Crocodiles will soon hit the headlines of the newspapers again as the temperatures warm and our summer rains begin to fall steadily – that’s if people do not follow a few basic guidelines provided below on how to avoid conflict with this reptile which remains the supreme predator of Africa’s rivers.
Of the 23 species of crocodiles, Africa has 3. The crocodile found in Swaziland is known as the “Nile” crocodile.Crocodiles are highly specialized and patient ambush predators with mottled shades of green, grey and black which makes them almost impossible to detect in the water while they lie in wait for their prey.
In addition to their colour, their streamline shape, webbed feet and positioning of the eyes, ears and nostrils on the top of the head make crocodile’s the ultimate aquatic ambush predator. This enables them to have full senses of their surroundings while their bodies remain well hidden below the water surface.
When potential prey approaches the water, the hunting crocodile will submerge below the water and stealthily sneak up on the unsuspecting prey which could include pigs, cattle, buffalo, and humans. The crocodile will occasionally raise its eyes slightly above the water’s surface to assess its approach before submerging again and moving closer. When the target is in range, the crocodile will suddenly lunge forward in an incredible show of strength and speed, snapping its powerful jaws closed on the closest part of the targeted prey. The victim will then be dragged into deeper water where it is drowned. The carcass (if a large animal) will be stored in the water until it decomposes. This aids the crocodile in tearing the carcass apart by rolling and twisting pieces of the body off before swallowing whole limbs etc., washing it down with water. The bones and horns are then quickly digested by the gastric enzymes (stomach acids) which are the most acidic recorded in any vertebrate animal.
Having mated, the female crocodile will lay 20-95 eggs into a nest in the sand which she will cover and then guard against predators such as monitor lizards and mongooses. After 2½ – 3 months the eggs will hatch. The young crocodiles vary from ± 27 – 37cm long and their sex is determined by the temperatures which they have been exposed to in the nest as hormonal responses to the different temperatures determines the hatchling’s sex. This is a different mechanism to most other animals, where the sex is determined by the combination of X and Y chromosomes at the time of fertilization.
After the female has carried the young hatchlings to the water in her mouth, the hatchlings graduate from preying on small fish, insects and frogs to eventually being able to prey on animals as large as buffalo when they grow over 4 meters long.
It is believed that under natural conditions, approximately only 1-2% of crocodile hatchlings survive to adulthood as they are heavily predated on by fish, monitor lizards, birds, snakes and predatory mammals while they are young.
Crocodiles are reptiles that have inhabited warm waters such as the Lowveld and Middleveld rivers of Swaziland for millions of years.
Crocodiles have lived in more or less their present form for 240 million years, having outlived the dinosaurs.
Crocodiles are listed as Royal Game in Swaziland and are therefore well protected.
In South Africa, crocodiles are listed as a Specially Protected Species.
Being listed in the United Nations Convention on International trade in Endangered Species of Fauna and Flora (CITES) on Appendix I & II, the trade in crocodiles and their products is therefore strictly controlled globally.
• Crocodiles hatch from eggs and grow from 27cm up to 5 meters in length.
• Only become dangerous to humans from +- 2 meters length.
• Up to 2 meters length, they feed on fish, insects, carrion and small animals.
• Need deep water to drown caught prey.
• Large crocodiles in deep water can kill animals as big as cattle and buffalo.
• Crocodiles hunt by ambushing prey, which comes to swim, drink or wallow at the waters edge.
• They lunge forward and grab the prey with their mouths before dragging the struggling victim into deeper water to drown it. Deep water is needed for drowning prey and animals as big as cattle and buffalo are killed in this manner.
• Crocodiles may go onto land to retrieve dead animals or incapacitated animals, but they do not hunt out of the water.
• On land they are likely to bite or swat their tails in self defence if one approaches too closely
• When people come to the waters edge to drink, collect water, fish or swim, they fall into the category of prey for crocodiles.
• Once a crocodile has killed its prey, it places it somewhere in the river or dam and waits for it to decompose.
