Cabrillo Marine Aquarium

Creature Feature

Risso's dolphin
Grampus griseus

Tall dark dorsal fins are spotted in the distance. The captain says quietly under his breath, "We might have orcas." As we get a little closer and the marine mammals come into range, we see they are in fact Risso's dolphins - an identification mistake often made from a distance. We are not disappointed and look forward to good encounters with this species.
Risso's dolphin (Grampus griseus) is one of the larger dolphin species, with adults reaching lengths of 12 to 12 1/2 feet and an estimated life span of 30 years. Risso's are toothed whales with one blow hole (odontocetes), and are often found in the mixed company of other dolphins. Its bulbous head has no protruding beak, as many other dolphins do. It has a tall erect dorsal fin that is slightly curved, reminiscent of an orca. Up close, Risso's dolphins look a bit beat up and scarred with older audlts almost white in color. The patterns made by the scars can look like northwest Indian art. It's believed the scars are made by the teeth of other Risso's dolphins and by their primary food source, squid.
Generally seen in groups of 12 to 40 individuals, it is estimated there are 30,000 off the U.S. west coast and a total worldwide population of 322,000 animals. As you can see from these numbers, the species is not threatened. However, in many regions they are inadvertently taken as bycatch in many kinds of fishing gear, including drift nets, longlines and trawls. They are also hunted in Japan, Indonesia, the Soloman Islands and the Lesser Antilles. Not so long ago in our Southern California waters and off the northern Gulf of Mexico, a more common sighting would be that of a shirt-finned pilot whale. In recent years, the Risso's has replaced the short-finned pilot whale in these waters.
I hope you're out there one day when the captain says quietly under his breath, "We might have..."

- Cathy Hachigian, Whalewatch Program Chair


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Southern California Species

The Cabrillo Marine Aquarium is home to more than 200 species of animals that live in and around the waters of Southern California. Do you have a question about these and other Southern California species? Ask a Biologist.

Haliotis sp.

Young abalone with a shell size of less than 3 cm take shelter within the spines of sea urchins for protection.

Balanus spp.

Barnacles are hermaphroditic (they have both female and male sex organs).

Cetorhinus maximus

The basking shark is the second largest species of fish in the world.

Asterina miniata

When two bat stars bump into each other they begin a slow-motion “arm wrestling” match. Each sea star tries to get its arm on top of the other’s arm.

Nycticorax nycticorax

Black-crowned night herons feed at night in the same areas that other heron species feed in the day.

Prionace glauca

The blue shark has one of the largest ranges of all species of sharks.

Balaenoptera musculus

The blue whale is the largest living animal.

Lythrypnus dalli

These peaceful fish are often territorial with members of their own species.

Bocaccio   Arrow
Sebastes paucispinis

The bocaccio can live up to 45 years.

Bottlenose Dolphin   Arrow
Tursiops truncatus

The bottlenose dolphin uses echolocation to find its prey.

Pelecanus occidentalis

The brown pelican is the smallest of all pelicans and is the only one that plunges from the air into the water to catch its food.

Aplysia californica

Each Sea hare may lay up to eighty million eggs. However, most of the eggs are eaten by predators.

Leuresthes tenuis

Unlike other fish, grunion come completely out of the water to lay their eggs in the sand.

Paralichthys californicus

The California halibut is a flatfish with both eyes on one side of its head!

Mytilus californianus

While feeding, a mussel filters 2 to 3 quarts of water per hour.

California Scorpionfish   Arrow
Scorpaena guttata

The California scorpionfish has venom in its spines.

Zalophus californianus

Sea lions use their long front flippers to steer and propel themselves through the water.

Semicossyphus pulcher

The California sheephead are all born as females.

California Skate   Arrow
Raja inornata

The California Skate has a skeleton made completely out of cartilage.

Panulirus interruptus

California Lobsters do not have front claws.

Alopias vulpinus

The common thresher shark uses its long tail in a whip-like fashion to deliver incapacitating blows to its prey.

Phronima sedentaria

The eyes of this amphipod are so large that they make up nearly a quarter of the entire body.

Aequorea victoria

Crystal jellies can expand their mouth to eat prey half their size!

Zostera marina

Eel grass is a true plant (not a seaweed) and is one of the few flowering plants that grow in the ocean.

Uca crenulata

Males have a large claw that they wave back and forth like a fiddler.

Fin Whale   Arrow
Balaenoptera physalus

The Fin whale is the second largest animal after the blue whale

Hypsypops rubicundus

Garibaldi is the California State marine fish.

Hypsypops rubicundus

Garibaldi is the California State marine fish.

Macrocystis pyrifera

Under ideal conditions, giant kelp can grow about two feet a day.

Heterostichus rostratus

The giant kelpfish can quickly change color during courtship or territorial displays.

Stereolepis gigas

This fish is huge, growing over 7.5 feet long and weighing over 500 pounds.

Pollicipes polymerus

Gooseneck barnacles can live 20 years, or more.

Gray Whale   Arrow
Eschrichtius robustus

The gray whale is a baleen whale.

