Range: Marine waters worldwide

Habitat: Coastal waters and deep ocean

Size: About 6 inches (15cm) tall

Diet: Phytoplankton and zooplankton

Threats: Sea stars, crabs, sea turtles, lobsters, and fish

Life span: Up to one decade or older

Transcript:

Today on Animal Fact Files we’re discussing scallops. Scallops are bivalves. They have two shells that come together at a hinge that can be open and closed at will. Other bivalves include mussels, oysters, and clams. Sometimes “spiny oysters” are also called scallops, but this episode will focus specifically on the “true” scallop family.

There are somewhere around 400 living scallop species, and they can be found in marine waters from tropical to polar regions. Scallops may live along coastlines or deeper than four miles (6,400m) beneath the ocean’s surface. They are most recognizable for the wing-like projections, called auricles, found at the hinge of their shells. They’re also some of the only bivalves that can swim.

Scallops begin their life as an egg. They can be quite productive and produce millions of eggs each year, but some can also produce sperm. These bivalves may undergo multiple sex changes throughout their lifetimes depending on the species. Sperm and eggs are released synchronously into the water column where they will be fertilized and quickly hatch into larvae. These larvae are free swimming until they settle to the ocean floor or some other surface a few weeks after hatching.

Some scallops will remain in a single spot for life, much like the oysters we’ve discussed previously, however, some species are not stuck to the place they settle and can flap their shells to fly about the ocean. They’re kind of like underwater butterflies! They do this by expelling water from their shell and creating jet propulsion. Individuals that don’t attach to surfaces often spend their time lying along a sandy or muddy sea floor.

Scallops have tentacles which determine changes in the chemical composition of the surrounding water helping them to react to changes in their environment. They also have eyes positioned along the edge of their mantle, or the soft, tentacled part of their body that hangs outside of the shell. These eyes have two retinas and can sense changes in light to alert the scallop to approaching danger.

Predators to scallops include sea stars, crabs, sea turtles, lobsters, and various types of fish. They’re also eaten by humans who consider them a delicacy in many areas. The large adductor muscle that scallops use for swimming is most often the muscle consumed by people and likely what many people think of when they think of “scallops”.

In size, scallops can reach up to 9 inches (23cm) in shell height, though on average scallops don’t grow larger than 6 inches (15cm). They are filter feeders that eat microscopic plants, called phytoplankton, and animals, called zooplankton. Depending on the species, they can live at least five years and often don’t begin breeding until they reach at least a year old. Some species can live well over a decade!

Like giant clams, their shells come in a wide range of shapes and colors. Scallops that settle on surfaces often have asymmetrical shells, though even swimming individuals may have shells with different colors or textures. Other common names for scallops include ‘fan shell’ and ‘comb shell’ which may be in reference to their appearance.

For more facts on scallops, check out the links below. Give a thumbs up if you learned something new today. Thank you to our Patrons SpikeSpiegel93, Dad, and everyone else for their support of this channel! And thank you for watching Animal Fact Files!