You have to round up the spotted goat that the chupacabra likes and get them to run to the weird skull thing. The farmer who lent you the jeep says he will come help you. After that go to the skull...
The first sample of fur is just wild dog fur so to find the real thing first you get the jeep from the guy in town at Puerto Rico next you drive to all the farms and talk to the farmers once you do...
You fly to Puerto Rico in the helicopter you talk to the farmer and click I'm not afraid and he'll lend you his truck and he tells you to deliver some seeds to his brother you find your way there you...