The forest of Cat Tien National Park is great for reptiles such as snakes, lizards, chameleons,... The forest of Cat Tien is also home to a number of primates including rare and endangered species: lorises, macaques, gibbons, langurs (lutungs, doucs)... Trails in the forest require that the trip be escorted by experienced an wildlife guide. 

And it is advised you have rubber boots, long pants, long-sleeved shirts anytime to venture into forest in Vietnam. Your clothes should have neutral colors or colors which go well with the environment: camouflage, green, olive-green, dark colors...And be armed with insect repellents, anti-leech cream, too. 

The grassland at the national park is wonderful for spotting wild deers, muntjacs, elephants, gaurs, mongooses... It is advised that a wildlife spotting tour at Cat Tien be done by jeep. It is safer in case you encounter gaurs and elephants as these beasts do not see vehicles as threats. You come out of the vehicle in the wild, you may be a target of attack by wild animals as they consider you as a threat.