• Crocodiles have teeth like a rake and therefore cannot cut pieces of meat off a carcass like many other predators but can exert a force of up to 1 ton when they bite.
• Once the meat becomes decomposed, pieces of the carcass are twisted off by rolling in the water.
• Crocodiles are also highly efficient scavengers and eat on any carcass that may float down the river, thus keeping the waters clean.
• For this reason crocodiles are blamed for many more deaths than they are actually responsible for because we automatically assume that because a crocodile is seen guarding a carcass in the river, it was killed by that crocodile.
• In undisturbed systems, crocodiles help to control the populations of predatory barble (cat-fish) which in turn lends to a healthy diversity of other fish species.
• When the weather warms up during the Summer months, the crocodile’s metabolism, (kugayeka kwe kudla emtimbeni kutoze umtimba abe nemandla), speeds up and it therefore needs to feed more often.
• During the cooler months, the metabolism slows down and crocodiles go for months without a meal.
It can therefore safely be said that in Swaziland, due to our temperature variations between Summer and Winter, crocodiles only actively hunt during the warmer months.
However during the cooler months if you swim or enter a crocodile’s territory/habitat you may be caught and killed by the crocodile but it is unlikely to feed.
• Crocodiles also have the habit of looking for new homes and can cover long distances over land during rainy weather and at night.
HOW TO AVOID PROBLEMS WITH CROCODILES
As with drinking and driving using common sense and making behavioral changes are key to avoiding conflict with crocodiles!
Rule # 1: Use your common sense – If you drink and drive you are likely to have an accident– the same applies to swimming in waters likely to contain crocodiles!
Rule # 2: Consider all waters (drains, pools, canals and rivers) to contain crocodiles in the Middleveld and Lowveld. You will never know when a crocodile has moved into a pool.
Rule # 3: If you must go to the waters edge do not spend time in the same place – keep moving aroundand do what you need to do as quickly as possible and retreat. Find a place where the water is too shallow for a crocodile to hide underwater and do what you have to do quickly. In areas where crocodiles are known to occur, barriers (e.g. weld-mesh) can be placed in the water to protect those that are collecting water.
Rule # 4: Do not swim near deep or dirty waters in the Lowveld and Middleveld, you will only be invading the crocodile’s home and tempting him with a potential meal. STOP OTHERS FROM SWIMMING as well.
Rule # 5: Do not splash while in the water. Crocodiles are attracted by splashing as it indicates to him that you are struggling and this offers an easy catch for a crocodile. If you find yourself having to swim, try to do so as quietly as possible. It is a popular belief that a crocodile’s favourite meal is a dog. This is untrue and comes from the fact that dogs splash when they swim and therefore are more attractive to crocodiles. Crocodiles eat a wide variety of meat.
Rule # 6: If you find a crocodile with a carcass in the water, do not try to take it away from it as this will only endanger yourself and will ensure that the crocodile remains hungry and will therefore need to catch something else or somebody else to satisfy its hunger.
Rule # 7: If you do end up being caught by a large crocodile, you have little chance of surviving as crocodiles are tremendously strong and efficient swimmers.
If you have the presence of mind, then try to stop the crocodile from dragging you to deep water and you may try gouging at its eyes to induce the crocodile to release its grip. Generally speaking – your chances of escape from a large crocodile are very slim.
• Remember that crocodiles are protected by law in Swaziland whether inside or outside a Game Reserve.
• It is therefore illegal to take the law into your own hands and kill, capture, keep, hunt or injure a crocodile without a permit.
• The course of action to take with problem animals is as follows:
- Make sure it is a crocodile, which has the ability (size) to endanger livestock and human life, and not a Leguaan (Monitor lizard, Chamu).
- Report the crocodile to Game Rangers at Big Game Parks – 23838100 or 252839434 or your nearest Police Station.
As with drinking and driving, using your common sense and making the appropriate behavioral changes are key to avoiding conflict with crocodiles!