Do Trout Have Backbones? A Skeletal System Breakdown

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Trout in the water.

Yes, trout, like all fish, are vertebrates. They possess backbones and full skeletal systems that assist in mobility and protection.

It may seem like an odd question, but given what swims in the waters the world over, I guess it’s legit.

If you’ve ever wondered about the bone structure of trout, my guess it’s because you wanted to know how to clean one. And, if you’ve ever cleaned a trout, you know they do, indeed, possess backbones. And ribs, skulls and jawbones

In fact, I would say that trout are some of the bonier game fish. The good news? Most of the bones are small and easy to work around if you harvest trout for food. 

The Skeletal Framework

A trout’s skeleton is actually made up of two sections. First, there’s the axial skeleton. This is the fish’s main bone system. It includes the skull, the backbone and the ribs. 

The second section of a trout’s skeleton is its appendicular skeleton. The appendicular skeleton is attached to the axial skeleton and includes the pectoral fins and the pelvic fins.

The axial skeleton is the bone system that projects the fish’s vital organs and connects to the trout’s muscular system. The appendicular skeleton is what helps the fish swim. 

The Bones

Chris holding a trout from the water.
How you hold a trout matters. You want to support its weight from the middle, because its bones aren’t designed to support the fish’s weight out of the water.

Trout bones are made of flexible cartilage, and, while they serve a purpose, remember that they’re designed to support the fish in a virtually weightless underwater environment. 

That’s why it’s important to handle trout carefully when you prepare them for release. Their bones aren’t constructed to support the fish’s weight out of water for a longer period of time. 

If you’ve ever eaten a trout, chances are, you’ve probably had to pick rib bones, or “pin bones” out of your mouth. The rib bones, as they descend around the fish’s organs, are very thin. 

Often, when you filet a larger trout, you’ll slice a few pin bones. You can remove them before you cook the fish. 

A trout’s ribs aren’t “floating bones” that are unattached to anything else. They are firmly attached to the trout’s spinal colum.

The Skull and Jaws

Close up image of trout held by a man.
The trout’s skull and jaws are made up of the fish’s most-dense bones.

The most dense bones on any trout are the bones around the skull and the jaws. Evolutionary logic has it that a trout’s skull needs to be harder and denser because of the battles it endures every year during spawning season, 

And, the jawbones are dense, too. But they’re even more special than you might think. 

Every year, when trout prepare to spawn, they undergo physiological changes. The lower jaw develops a hook, called a kype, and it sports bigger teeth. 

The trout uses this impressive kype to jockey for the best position during the spawning run. Male trout, in particular, develop very pronounced kypes, and they will fight, sometimes to the death, for the right to spawn with migrating females. 

Final Thoughts

Like all fish, trout are classified as vertebrates, and they possess a backbone and a full skeletal system. Trout actually have two skeletal sections. The main skeletal system is the axial skeleton. This includes the spine, ribs, skull and jaw. 

The appendicular skeleton includes the fish’s fins and helps the fish swim. 

Trout are hardy animals, and their skeletal systems are strong. But they’re not built to support the fish’s weight out of the water, so be careful when you’re handling fish you intend to release. 


Do Trout Have Spinal Cords? 

In addition to possessing a full skeletal system, trout also possess a full nervous system, and that includes a spinal cord that runs the length of the fish’s backbone. 

Is a Trout a Vertebrate or Invertebrate?

Trout have spines and bones. They are vertebrates.

Can Trout Bones Break?

Absolutely. But trout bones are cartilaginous, and their bones are flexible and somewhat soft, making it difficult to break a trout’s bones.

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