A Pacific White-Sided Dolphin swims alongside a boat off Newport Beach, California
For those who are fortunate enough to live near the coast of California, Dolphin sightings are a frequent delight. Dolphins are a diverse group of marine mammals found in all of the world’s oceans, but they are especially abundant in California. The California coast is home to numerous species of dolphins, each with their own unique characteristics and behaviors. An afternoon spent at the beach will very often result in a sighting of these magnificent and majestic animals frolicking in the waves.
For those who may not know, dolphins and porpoises are toothed whales. Both porpoises and dolphins are members of the same scientific order, Cetacea, which includes all whales, including the magnificent blues, grey whales and humpbacks that also ply the California coast.
The exact number of dolphins off the California coast is impossible to know since many species migrate and no authoritative study of their total numbers has ever been published. But one estimate of the dolphin population in Southern California suggests that well over half a million live between the frigid, rocky coastal waters of Monterey and San Diego. Scientists have documented 11 species of dolphins in California’s waters alone. We take a look at a few of those here.
One of the most common, and beautiful, dolphins found off the coast of California is the Pacific White-Sided Dolphin (Lagenorhyncus obliquidens). These dolphins are easily recognized by their distinctive markings, which include a white underbelly and gray and white stripes along the sides. White-Sided Dolphins can reach up to 400 pounds and can grow to 8 feet in length, with males typically being larger than females. They are also known for their energetic and playful behavior, often bow-riding the waves alongside boats and performing wonderful acrobatics in the air. Boaters and whale watchers can witness pods of these animals following their boat for half an hour or more, often swimming on their sides near the surface and gazing up with attentive eyes.
White-sided dolphins feed on a variety of prey, but mostly consume fish and squid. They are skilled hunters and have been known to work together in groups to corral and capture their meals.
Another species found off the California coast is the Common Dolphin (Delphinus delphis). These dolphins have a distinctive sleek, hydrodynamic shape, with a dark gray or black dorsal region and a light gray or white underbelly. Common Dolphins are also known for their high level of activity, often seen jumping and playing in the water. Common dolphins can travel 100 miles in a single day.
This species is one of the most well-known and widely distributed marine mammals, and is often associated with playful acrobatics and a high level of intelligence. California is home to several large “super pods” or “megapods” of Common Dolphins that are often seen by boaters or whale-watching tours. As the American Cetacean Society explains, common dolphins typically travel and hunt in large herds of hundreds or even thousands. One resident megapod frequently forages between Ventura and Dana Point.
A Pacific White-Sided Dolphin
Common dolphins have been the subject of numerous studies examining their cognitive abilities. They are known to have complex social relationships and to exhibit behaviors that suggest a high level of problem-solving ability and adaptability. In addition, they are capable of using tools, such as seaweed, to herd fish and protect themselves from predators. They also have excellent memories and are able to recognize individual dolphins and remember past experiences.
The Bottlenose Dolphin (Tursiops truncatus) is another species that can be found off the coast of California. This species is easily recognizable due to its large size and beak-like snout. Bottlenose Dolphins are known for their intelligence and playful nature, and are often (unfortunately) used in marine mammal shows and research programs.
Bottlenose dolphins have a complex mating system that involves a variety of behaviors, including courtship displays, vocalizations, and physical contact. Female Bottlenose dolphins give birth to a single calf every three to five years, and the calves are nursed by their mothers for up to a year. Male Bottlenose dolphins compete for access to females, and the strongest and most dominant males are the most successful at mating.
A lesser-known (and seen) species found in the waters of California is the Risso’s Dolphin (Grampus griseus). These dolphins are identified by their tall, curved, sickle-shaped dorsal fin located mid-way down their back. Often they also have distinctive scars and scratches, which are believed to be caused by “teeth raking” between other dolphins. They also frequently have circular markings, likely from encounters with squid or lampreys. Risso’s Dolphins are generally less active than the other species found in the area, and are often seen alone or in small groups.
Finally, the Dall’s Porpoise (Phocoenoides dalli) is another species that can be found in the waters off the California coast. These dolphins are identified by their short, stocky bodies and small triangular dorsal fins. Dall’s Porpoises are known for their speed and agility, and are often seen riding the bow waves of boats.
Few places on earth match the coast of California for the sheer number and variety of dolphins that swim in the cool, nutrient-rich waters that well up from the state’s deep canyons. So next time you’re near the coast, keep an eye out for these incredible creatures and enjoy the show!
