Cuckoo and Warbler: A cuckoo may lay its eggs in a warbler’s nest. The cuckoo’s young will displace the warbler’s young, and the warbler will raise the cuckoo’s young.

Hermit Crabs and Snails: Hermit crabs live in shells made and then abandoned by snails.

Golden Jackals and Tigers: If a golden jackal is expelled from its pack, it may follow a tiger, trailing it at a safe distance and then feeding on the tiger’s leftover kills.

Wrasse Fish & Black Sea Bass: Wrasse fish eat the parasites found on the black sea bass’s body.

Alligator and Deer: A lucky alligator spots a deer drinking water, attacks the deer, kills it and eats it for food.

Bed Bugs and Human: Bed bugs will bite and feed off a human up to 500 times in one night. This causes small red bumps and itchiness to the human.

Bison and Cowbird: As bison walk through the grass, insects become active and are seen and eaten by the cowbird.

Goat and Grass: A goat munches on the grass in a field for its food.

Hermit Crab and Anemones: The crab attaches anemones to its shell using them as camouflage and as a deterrent to potential predators. The anemones have a “mobile home” and get more exposure to food than if they remained stationary.

Algae and Fungi (Lichen): Algae and fungi can live together, forming lichen. The algae produce carbohydrates through photosynthesis, providing nutrients to both the algae and the fungi. The fungi provide moisture for the algae.

Bear and Berries: The bear forages through the forest and finds berries for food.

Mistletoe and Oak Tree: Mistletoe extracts water and nutrients from the oak tree, causing harm to the oak tree.

Lion and Zebra: The lion hunts and kills the zebra for its food.

Mosses and Trees: Mosses can grow on the trunks or branches of trees. They get light they need as well as nutrients that run down along the trees. The mosses do not affect the trees.

Otters and Kelp: Otters float and sleep on forests of kelp in the water. The kelp provides them a place to anchor in the moving water. The otters eat sea urchins, which normally feed on the kelp.

Deer and Tick: Ticks feed on deer blood, causing irritation to the deer and potentially giving it various such as Lyme disease.

Frog and Insect: The frog uses its long, sticky tongue to catch insects for food.

Goby fish and Sea Urchins: The goby fish live amongst the sea urchins and are given protection from predators.