Croc Attack

Crocodile attacks in South Africa and Swaziland, 1984-2014

Why are attacks seasonal?

Crocodile attacks are very seasonal, with most happening from October to March. June and July are free of attacks so far. We are very interested to discover why this is so.

There are three main explanations for this seasonality of attacks:

  1. Crocodiles are cold-blooded (ectothermic) and more active and hungry when it is hot (inactive when it is cold).
  2. When water levels are high (wet season) crocodiles move around more and there are more chances of meeting one.
  3. Crocodiles are aggressive in the breeding season (warm, wet season).

It may be a combination of all three – but none of these explanations has been proven. This is why we are gathering long-term data on temperature, rainfall and water levels for attack events. We want to try to find out which are most important for explaining when and why most attacks happen. We must remember that climatic conditions also influence what humans are doing at different times of the year (e.g. swimming or fishing).

We have decided on what is hot or cool season according to minimum temperatures. This is because, so far, minimum temperature data gives us the best explanation of attack seasonality. More than 90% of attacks occur during periods when minimum temperatures are above 15°C. So far, there is no clear sign that either rainfall or water levels are mostly above, or below, average when attacks occur.

Does size matter?

Although in the wild there will be more small crocs than medium or large ones, young crocs eat mostly small creatures like insects and frogs, moving on to fish as they grow. Most bites by small crocs will be mistakes or defensive. Medium-sized crocs can catch animals, and large crocs can easily catch large mammals, including ourselves. We are curious to discover if more attacks are by medium-sized or large crocs, and whether more attacks by large crocs are fatal. However, because it is hard to guess a crocodile's length, we accept only actual measurements, or estimates by experienced people. We need more accurate measurements!

Limits of our knowledge

Calculating risk requires knowing a lot of things. Ideally, we need to know what people are doing in the water when they are attacked, as well as when they are not. We need to know what people and crocs are doing in the water, when and why. For now, we know most about the ‘hits’ (attacks) and less about the ‘misses’. We know about what has happened when croc attacks did occur. It is important to remember that not all attacks are reported, and sometimes we have only a few details about the attack. Our summary is based on what has been reported. You can help us by sending us more information on croc attacks in your area.

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