Carcharodon carcharias

The great white shark is capable of explosive bursts of speed and has been known to jump 3 meters (10 feet) out of the water.

Anthopleura xanthogrammica

Some fishes develop resistance to the green anemone's sting by covering themselves with mucus.

Harbor Porpoise   Arrow
Phocoena phocoena

The harbor porpoise is one of six species of porpoise

Harbor Seal   Arrow
Phoca vitulina

The Harbor seal is the most widely distributed species of pinniped.

Pagurus sp.

Hermit crabs protect their rear ends by hiding it in a snail shell.

Heterodontus francisci

The female horn shark lays a distinctive spiral-shaped egg case.

Humpback Whale   Arrow
Megaptera novaeangliae

The humpback whale has distinct patterns on the tail flukes used to identify individuals.

Paralabrax clathratus

Kelp bass reproduce by spawning (release egg and sperm into the water column) and form large aggregations in the summer months.

Orcinus orca

The killer whale, as known as the orca, is the largest dolphin.

Krill   Arrow

Thysanoessa spinifera

Krill are eaten by whales, seals, penguins, squid and fish.

Phoebastria immutabilis

The wings of a laysan albatross are adapted to lock open into a wingspan of nearly seven feet.

Triakis semifasciata

Leopard sharks are bottom feeders and are named because of their stripes.

Hemisquilla ensigera

Mantis shrimp are not true shrimp, but get their name because of their appearance.

Marbled Godwit   Arrow
Limosa fedoa

The marbled godwit has a long, slightly upturned bill with a dark tip and pinkish base.

Loxorhynchus crispatus

The masking crab decorates itself with bits of algae, sponges and bryozoans.

Minke Whale   Arrow
Balaenoptera acutorostrata

The minke whale is the smallest of the rorqual whales

Gymnothorax mordax

This eel's favorite prey is the octopus.

Norrisia norrisi

These snails travel up and down kelp every day.

Pisaster ochraceous

These sea stars are able to digest their prey outside of their bodies.

Squatina californica

The Pacific angel shark superficially looks like a ray, but is a true shark.

Eptatretus stoutii

Hagfish are considered to be the most primitive species of all living fish.

Pacific Hake   Arrow
Merluccius productus

The Pacific hake can live up to 15 years.

Scomber japonicus

The Pacific mackerel is also known as the chub mackerel or blue mackerel.

Sardinops sagax

The Pacific sardine form large schools of up to 10 million fish.

Pacific Seahorse   Arrow
Hippocampus ingens

The Pacific seahorse reverses traditional birthing roles.

Strongylocentrotus purpuratus

Sea urchins have tube feet, which they use for attachment, locomotion and feeding.

Risso's dolphin   Arrow
Grampus griseus

Adult Risso's dolphins bodies are typically heavily scarred, while calves have little or no scarring


Xenistius californiensis

These fish have an up-turned mouth to better eat plankton.

Dendraster excentricus

You can't spend these dollars, they are relatives to sea stars.

Sargo   Arrow

Anisotremus davidsoni

The sargo is the largest of the Pacific grunts.

Renilla koellikeri

A sea pansy is not a flower, but is an animal that is related to sea jellies.

Isurus oxyrinchus

The shortfin mako shark is able to elevate its body temperature almost 20°F above the surrounding water.

Enhydra lutris nereis

Sea otters do not have blubber to keep warm, instead they have very dense fur (up to one million hairs per square inch).

Sperm Whale   Arrow
Physeter macrocephalus

The sperm whale is the largest of the toothed whales and the largest toothed predator.

Pachygrapsus crassipes

The striped shore crab spends at least half its time on land, but submerges at times to wet its gills.

Cephaloscyllium ventriosum

When stressed, the swell shark can “swell” by inflating its stomach by swallowing water.

Tidewater Goby   Arrow
Eucyclogobius newberryi

The tidewater goby is an endangered species.

Octopus bimaculoides

Octopus are very smart and have well-developed eyes.

Larus occidentalis

The Western gull typically lives about 15 years, but can live to at least 25 years.

Whale Barnacle   Arrow
Cryptolepas rhachianecti

Whale barnacles live attached to the skin of whales.

White Seabass   Arrow
Atractoscion nobilis

The white seabass is the largest species of croaker in California.

Tringa semipalmata

The willet is very territorial and will aggressively defend their nesting and feeding territory.


Creature Feature Archive

      5/17/2013 Killer Whale (Featured)
      3/31/2013 Cowcod
      2/15/2013 Crystal Jelly
      11/1/2012 Risso's dolphin
      9/6/2012 Lacy Crust Bryozoan
      8/16/2012 California sheephead
      7/31/2012 Chitons
      7/17/2012 Splitnose rockfish
      2/28/2012 Green Sea Turtle
      12/26/2011 Gray Whales
      11/16/2011 California Brown Pelican
      8/23/2011 Oarfish
      2/21/2011 Pacific Mackerel
      6/28/2010 Football Fish
      3/3/2010 Grunion
      1/12/2010 E. coli, Oh My!
      7/22/2009 Cabrillo's Fossils
      3/9/2009 Garibaldi
      11/3/2008 Laysan Albatross