a recurve, they cannot perceive this as a 'landing zone' because it is projecting out from an already tall wall. Even if a cat could get a paw on to the fence edge, the dynamic forces of the cat's momentum, along with the natural give of a fence, would make it very difficult for it to hang on. A moat on the other hand, typically has a flat area at the top big enou8gh for the cat to 'land'. Thus, a fence is potentially more effective at keeping a cat in, than a moat wall of the same height. But given these statistics, how high does a moat wall really have to be?

Apparently, tigers have been unsuccessfully testing this moat wall for years. About 10 years ago, a zoo visitor saw a tiger actually get a paw on the ground just over the moat wall edge. Upon asking a nearby keeper about this, the keeper remarked 'she does that all the time. She hates my guts'. This zoo patron resigned her membership over this, but never heard back from the zoo. Apparently, no changes were made. Today, this is being used as a 'case' to show that zoo officials knew the wall height was inadequate. Or, was it? No tiger did escape in the ten years that followed. And, apparently, the keepers who knew about this felt that the tigers never got a firm enough grip to pull themselves out of the moat.

Now, we fast forward to Christmas Day 2007. Few details of what exactly happened have been made public, even though there are two living eyewitnesses. The articles have indicated that these two men apparently involved in the escape (and both heavily injured), have been uncooperative. Both men have a record of petty crimes. The facts that have been made public and not refuted so far do indicate that these men were most likely
1.) over the barrier fence (which is typically only a few feet high in most zoos, as most visitors know better than to cross a fence in front of a potentially dangerous animal) , and
2.) doing something to antagonize the tiger.
So, an angry tiger is in the moat, and is eying her 'tormenters'. She makes a super-tiger jump to get at them, and finds that she has gotten enough momentum to clear the moat wall. She manages to scramble out and attack one of these men.
There has been conjecture that the tiger may have had some help. A board or a rope may have been used to either entice the cat, or arrange for a deliberate escape. Another theory suggests that the tiger may have been able to grab a low-hanging tree branch and pull herself out. Regardless of how the cat got out, it likely required considerable extra effort on her part.

When the tiger was examined after it was shot, it was found to have 'wear on its back claws'. This suggests that this tiger may have been 'testing' this wall before the incident. Most likely, she had been 'testing' the wall for some time. But, she had never been able to get out. But under these circumstances, with a couple of belligerent young men being where they were not supposed to be, likely yelling and throwing objects at the cat, it was enough to get her angry enough to make this 'extra effort' jump. Thus the tiger, had it not bee provoked, would have likely not been able to jump the wall. I conclude that the escape was a result of a combination of unlikely things, most importantly, a tiger that had been riled up by egregiously misbehaving zoo visitors.

So, how high does that moat wall have to really be to prevent an escape? The vast majority of the time, 12. 5 feet. Under extraordinary situations like this, I bet six additional inches would have been all that was needed to prevent this escape. Or, a hot wire or two along the top edge of the moat.
It is hard to call the zoo negligible for a moat wall that has successfully worked for nearly 70 years!
Now, lets look at something else that didn't work that day, but most likely worked as well as it could have-- the zoo's emergency plan.

Emergency plans are great things. Most businesses have them. But, do the plans work? Short of an emergency, they are rarely tested. Furthermore, emergency plans are written to cover the most likely emergencies. The only emergency plans that truly work are those that are tested regularly with well-designed drills. Few businesses spend a lot of time doing drills, as this eats into employee productivity and the bottom line. Drills that are repeated too frequently also tend to lose their effectiveness, as people get bored with them.

The zoo is under heavy criticism for its emergency plan not working. But look at the circumstances. It was Christmas day. It was towards the end of the day. It was growing dark. I am sure that the staff at that time was the minimum needed to keep the zoo open so that as many as possible could be home with family. Those that were on duty were not likely the 'first string' staff. The veterinary staff, the ones that could tranquilize an escaped animal, was likely not there that day. The members of the 'shooting team' refereed to in the press were probably not there, either. This is the worst possible situation in which to have a major emergency occur. But, it is at times like this when really off-the-wall emergencies seem to occur.

The failure of the emergency plan to not function is understandable under this extraordinary situation at the worst of times. But what is even more extraordinary is the response of the city Government. Their reaction is typical of a Governmental body. They have no grasp of what goes on day-to-day at a zoo. They seem to believe that something can be 100 percent foolproof. And, if something is not 100 percent foolproof, they believe that it can be made 100 percent foolproof. They call into question decisions made years ago (transferring the operation of the zoo into private hands), that very likely had no bearing on the current situation. In fact, I will surmise the zoo staff's response may have been worse had it been staffed by Government employees who were operating under considerably more bureaucracy.

Based on what has been reported in the press, the retribution of the city's Government against the zoo is likely to be severe. I bet that between the AZA, and the various Governmental bodies interposing themselves in this disaster, if the zoo doesn't end up hidebound with new regulations and requirements that will actually result in a greater likelihood of a future accident. And significantly degrade the zoo visitor's experience when visiting the zoo. Only time will tell if cooler heads will prevail.

Last but not least, is the police who shot the tiger. In a life-and-death situation, protecting people comes first. But, there seems to be a tendency in situations like this for 'the police to play with their guns'. Most versions of the story report that the tiger, when it was distracted, started coming on to the police officers. Shooting the cat in this situation is understandable, and fully justifiable. Another version of the story reports that the officers were distracting the cat with the full intent of wasting it when it was clear of the victim. The life-and-death situation in mind, if there was any reasonable chance that an endangered animal like this tiger could have been safely contained, it should have been. But, I would not be surprised if the police had not yet talked with zoo staff yet, to see what is possible.

There is a reason I am being so critical of the police reaction in this situation. There seems to be a tendency of police to be 'trigger happy' when dealing with animals. A recent incident involves police responding to the home of a man. When the man opened the door, he was with a big German shepherd dog. Even though the dog made no threatening moves, the officer just shot it. Luckily in this case, the dog survived. In another case, police were shooting at a snake in a tree. Hardly a dangerous situation. One of the stray shots hit a child who was in a boat on the other side of some bushes (this was by a river or lake shore), and killed him. This officer lost his badge. In Florida a couple years ago, police shot a tiger that ran out of some bushes. There was no clear indication the tiger was planning to attack. But, the tiger was gunned down. Later, the officer was heard boasting about what he had done, which only enraged the grieving cat owner. Last, but not least, there was the case of a police officer that visited a zoo where a friend of mine was working as a big cat keeper. The officer told this person, without any real provocation to say this, 'If any of those cats ever get out, we will just have to shoot it'. This made my friend (who is himself a firearms expert) very upset that an officer of the law would take a 'kill first and ask questions later' attitude without considering the circumstances.

To sum this all up, what I am trying to say here is that the San Francisco Zoo was not harboring a 'ticking time bomb that could go off any moment' in the form of a very slightly inadequate enclosure design. Furthermore, they were not 'grossly negligent' in having this event happen. Bizarre incidents like this occur in all walks of life, when we least expect them. The zoo should be allowed to make their changes, and get on with life. They do not need to be slapped with all sorts of new rules and sanctions. They do not need the degrading harassment of the animal rights people. Their own internal mechanisms for dealing with disasters should be allowed to function as unimpeded as possible. And, this should serve as a reminder that the 'nut cases' are out there and nothing that can be done will ever be enough to prevent them from sometimes 'succeeding'. So trying to make a '100 percent safe' tiger exhibit would only succeed in making a '100 percent poor tiger exhibit'.
Cut the zoo some slack!

Tim Stoffel can be reached at tim@lionlamb.us  Visit his website for more.

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