The Delaware River Basin has a very diverse ecosystem with a wide variety of wildlife. Eagles, bears, snakes, insects, beavers, otters, herons, Canadian geese, fish, eels, deer, and other animals can be found along the river banks.

Yes, there is a thriving and significant population of American Black Bears along the Delaware River, particularly in the northern reaches where the river borders Pennsylvania, New Jersey, and New York. The Delaware Water Gap National Recreation Area is a major hotspot for bear activity due to its dense forests and abundant food sources. In 2026, wildlife officials estimate that thousands of black bears inhabit the ridges overlooking the river. While the state of Delaware itself technically has a resident bear population of zero, the river basin just to the north in Sussex County, NJ, and Pike County, PA, is one of the most bear-dense regions in the Eastern US. Hikers and campers in these areas are strictly required to use "bear-proof" food storage and maintain a safe distance. Seeing a bear swimming across the river or foraging near the banks is a common occurrence for boaters, though these animals are generally shy and will retreat if they sense human presence, provided they haven't been "habituated" to human food.