Winter is a great time to try and see pods of dolphins within the Monterey Bay in Coastal California. The bottlenose dolphins are year-round residents, but there are also Pacific white-sided dolphins, Risso’s dolphins, and northern right whale dolphins who are winter-only-residents and follow whatever schools of anchovies or squid are present in the bay.
Dolphins are actually a type of whale. Whales, dolphins and porpoises are divided into two groups of whales: toothed and baleen. Dolphins, along with porpoises, sperm whales and orcas are toothed whales that use sharp, pointed teeth to catch fish and other large prey. The name dolphin originates from the Greek delphus or “womb,” and likely meant a “fish with a womb.”
Bottlenose Dolphins: Long-term Residents of Monterey Bay
Bottlenose dolphins (Tursiops truncatus) range all over the world’s oceans in warm or temperate waters. They are found in both shallow coastal water and the open ocean, with special adaptations for each environment. The coastal dolphins have smaller bodies and larger flippers for greater maneuverability. They are 8-9 ft long and about 400 to 550 pounds when fully grown. In contrast, the ones that live offshore in the open ocean are generally about 12 ft long and 1000 lbs. Males tend to be longer and heavier than females. These dolphins have up to 98 cone-shaped teeth, which are used for grasping pray, not for chewing.
Bottlenose dolphins were first observed in Monterey Bay in the early 1980s but have become year-round residents with several pods that stay in the bay and don’t migrate. They can usually be seen just beyond the breaking waves, within half a mile of shore.
Look for bottlenose dolphins in pods of two to maybe a dozen or more swimming through the kelp forest and occasionally stopping and foraging. They have a blue-gray torpedo shaped body with a sickle shaped dorsal fin and a nose that looks like a bottle. Their underside is almost white and this makes them hard to see in the water, both from above and below. Their color may appear silvery or almost black, depending on the lighting. Although some dolphins migrate with the seasons, our local dolphins stay within the Bay.
Bottlenose, like all dolphins, porpoises, and whales, use echo location to navigate, communicate, hunt, and avoid predators. They produce a wide variety of clicks, whistles, moans, squeaks, and other sounds with their nose and structures that protrude in their nasal passages. They send the sound out using a special dome, called a “melon,” on their forehead and receive the echoes in oil-filled jawbones, that send the nerve impulse to the brain.
They can be very friendly and interact with swimmers and divers and are famous for riding on the bow waves of boats and even occasionally come into the breakers close to shore to body surf waves. Caution is always prudent however, as they can also be very aggressive and possibly dangerous, especially during the mating season.
Timing of reproduction varies in different parts of the world. Along the Pacific Coast, adult male dolphins mature at 10-12 years old and females at 5-7 years. In California, bottlenose dolphins have sex year-round, but mate for reproduction in the spring and fall, with most births in the fall. Gestation lasts about a year and a half and a calf nurses for up to a year and a half, but can stay with its mother for up to three years. Females can give birth every two years, but the average is three years. In the fall or spring, be on the look-out for mothers with incredibly cute calves.
Is it a shark?
Because of their sickle-shaped dorsal fin they are sometimes mistaken for sharks. If the dorsal fin moves up and down it’s a dolphin. Dolphins swim by arching their back up and down (often called porpoising) while sharks swim in a straight line with the dorsal just above the surface. Sea Lions can also swim in a similar porpoise fashion, so look for the dorsal fin to make sure it’s a bottlenose dolphin.
They can travel over 18 miles an hour, or just leisurely move along, occasionally stopping and either feeding, playing a bit, or mating. They commonly eat anchovies, sardines or rockfish and will dive for bottom-dwelling fish, crabs, eels, or other morsels.
Pacific White-sided Dolphin
Pacific white-sided dolphins (Lagenorhynchus obliquidens) are the second most common dolphin in Monterey Bay after bottlenose dolphins. They can be seen year-round but especially during the fall. They are very playful, highly social and large schools are often seen — sometimes numbering in the thousands.
Risso’s dolphins (Grampus griseus) are relatively common off the coast of California, and are often seen in small groups of 10-30 animals.
Northern Right Whale Dolphin
Northern right whale dolphins (Lissodelphis borealisare) are typically found in schools of 100-200 individuals but the groups can be as large as or larger than up to 2,000-3,000 individuals.
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- The Bottlenose Dolphin: Description, Diet, Conservation and Behavior Brittany Wagner, Yahoo Voices.
- Bottlenose Dolphin. Sea World Parks and Entertainment.
- Bottlenose Dolphin (Tursiops truncatus). NOAA Fisheries website.
- Seasons in the Sea website, by Kim Fulton-Bennet.
- Whales, Dolphins, and Porpoises of the MBNMS. Monterey Bay National Marine Sanctuary website.
- Whale Watching. Monterey Bay National Marine Sanctuary website.
- NOAA Photo Library Website.
- Porpoise. Wikipedia.
- Dolphin. Wikipedia.