Atlantic Bottlenose Dolphin are seen at Assateague as they jump out of the waves while riding the surf. Two types of bottlenose dolphin exist, the offshore and coastal form. The offshore bottlenose dolphins are found in larger groups than the coastal ones. They seem to be migratory, although some stay in an area year-round while others travel up and down the coast.

Atlantic Bottlenose Dolphins can grow to 12 feet in length and weight 1,400 pounds. Other Bottlenose Dolphins are 8-10 feet long and weigh 400-500 pounds at maturity. Males are slightly larger than females. The males reach sexual maturity at 10-12 years of age, females at 5-12 years. Females bear a single calf every 2 or 3 years. Calves spend up to five years with their mothers while learning to capture food and live with other dolphins. Dolphins are often seen herding fish while they hunt as a group. A dolphin has a life span of approx. 25 years but some have been known to live into their late 40s.