Tarantulas are extremely common in some areas. I have personally seen hundreds in the cane fields. While their bite is toxic, it is not dangerous to an adult. What is hazardous is the invisible cloud of poisonous body hairs that they release by scratching their lower back. These "urticating" hairs blind attacking birds, which fall to the ground and are then bitten and killed by the tarantulas. For this reason avoid close contact. Centipedes are virulent Their sting is extremely painful, but you will rarely see them unless you are digging in your garden. Snakes are uncommon and not poisonous. Mosquitos and biting midges are common but can be combatted by using insect repellent containing "deet". Their itchy bites are best fixed with a weak solution of ammonia, or by meat tenderizer. While SCUBA diving or snorkelling avoid touching anything. Sea urchin spines are poisonous and difficult to remove. Only dive with an experiensed divemaster. You will probably never encounter any of the things I ha ve described, so have a great holiday!!! Canadian Bob.