A northern pike is a carnivorous fresh-water game fish that lives mainly in North American and European lakes and streams. It is elongated like an eel and captures its prey with its duck-like bill and rows of pointy canine teeth. Its scientific name is Esox lucius. It is also known as a jackfish, pickerel or great northern pike.

A northern pike can grow up to 30 inches (76 cm) and eat up to four times its weight per year. They are known to hunt frogs, other fish and even small mammals or birds. They can be considered a nuisance to commercial salmon and trout farmers who often catch and kill northern pikes to keep them from destroying the fish population in their territories. They also prey on ducklings and may be killed by gamekeepers to preserve the number of ducks for hunting season.

The backs and sides of northern pikes range from olive to brown in color, while their undersides are usually colored white to cream. They also have light spots on their bodies that distinguish them from muskies, similar-looking fish that often share the same habitat. Both fish eat other animals and hide among underwater plants to capture their prey. They also both have similar markings and are drably colored to help them blend into their surroundings. The muskies or muskellunge, however, have the opposite coloring from northern pikes, with dark spots on a lighter colored body.

The northern pike is considered an easy fish to catch because it will readily snap at most bait. Spring is thought to be the best time to fish for northern pike because that is when they move close to the shoreline to spawn. The weeds that normally grow around the shores of rivers and streams in the summer are not plentiful yet and make the northern pike highly visible to their two main predators, humans and lamprey eels.

Northern pike eggs hatch two to three weeks after the mother deposits them at the bottom of the river or stream bed. Female northern pikes can lay up to 50,000 eggs at one time. The newly born fish survive off the yolk of the egg for about 10 days and are then considered fully independent and ready to hunt. Freshly hatched northern pikes are often eaten by other pike and waterfowls. A northern pike that survives to adulthood can live up to 20 years in the wild.