INTRODUCTION
Crocodiles are very difficult and challenging to hunt as they have extremely good eyesight, hearing, and smell, and have an almost uncanny ability to sense potential danger. They are naturally shy and easily alarmed and will immediately take to the water if they detect some threat or are warned by birds that are often found in similar habitat, such as plovers, water dikkop, and sandpipers.
SPECIES DESCRIPTION
Nile crocodiles can grow to a length of 6m (Figure 1) and may exceed 1000kg in weight. The jaws are long and have prominent conical teeth. The eyes and valved nostrils are situated on top of the head. The skin is covered with horny, geometric plates many of which are keeled and bony. The plates on top of the head are fused to the skull. They have five toes on the front feet and four on the rear. The hind feet are partially webbed (Figure 2).
The tail makes up 40% of the total body length and has two raised keels. Crocodiles are excellent swimmers and can catch prey underwater without drowning, as the valves in the nostrils and throat (gular valve) close when opening the mouth underwater. This means that crocodiles cannot swallow prey underwater and must surface for the gular valve to open to allow it to swallow. External ear openings also have flaps that close when the crocodile submerges. The upper jaw is an extension of the skull, and only the lower jaw can be moved (Figure 3).
On hot days when a crocodile is basking in the sun with its mouth open to lose heat by evaporation, it has to hold its head upwards, allowing the lower jaw to fall open and rest on the ground. During cold mornings and late afternoons, crocodiles allow the sun to shine directly into their mouths. Heat is taken up by the soft membrane in the mouth and is dispersed throughout the blood circulation to raise body temperature. Crocodiles have a four-chambered heart with complete division of the ventricles, permitting more efficient blood oxygenation.
They have an extra eyelid, called the nictitating membrane, which sweeps dirt from the eyeball. They have well-developed legs that permit a “high walk” and even enable them to gallop at a fast pace. There is a hard palate in the roof of the mouth and a valve which closes the throat to prevent water inhalation when the crocodile is underwater. They have a longitudinal cloacal aperture. Crocodiles have more than 60 teeth designed for gripping and interlocking when the jaws are closed, exposing the fourth mandibular tooth (it his hidden in a socket in alligators).
BEHAVIOUR AND HABITS
The diet of crocodiles varies according to their size. Hatchlings feed mainly on frogs, insects, snails, and small crabs. Once they reach about a meter in length, crocodiles feed mainly on fish. Crocodiles of three meters and bigger feed on birds, fish, terrapins, snakes, otters, warthogs, other crocodiles, small to medium-sized antelopes, and man.
Big crocodiles may even take species as large as zebras and buffalo. Larger prey is dragged into water and drowned. If prey is too large to be swallowed whole, bits are torn off by seizing a mouthful and spinning along the long axis. Cooperative behaviour in feeding and breaking up of prey has been observed. Crocodiles will readily feed on carrion.
Breeding
Sexually mature at 12 – 15 years (2-3 meters). Dominance hierarchy is established between males at the beginning of the breeding season (May). Mating occurs mostly between July – August. Crocodiles are surprisingly attentive parents, and nest construction and care of the young are very advanced. Anything between 16-80 white, hard-shelled eggs are laid in a nest excavated by the female on a suitable sand bank in October – November at a depth of 30 – 40 cm (Figure 4).
The female protects eggs during incubation and does not eat at this time, going to water only to drink. The nest site is defended against predators. The greatest threat to the eggs comes from the Nile monitor and other crocodiles. Eggs hatch after 84 – 90 days. The sex of hatchlings is determined by the incubation temperature in the nest. Female crocodiles develop when the incubation temperature is between 26-300C and males when the temperature is between 31-340C.
Their cheeping noise stimulates the female to open the nest. She carries the young to water. There is a very high mortality in hatchlings rate with only one crocodile out of a nest of 50 eggs surviving to maturity. Large wild crocodiles may live between 60-100 years.
Crocodiles can be very dangerous (Figure 5). Hunters and guides must take care around water bodies where crocodiles are present (Figure 6). Don’t allow clients to approach too close to the edge of the water, as crocodiles can lie in wait and seize prey on the riverbanks. Keep at least three to four meters away from the edge. Under no circumstances should hunters allow clients to swim in water where crocodiles are present.
