Answer:
Intraspecific competition examples,
Interspecific competition examples,
and what causes it to happen. Skip to the bottom for shortest answer.
But why does this happen? ↓
This competition happens because of limiting factors in the ecosystem, and general competition. Animals compete for their food because they need this food to survive. If they do not compete for the food, the other animal will get the food and the opposing animal will be left hungry. These are the main reasons why animals will compete for their resources.
In conclusion,
In a short sum, competition happens because animals need food, and when they can't get food, they compete.