The Velociraptors are the primary foe which Anne must contend with. Raptors are the most frequently encountered dinosaur throughout the game's eight levels and demo, making them the main antagonists of the game (Jurassic Park: Trespasser).
"Velociraptor. A small theropod native to China and Mongolia. Pack-hunter. Quite vicious and quite intelligent". The fossil record shows raptors living like wolves or lions, hunting in groups. Ours did the same, perhaps a genetically coded social trait."
"The raptor took shape inside its egg and I watched it on the ultrasound monitor. It looked like a ghost, or a puff of smoke."
"We released the first raptor on April 22nd, 1985. It wandered back and forth near the wall for four minutes and twenty-two seconds before hearing a noise, which drew it further off into the brush."
"The raptor preened itself, utterly confident of its right to be there. Absolutely no consciousness, that it was not the sovereign ruler of this earth."
"In the jungle, the forest and the mountain, three raptor tribes staked out territory. Albertosaurs and the seven T. rex chose their dominions. Uneasy borders drawn around forests, ridges and ponds."
Several different Velociraptor models are known to exist.
Two distinctive models were shown in press released screenshots. These models never made it into the final game, and their functionability is often questioned.
This is the most common raptor featured in prereleased screenshots. Careful observation reveals that the raptor's pose is the same in each picture. This has led to the conclusion that the screenshots containing this raptor are not from the actual game, but renders taken in MAX.
This raptor made its appearance after the previous one. It's position seems more natural compared to the previous, but one screenshot in particular may have been staged: the Raptor is shown brandishing its teeth while perched ontop of the Jungle Canyon crane, and it could only have gotten there if it had jumped the distance (which raptors aren't programmed to do).
The original Velociraptors come in four varieties: Tribe-A, Tribe-B, Tribe-C, and the final Utahraptor (also called the Alpha Raptor). It is possible that each tribe represents a Velociraptor subspecies, or a different genetic version of a single DNA source. This could explain why the tribes encountered earlier in the game are easier to defeat than the later tribes, which may have fewer genetic defects. According to Hammond, the animals grew vicious in captivity; not eating, pacing their cages, growing quick-tempered... they had no choice but to release them into the wild.
The first tribe of raptors that are encountered. They can be found in levels 1-3 and are last seen in The Town (level 4). These have a light orange skin tone, similar to the one that was portrayed in the re-released screenshots. They attack the player by simply charging right towards them, so they are the easiest raptors to defeat since they remain at the same angle when they attack. They are based on the male Velociraptors seen in The Lost World: Jurassic Park.
This raptor seems to have staked its terrain around the center of the island and can be found halfway through level 3, throughout levels of 4, 5, and the beginning of 6. Red spots dominate this species' skin. These raptors attack by running at the player from an angle and then circling from the side until they finally try to kill the player. They appear to be based on the description of the The Lost World novel Velociraptors.
"A third tribe of Raptors took the mountain for their territory. A leaner, tougher breed. Quick, living on birds and tiny lizards."
This raptor appears more yellowish than the other two. This tribe has chosen the mountainous region on and around Mt. Watson as its dominion. It is found halfway through level 6, 7, and in The Summit (level 8).
Tribe C Alpha
"For four months we monitored it, while it preyed on herds in the southern forest...We never knew why it grew so large..."
This is the Alpha Velociraptor (or Utahraptor) of the third raptor tribe. The player fights this raptor only once throughout at the game at the summit. Far larger than the usual velociraptor and almost as big as an Albertosaurus, this is the boss of the game (surprisingly, it was weaker than the former; making it an "anti-climactic boss"). It is mentioned in John Hammond's memoir that in 1988, they captured it for observation, with a kind of "Dinosaur Rodeo" occurring.
Behind the scenes
The Tribe B raptors coloration seems to be based on Steve Kirk Utahraptor design in the book Dinosaur Worlds by Don lessem.
In the game, raptors cannot enter buildings unlike what's mentioned on back of the game box (thanks to the game's rushed development). According to the game manual, it states, "Despite the raptor's intelligence, they cannot 'learn' to open doors." This is a great way to avoid them, especially/mostly useful in The Town.
Raptors aren't programmed to jump, but when playing the game using ATX patch, the raptors can jump. The player can also set raptors to enter buildings through the ATX patch's INI file.
The raptors in the game appear to be cannibalistic; they will eat anything, even fallen comrades (like in the second novel).