My Neighbor Gave Me a Bag of These Strange "Horned Nuts"—What Are They and How Do You Eat Them?

These unusual horn-shaped water caltrops may look intimidating, but they're a traditional food enjoyed in many parts of Asia.

At first glance, they look more like tiny bat heads or devil horns than something you would eat. It's no surprise that many people who receive a bag of these unusual fruits ask the same question: "What are they, and how do you eat them?"

These distinctive fruits are commonly known as water caltrops. Depending on the region, they are also called buffalo nuts, devil pods, horn nuts, bat nuts, ling nuts, or water chestnuts (although they are different from the common crunchy water chestnut used in stir-fries).

Despite their intimidating appearance, water caltrops have been eaten for centuries across many parts of Asia.

What Exactly Are Water Caltrops?

Water caltrops are the fruit of aquatic plants in the genus Trapa. They grow in lakes, ponds, and slow-moving waterways where the floating plants spread across the water's surface.

The mature fruits develop a hard shell with two or more sharp "horns," giving them their unique appearance.

Inside the shell is a firm, white, starchy kernel that is completely edible after cooking.

Why Do They Look So Strange?

The curved horns help distinguish the fruit from other aquatic plants. Different species can produce slightly different shapes, but all contain the same edible seed inside.

Although they may look intimidating, the horns simply protect the seed during development.

How Are They Eaten?

The most common preparation is surprisingly simple.

After harvesting, the fruits are:

• Washed thoroughly
• Boiled in water until tender
• Allowed to cool slightly
• Cracked open with a knife or nutcracker
• The white kernel inside is removed and eaten

The cooked flesh has a mildly sweet, nutty flavor with a texture somewhere between chestnuts and potatoes.

Some people enjoy them warm, while others eat them chilled as a snack.

Are They Nutritious?

Water caltrops are naturally rich in starch and provide carbohydrates that supply energy. They also contain dietary fiber and small amounts of minerals and antioxidants.

Because they are filling and naturally low in fat, they have long been included in traditional seasonal diets in many Asian countries.

Where Are They Popular?

Water caltrops are commonly enjoyed in countries such as:

• China
• Vietnam
• India
• Thailand
• Taiwan
• Parts of Southeast Asia

During harvest season, they are often sold fresh in local markets and by street vendors.

Can You Eat Them Raw?

Fresh water caltrops are generally not recommended to be eaten raw. Cooking helps soften the shell, improves flavor and texture, and is the traditional method of preparation.

Always wash the fruits thoroughly before boiling, especially if they were harvested from natural waterways.

A Curious Fruit Worth Trying

Although their unusual appearance may make them seem inedible at first, water caltrops have been enjoyed for generations as a nutritious seasonal food. If someone hands you a bag of these mysterious horned fruits, don't be alarmed—simply boil them, crack them open, and enjoy the soft, starchy kernel inside.

Sometimes the strangest-looking foods turn out to be delicious.