MCQ Detailed View

The correct answer is the Hagfish. This strange and primitive fish is known for its unusual body structure and survival features. Unlike most fish, the hagfish does not have jaws or a true stomach. Instead, it has a simple digestive system and feeds mainly on dead or dying sea animals by burrowing into their bodies.

Unique Features of Hagfish:

• Hearts: Hagfish have four hearts – one main heart and three accessory hearts to pump blood throughout the body.


• Nostril: They have only a single nostril for breathing and smelling.


• No Jaws: Instead of jaws, they use tooth-like structures made of keratin to tear food.


• No Stomach: Their food goes directly from the esophagus into the intestine.

Survival and Adaptations:

Hagfish are also famous for producing large amounts of slime as a defense mechanism. When attacked, they release a sticky slime that can block the gills of predators, forcing them to retreat. This makes hagfish almost impossible to eat for larger fish.

Biological Importance:

Scientists believe hagfish are among the most primitive living vertebrates, meaning they have been around for hundreds of millions of years with very little change. Studying them helps researchers understand the early evolution of vertebrates and the development of key body systems.

Fun Fact: Because of their unique slime, hagfish are sometimes called “slime eels,” even though they are not true eels.