Why does the population of some animals decrease in number?

Answer 1

There are probably several reasons for this.
1. over hunting. There are many cases where animals have been hunted to extinction--the dodo for one. Whales were well on the way until the whaling ban.
2. loss of habitat. For example, if an animal has a very small specialized environment such as a bog in New York and that bog is drained for a housing development then the animal is doomed.
3. change in climate. North Africa in the past received much more rain then it now does. That has led to extinctions of quite a few species.
4. natural disasters. The large space rock did away with 90% of life on the Earth on several occassions.
5. small unsustainable population. cheetahs and California condors fall into that classification.
6. too specialize food requirements. some animals will eat only one thing. If their food supply disappears, they do also.

Answer 2

Natural progress. Some decrease, some increase.

Answer 3

Over harvesting by hunters or poachers. Which also leads to a higher number of predators to prey. I'm a hunter but think animals need to be harvested in a proper proportion

Answer 4

Maybe some of these species flew off to outer space in UFOs?

Answer 5

Because we as humans have destroyed their habitats, food supply and culled them off for food, pelts, pets, ivory, or our sick simple enjoyment.

It is our fault.

Answer 6

due to reckless killing of such animals for the benefit of human

Answer 7

people are selfish

Answer 8

UUUH they die ???

:o)