Explanation: Sudden Increase Factors:
- Since there are no predators, there are no ways they could be eaten, with this case, it significantly increases the population.
- Since there are a lot of females, and some males, the males could find mates, and have some baby reindeer, which also increase the population.
Sudden Decrease Factors:
- One decreasing factor is starvation. With there being so many reindeers, all the food is going away quickly. After a few years after the growth spurt, most of them probably died because of there not being a lot of food.
- Another decreasing factor is Old Age. Since there are 21 females, they are older than the babies, and they couldn't have lived much longer, and probably died.
- Another factor; sickness. With there being starvation, their immune system is degrading, and meaning sicknesses could come, so maybe a huge sickness // disease came, and wiped out quite a bit of the population.
I really hoped this helped. :)