Competition:
* Resource competition: Both species may compete for the same resources like food, water, shelter, or nesting sites. The more similar their needs, the more intense the competition. This can lead to one species outcompeting the other, or to both species adapting to use slightly different resources.
* Interspecific competition: This is competition between different species. The outcome depends on the relative fitness of each species, which can be influenced by factors like:
* Abundance: If one species is more abundant, it may be able to outcompete the other for resources.
* Reproductive rate: A species that reproduces faster may be better able to survive competition.
* Efficiency: A species that is more efficient at obtaining resources may have an advantage.
Coexistence:
* Resource partitioning: Species can evolve to specialize on different resources, reducing competition. For example, different bird species may specialize on different types of insects or use different parts of a tree for nesting.
* Character displacement: Species may evolve differences in physical or behavioral characteristics that minimize competition. This could involve changes in diet, body size, or even mating behaviors.
* Mutualism: In some cases, two species may develop a mutually beneficial relationship, such as a cleaner fish removing parasites from a larger fish.
Predation:
* Predator-prey interactions: One species may become prey for the other. This can lead to population fluctuations as predator and prey populations cycle.
Other possibilities:
* Disease transmission: If the species are closely related, they may be susceptible to the same diseases.
* Hybridization: In some cases, similar species can interbreed, leading to the formation of new hybrid species.
The outcome depends on:
* The degree of similarity: The more similar the species, the greater the potential for competition.
* The abundance of resources: If resources are scarce, competition will be more intense.
* The competitive ability of each species: The species that is more efficient at acquiring resources will be more successful.
* The presence of other factors: Predators, disease, and environmental changes can also influence the outcome.
Examples:
* Lions and leopards: These big cats share habitats in Africa, and often compete for prey. Leopards are smaller and more agile, allowing them to hunt in trees, while lions are larger and more social, allowing them to take down larger prey. This example illustrates resource partitioning.
* Red squirrels and grey squirrels: Grey squirrels are larger and more aggressive, and have outcompeted red squirrels in many areas. This illustrates interspecific competition.
Overall, the interaction between two similar animals sharing a habitat can be complex and dynamic. The outcome depends on the specific species involved and the environmental conditions.