Is a Seahorse An Invertebrate or a Vertebrate?

Is a seahorse an invertebrate or a vertebrate? Well, a seahorse is not an invertebrate. It’s a vertebrate animal as the creature has a backbone in its body. Be noted the characteristics and features of a seahorse are slightly unusual from other vertebrates. But still, they belong to the vertebrate group.

I will discuss many unknown and interesting facts about Seahorse in this article. If you read this article, you will be able to learn about the body structure of a Seahorse. Keep scrolling if you want to clarify your confusion regarding Seahorse’s classification.

Invertebrates and Vertebrates: Things To Know

Invertebrates and vertebrates are two classifications of phylum Chordata. The most identical differences between these classes are that invertebrates don’t have a spine, whereas vertebrates do.

Let’s take a closer look at these classes:

  • Invertebrates

The animals of this group don’t have any backbone. The circulatory system of their body is also open type. In most cases, they are slow-moving small animals. Their bodies are quite small and have bilateral and radial body symmetry.

Animals are multicellular and also don’t possess any cell walls. Besides, they move slowly and have an unorganized service system. Interestingly they have compound eyes that vertebrates lack. Besides, their reproductive system is surprisingly pretty fast.

  • Vertebrates

A backbone is the main distinguishing feature of vertebrates. They possess a closed circulatory system in their body. Vertebrates also have a more developed nerve system than invertebrates.

In most cases, vertebrate animals are fast-moving and larger animals, at least faster than invertebrates. Also, they don’t have any compound eyes. Vertebrate animals only have bilateral symmetry.

Almost 95-98% of animal species on the earth belong to the group invertebrates, and only 2-3% of species of animals are vertebrates.

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Is a Seahorse an Invertebrate or a Vertebrate?

A seahorse is a vertebrate animal. Vertebrate animals have vertebrae and skulls, and the seahorse has both.

Invertebrates don’t have any vertebral column and don’t also develop it from the notochord. This group mostly comprises arthropods, annelids, and cnidarians classes of animals. Seahorses are animals of the class Actinopterygii. That means they are not invertebrates.

Unlike other vertebrate animals, Seahorses don’t have any endoskeleton. But the most important feature “backbone” present is the Seahorses’ body. That’s why other exceptions are neglected while marking it as a vertebrate animal.

seahorse bones
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The group of seahorses is a group of unusual vertebrates. The backbone of seahorses’ is surrounded by an exoskeleton that protects the body’s internal parts from external harm. The spine is protected well by the vertebrae.

What Is The Classification Of A Seashore?

A seahorse is a sea creature of the genus Hippocampus. There are almost 50 species of seahorses in this genus. The word “ Hippocampus” came from the Greek word hippocampus. Here, “hippos” means “horse” and “Campos” means “sea animal”.

Aren’t you curious about the detailed scientific classification of a seahorse? Here it is:

Domain: Eukaryota

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Syngnathiformes

Family: Syngnathidae 

Subfamily: Hippocampinae

Genus: Hippocampus 

Do Seahorses Have Bones?

Yes, seahorses have bones. They belong to the Osteichthyes class. This class is also called the class of bony fish.

Osteichthyes or bony fishes are aquatic vertebrates with bony endoskeletons in their adult form. In the case of seahorses, although they are bony fishes, they don’t have any scales. 

Their skin is very thin and is stretched over a series of bony plates. Throughout their body, these plates are arranged in rings. The number of rings varies from species to species.

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Seahorses are slow swimmers, and they need to rest frequently. These plates give the seahorses the advantage of bending their tails to hold or grasp any stationary object. By this, they don’t get flown away by water flow. These plates of seahorses also aid in their camouflage.

Watch this video to learn more about bony fishes. 

Do Seahorses Have An Exoskeleton or Endoskeleton?

Seahorses have exoskeletons. They don’t have any endoskeleton to protect them from external harm. The exoskeleton of seahorses acts on this function.

Do you know what exoskeletons and endoskeletons are? Let me enlighten you a little about this. Endoskeleton is an internal structure composed of a mineralized and hard structure to support and protect the body. On the contrary, the exoskeleton protects the body from the outside.

Most fishes have an endoskeleton. But, a seahorse’s body is composed of articulated bony plates around the central vertebral column. These hard plates, known as exoskeletons, are fused with a fleshy covering. This exoskeleton protects Seahorses’ bodies to a great extent.

Does A Seahorse Have A Backbone?

Yes, a seahorse has a backbone. But, unlike normal vertebrate animals of phylum Chordata, it doesn’t have ribs. Instead, they have rings that go down into their tails.

Normal vertebrate fish of the Chordata phylum have two sets of ribs that are attached to the backbone. But in the case of a seahorse, there is no existence of ribs. They have armed bony plates which cover their body.

A seahorse’s body can be divided into 3 parts: head, trunk, and tail. The trunk and tail part consists of a series of rings. The vertical spine, called the trunk ridge, runs down from the trunk to the tail’s tip. 

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There is one superior trunk ridge, one inferior trunk ridge, and two lateral trunk ridges in the body of a seahorse.

The rings around the trunk to above the tail are called trunk rings. And the series of rings from below the anal fin to the tip of the tail is known as tail rings.

Is A Seahorse A Mammal Or A Fish?

A seahorse is a fish. Because it demonstrates all the true characteristics of a fish, its exceptional body structure may not seem like a fish. Still, seahorses belong to the fish family “Syngnathidae”.

A Seahorse isn’t from any mammal class or mammalian family. Mammals have a mammary gland as the most important distinguishing feature. Moreover, they give birth to their young and also feed them. 

On the other hand, seahorses give birth through the laying process. Most importantly, they don’t have mammaries. Though it has the word “horse” in its name, it’s not a mammal-like horse. In short, seahorses are bony fishes.


A seahorse is a very mysterious creature of the ocean. Its features are more exceptional than any other coexisting animals of the same group. That’s why much confusion often arises regarding Seahorses. One of them is “Is a seahorse an invertebrate?”

If you have been here from the beginning, I hope you are now crystal clear about the fact that they are vertebrates. Besides, you also now know the detailed classification of seahorses. Furthermore, now you also know the skeleton structure of their body.

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