The population went down over the years because hunters and diseases might have killed them off. Natural Selection is a big part of the population the Goats that breed and have good genetics will pass down there traits to the younger generation. The mountain goats started dying of because diseases and they have predators that hunt them. The traits that are passed down would be there quickness and strength to run away or fight predators. The strong goats survive. The males fight for breeding right sometimes the strongest get beat and the runner up has a chance to put genetics in the herd. They live in packs up to 50 so he has a lot of work to do. If he breeds 50 females they will have 50 babies or more if they have twins that would be 100. The traits that are passed down are so important because that male or female have survived the elements and there babies will be even more ready. With population the Mountain Goats might not come back from the decrease. They will have to breed rapidly in order to survive the elements and predators. By the time at this rate they will be very endangered. Since they live in the mountain and they are adventurous sometimes they can fall off cliffs and die. By the looks of the graph it looks likes they are going to do extinct. Natural causes kill a lot of the goats like diseases. The strong goats don't get the diseases and they are smart so they don't die of natural causes. Natural Selection is a huge part of the survival of a species. Thank You For Looking at my Website. This Data on the graph is not true the Mountain Goat Population is getting up there so yeah. This was for a class project don't believe this graph. The photos on the bottom of the page show some ways they can die.