If it is necessary to collect water for some other reason, look for a rocky place where water is very shallow – no more than 10cm deep. Crocodiles may also be encountered on land. Keep a safe distance from them and don’t get between them and water as they, in all likelihood, will try and head back to water and may attack if you get in the way. Keep a good eye open for signs of crocs in water and on land where they often lie and bask in the sun.
SIGNS AND TRACKING
Tracks
Crocodiles have distinctive tracks that will be found alongside and close to bodies of water. The smaller front foot has 5 toes, and the larger (partially webbed) rear track has 4 toes. Their tails also leave characteristic drag marks when they walk around on land (Figure 7). Body imprints can be found where they lie and bask on sandbanks.
Scat
Crocodile scat is greyish when fresh and becomes whiter as it ages. It has a pasty consistency (Figure 8).
Vocalizing
Crocodiles can make hissing and roaring sounds.
Nests
During mating season, crocodiles will dig holes in which eggs will be laid to incubate. There will be a lot of tracks and tail drags leading to and from nesting sites. Crocodiles are very protective of their nests.
HUNTING METHODS
Because crocs have such acute senses, it is really difficult to stalk up close enough for a shot, and more success can be achieved by ambushing a known basking site or a baited position. A hunter would have to recce along a river to locate preferred basking sites and then set up a hide or find a well-concealed spot from where he would wait silently and patiently for crocs to exit the water and start basking in the warm sun.
When using bait to lure crocodiles to within shooting range, secure the bait in the water, right at the water’s edge; otherwise, it will be carried off by hyenas and other scavengers. Any form of meat can be used as bait. Crocs are not fussy eaters. Build a blind at the same time as you place the bait so as not to cause repeated disturbance. A sandbag or shooting stick should be used, and shots taken from the prone – most stable – position.
Determine the exact range from your shooting position to the bait or where you expect the croc to lie so that you can sight the rifle/scope in for this precise distance. After having fed on the bait, a crocodile will often lie next to the bait to protect it from other crocs and will afford the hunter a decent shot proposition.
Precise first shot placement is required to anchor a crocodile. Miss the brain by an inch, and the croc will be in the water and gone before you have time to get a second shot. The average range in crocodile hunting where the hunter will be expected to hit a golf-sized target with his chosen rifle/scope/bullet combination using some form of dead-rest (sandbag or shooting stick) is about 70m (Figure 9).
RECOMMENDED CALIBRES AND BOWHUNTING EQUIPMENT
Suitable calibres
Whereas smaller crocs can be taken with the various 7mm calibres using 170 grain softpoint bullets or .30 calibre rifles (.303, .308 Win., .30-06, etc.) using 180 grain bullets, for big crocodiles these should be considered marginal (Figure 10).
The skull of a big crocodile is comprised of extremely hard bone and covered with tough skin, and top-quality soft points are required for all crocodile headshots.
Better options include .338 or .35 calibre cartridges using 250 grain premium quality soft point bullets or .375 H&H using 300 grain core-bonded soft point bullets.
A 4-power scope or 1.5-5x variable scope is necessary for precise shooting.
Bows and arrows
It is possible to hunt crocodiles from a hide with archery equipment. Use a 70 – 80-pound draw-weight bow and a heavy arrow to make sure you get an arrow through the lungs (Figure 11).
SHOT PLACEMENT
Only two shots will anchor a big crocodile. The brain shot or the high (neck) spinal shot (Figure 12). The small brain lies midway between the eyes and ear ridges, about 50mm below eye level.
If the croc is anchored with your first shot, give it two more shots with solids – one in the shoulder and one in the hip to prevent it from standing up or moving off.
Crocodiles are notoriously difficult to kill and may still squirm about or move their tails hours after being shot. A veterinarian dissected the heart out of a crocodile 5 hours after it had been shot, and the heart was still beating.
Only heart/lung shots should be attempted with archery equipment. If shot through the lungs crocodile will usually leave the water to stop drowning and will expire (in time) on land.
TROPHY MEASUREMENT AND PHOTOS
See Figures 13 and 14.
REFERENCES
- Branch, B. (1988). Field guide to the snakes and other reptiles of Southern Africa. Struik Publishers. Cape Town. South Africa.
- Cheney, C.S. (2013). The Comprehensive Guide to Tracking – Safari Press
- Mellon, L. (1975) African Hunter –Harcourt Brace Jovanovich New York and London
- Robertson, K. (1999). The Perfect Shot – Safari Press
- Robertson, K (2007). Africa’s Most Dangerous – Safari Press
