On Exhibit: Monterey Bay Habitats
squid, fishes, crabs, shrimp and other invertebrates
to 3 to 4 feet (.9-1.2 m)
pygmy shark, sleeper shark; Family: Squalidae
Alaska to Baja California and worldwide in temperate and subartic waters; in depths from the surface to 3,000 feet (900 m)
As their name suggests, spiny dogfish sharks sport sharp, venomous (poisonous) spines in front of each dorsal fin. Their bodies are dark gray above and white below, often with white spotting on the sides.
Despite their small size, spiny dogfish are aggressive and have a reputation of relentlessly pursuing their prey. The name "dogfish" stems from their habit of feeding in packs—sometimes numbering in the hundreds or thousands. Gathered together, they sweep an area, eating the fishes in front of them. They'll eat almost anything they can get their strong jaws and teeth on. Newborn dogfish will even attack fishes two to three times their size.
All sharks have unique skin. It's covered with toothlike scales called denticles—unique to sharks and very similar to the teeth of all vertebrates—which make the skin rough and abrasive. In fact, shark skin was once dried and then used as sandpaper to polish wood. Today, shark skin is still cured and, after the denticles are removed, used as leather.
This shark probably has the longest gestation (pregnancy) period of any vertebrate—22 to 24 months.
Spiny dogfish sharks are long-distance travelers. One spiny dogfish tagged and released from Washington State showed up off the coast of Japan—a 5,000-mile journey.