Cannibalism is certainly an uncommon behavior, but it can occur in several animal species under certain circumstances. Here are seven situations in which animals have exhibited cannibalistic behavior:

1. **Carnivorous Mammals:** Some species of carnivorous mammals, such as lions and bears, can become cannibals in extreme situations, such as food shortages or competition for territory.

2. **Insects:** Many species of insects, such as some ants and crickets, can exhibit cannibalistic behavior, especially when confined to small spaces or when food is scarce.

3. **Fish:** Some fish, such as salmon, may feed on conspecifics under certain conditions, such as when they are stressed, sick, or in very high population densities.

4. **Spiders:** Some species of spiders, such as the black widow, are known to exhibit cannibalism, where the female may eat the male after mating.

5. **Reptiles:** Certain reptiles, such as snakes and turtles, can exhibit cannibalistic behavior, especially when they are competing for scarce resources.

6. **Birds:** Although less common, cannibalism can also occur among birds, as in some species of seabirds when parents feed on their own young.

7. **Primates:** In extreme cases of stress or food shortages, some primates, such as chimpanzees and gorillas, have been documented exhibiting cannibalistic behavior, although it is very rare.

These are just a few examples of situations in which animals may resort to cannibalism, usually as a desperate strategy to survive in adverse conditions.