My first close contact with the beasts came after I went to Ethiopia in 1967 to take on the job of establishing a new national park in the cliff-rimmed northern mountains.

After a frustrating time in the capital, Addis Ababa, trying to finalize preparations for the trip, John Blower, chief warden of all the country's national parks, decided to send me to the Awash National Park first. There, I was to see how Peter Hay, the warden, had coped with his job of setting up Ethiopia's first national park.

Before going to Ethiopia I had been on Baffin Island in the Canadian Arctic for six months, carrying out a seal survey with the Inuit. Then, less than a month after that, I was in Africa, going out on patrol carrying a loaded semiautomatic carbine, confronting Danakil tribesmen, and trying to be on equal terms with a man who was famous for running off alone in the bush with a knife, a rifle, and just three rounds of ammunition to chase down a rogue lion.

In the Awash National Park there are several hot springs and pools in the foothills of the dormant volcano Mount Fantale. On one patrol with Peter Hay and his rangers, we stopped at a very large hot-spring pool for a bath. Peter stripped off, then took the belt from his shorts, together with a hunting knife in its sheath, and tightened it around his bare midrift. When I looked at this rather strange sight, he nodded to the far bank, where there were several old logs strewn along the shore.

"Just in case one of those buggers tries to get too friendly," he said.

Looking more closely, I saw that the 'logs' were, in fact, crocodiles.

As a little lad in Britain, religiously attending the Saturday-morning "pictures," Tarzan had definitely been my favorite film character, and I especially enjoyed the scenes of him wrestling with crocodiles, Now, however, although I tried to be blase about strapping my own knife and belt around my waist, my nether regions became very tight and shriveled despite the warm water, and I made mine as short a swim as dignity would permit.

It didn't help, mind you, that I had also seen a postcard on sale in Addis Ababa showing a dead crocodile on a river bank, its belly slit open, with the remains of a chewed and half-digested white male lying beside it. Yuck.

Both that croc and those at the hot-spring pool were the notorious African crocodile, Crocodylus niloticus (literally, "lizard of the Nile"), a creature that kills more people than all other large animals combined on the African continent. Until hunters with rifles came along, these fearsome reptiles ranged from the Mediterranean down to South Africa.

However, the largest of all the crocodilians is the estuarine, or saltwater crocodile, of the coastal regions of southern Asia and northern Australia. This one, Crocodylus porosus, can reach more than 5 meters in length.

Here I'd like to discuss the difference between a crocodile and an alligator. Put simply, the head of an alligator is more rounded than a crocodile's and its skin is more lumpy. When its jaws are shut, most of the teeth are hidden, whereas crocodiles have a permanent jagged grin that looks positively evil. Also, I met a crocodile expert who said that if a man was in the same area with a crocodile and an alligator, then both he and the alligator would have to watch out because the crocodile would want to kill and eat them both.

Alligator skins were first used to make boots on a large scale for the troops fighting in the American Civil War (1861-65). Thereafter, both crocodile and alligator skins became fashionable for shoes, boots, handbags and suchlike.

There is an American crocodile, Crocodylus acutus, but it is very rare, with perhaps as few as 20 breeding females in Florida. It was once abundant in Mexico, the Caribbean islands and Dominica. Excessive hunting decimated its numbers, whereas the American alligator has been very well protected and studied. Cuba also has several large crocodile farms, raising their own species, Crocodylus rhombifer.

Recently -- as you may have read in this column last month -- I was on a Japanese cruise ship that stopped in Darwin, capital of Australia's Northern Territory. Desperately in need of a large, juicy steak (instead of the expensive, flaccid, fatty, pathetically poor excuse for beef that is so popular in Japan), and curious to see a wild saltwater crocodile, I took a break from novel-writing and went ashore.

Steak and Kilkenny draught beer first, then off to find a tour operator who would take me to the very muddy Adelaide River where I'd read that there were plenty of wild crocodiles.

Although we didn't see any really huge ones, the creatures were impressive, especially a big old fellow who had lost two legs in combat with other crocs.

The two guides had an impressive knowledge of the biology and the history of crocodiles and kept us entertained as we slowly cruised the river. Among the fascinating facts and anecdotes they told us, the following are the ones I recall:

* Crocodiles evolved with the dinosaurs, but survived when the great land lizards were wiped out;

* The crocodile is a caring mother, sitting on her nest until the young hatch, then carrying them down to the water in her mouth and guarding them for two months;

* Crocodiles can convert 30 percent of their food into body mass, compared with about 3 percent for humans;

* A crocodile's normal heart rate is 15 to 39 beats per minute, but this drops to one to three beats every three minutes when resting underwater;

* Crocodiles have seasonal layers in their bones, like tree rings, and live to about 80 years;

* Crocodiles' teeth are offset, like shears, and, like sharks, they can grow new ones;

* Crocodiles have a fantastic immune system and are unusually resilient to radiation;

* They are the world's largest nonoceanic predators.

And so on, all delivered in Australian accents so strong they were poetic.

All this was happening in a double-decker boat, with one man driving and a lady dangling slabs of meat swinging on a rope attached to a long pole. When a crocodile was sighted, she swung and bobbed the meat over the water to persuade the creature to jump. While this certainly was the easiest way for tourists like me to get a good look and a photograph, I felt a bit uneasy about these animals getting so used to an easy snack and boats full of people. Would they not associate humans with food? Most wildlife experts would decry this practice, but in northern Australia nobody seemed to be bothered.

Also, even though the upper deck was high enough above the water to be safe, and the lower deck was glassed in, looking through the glass at the big, yellow, reptilian eyes and those awful jagged teeth made me wonder what would happen if a really big croc decided to lunge through the thin glass and grab itself a larger treat than the little chunks of meat being dangled outside.

We, at least, lived to tell the tale, and before going back to the cruise ship we went for a meal in Darwin at a restaurant called The Magic Wok. There they served a tremendous variety of vegetables, mushrooms, seafood and meats, which you select yourself and then have cooked in Chinese style. I chose cuts of buffalo, kangaroo, emu and crocodile for my meat dishes, and all were good. Crocodile meat, I discovered, is close to the color of chicken, and to me tastes like a cross between frog and chicken.

Stir-fried with vegetables and red peppers in a wok is the closest I ever want to get to a crocodile, thank you very much.