From Jay:
cPrey values are just the IDs of the animals, staff, and guests. Offhand, I do not know if there is a list of these IDs. Here is a list based on ZT's ".dll" files, but a few of these are not used. Some of the in-game animals have cPrey values in the range of 5302 to 5324. Those are numbers that were never assigned to an animal.
5000, "African Elephant"
5001, "Giant Panda"
5002, "Polar Bear"
5003, "Chimpanzee"
5004, "Plains Zebra"
5005, "Thomson’s Gazelle"
5006, "Lion"
5007, "Bengal Tiger"
5008, "Siberian Tiger"
5009, "Cheetah"
5010, "Leopard"
5011, "Black Leopard"
5012, "Snow Leopard"
5013, "Clouded Leopard"
5014, "Jaguar"
5015, "Gray Wolf"
5016, "Grizzly Bear"
5017, "Black Bear"
5018, "Spotted Hyena"
5019, "Olive Baboon"
5020, "Mandrill"
5021, "Lowland Gorilla"
5022, "Orangutan"
5023, "Red Kangaroo"
5024, "Black Rhinoceros"
5025, "Common Wildebeest"
5026, "American Bison"
5027, "Ibex"
5028, "Okapi"
5029, "Moose"
5030, "African Buffalo"
5031, "Gemsbok"
5032, "American Bighorn Sheep"
5033, "Giraffe"
5034, "Dromedary Camel"
5035, "Hippopotamus"
5036, "Markhor"
5037, "Greater Flamingo"
5038, "Ostrich"
5039, "Emperor Penguin"
5040, "California Sea Lion"
5041, "Saltwater Crocodile"
5042, "Giant Anteater"
5043, "African Warthog"
5044, "Mother Chimpanzee"
5045, "White Bengal Tiger"
5046, "Triceratops"
5047, "Yeti"
5048, "Arctic Wolf"
5049, "Unicorn"
5076, "Blackbuck"
5077, "Bongo"
5078, "Mountain Lion"
5079, "Sable Antelope"
5080, "Asian Black Bear"
5081, "Asian Elephant"
5085, "Tyrannosaurus rex"
5086, "Saber-toothed Cat"
5087, "Ankylosaurus"
5088, "Gallimimus"
5089, "Iguanodon"
5090, "Lambeosaurus"
5091, "Spinosaurus"
5092, "Styracosaurus"
5093, "Velociraptor"
5094, "Allosaurus"
5095, "Camptosaurus"
5096, "Caudipteryx"
5097, "Kentrosaurus"
5098, "Plesiosaurus"
5099, "Stegosaurus"
5300, "Reindeer"
5301, "Llama"
5325, "Apatosaurus"
5326, "Coelophysis"
5327, "Herrerasaurus"
5328, "Plateosaurus"
5329, "Wooly Mammoth"
5330, "Wooly Rhino"
5331, "Giant Tortoise"
5332, "Deinosuchus"
5340, "Magnet"
5400, "Orca"
5401, "Great White Shark"
5402, "Bottlenose Dolphin"
5403, "Lion's Mane Jelly"
5404, "Elephant Seal"
5405, "Humpback Whale"
5406, "Sperm Whale"
5407, "Narwhal"
5408, "Harbor Porpoise"
5409, "Hammerhead Shark"
5410, "Tiger Shark"
5411, "Shortfin Mako Shark"
5412, "Green Moray Eel"
5413, "Beluga"
5414, "Southern Sea Otter"
5415, "Pacific Octopus"
5416, "West Indian Manatee"
5417, "Pacific Walrus"
5418, "Manta Ray"
5419, "Green Sea Turtle"
5420, "Atlantic Swordfish"
5421, "Giant Squid"
5422, "Bluefin Tuna"
5423, "Great Barracuda"
5424, "Mermaid"
5500, "African Wild Dog"
5501, "Giant Ground Sloth"
5502, "Llama"
5503, "Komodo Dragon"
5504, "Whale Shark"
5505, "Macrauchenia"
5506, "Orangutan"
5507, "Malaysian Tapir"
5508, "Japanese Serow"
5509, "Przewalski's Wild Horse"
5510, "Common Sawfish"
5511, "Javan Rhinoceros"
5514, "Bigfoot"
5515, "Loch Ness Monster"
5516, "Mexican Gray Wolf"
5517, "Bowhead Whale"
9500, "Zookeeper"
9501, "Maintenance Worker"
9502, "Tour Guide"
9503, "Man"
9504, "Woman"
9505, "Boy"
9506, "Girl"
9551, "Scientist"
9552, "Marine Specialist"
There is a cChaseAnimalChance setting that says how often ZT should check if there is prey. But except when that is set to 0, it does not take too long before ZT eventually checks if there is prey. Catching of prey depends on the relative speed of the animals and how many predators there are. If there is only 1 predator, I have seen cases where the prey was too fast to be caught, but that is rare.
I never tested it. I assume it is random which catches which, influenced by their cChaseAnimalChance settings.