Females deposit up to 100,000 eggs at random. The adhesive eggs stick to flooded vegetation for about two weeks before hatching. Northern pike fry feed on plankton and then invertebrates but soon switch to a diet consisting largely of fish. Built for quick acceleration, they ambush prey from cover, seizing fish with needlelike teeth. Indeed, they often swallow fish a third their own length.
Common foods are yellow perch, tullibee, suckers, minnows and other northern pike.
Though northern pike eat sunfish and bass, they prefer more cylindrical fish. Northern pike also eat leeches, frogs and crayfish. Small northern pike remain in shallow weedy water through much of the year. Large northern pike move deeper as summer progresses, seeking oxygenated water of 65 degrees or cooler. Large northern pike become lethargic in warm water, eating little and sometimes losing weight.