Niche - Role and position a species has in the ecosystem and environment
A nice quiche (niche) rolled off the table to take pole position on the starting grid.
The niche occupied by African wild dogs is one of a long-distance running predator. They hunt by chasing their prey over long distances until the prey are worn down to the point they are physically exhausted and can no longer run to avoid the dogs.
Cheetahs live in the same habitat as African wild dogs but the niche they occupy is the one of a fast sprinting predator. Cheetahs are able to run much faster than African wild dogs, but they can only sustain this speed for a few seconds before their bodies overheat and they must give up chasing their prey.
When an organism becomes more specialised to fill a specific niche it reduces the amount of competition it faces.