The Difference Between Invertebrates and Vertebrates

We all remember elementary school Biology classes where we learned about the Animal Kingdom and the Plant Kingdom. One of the main pieces of information we learned was about invertebrates and vertebrates. As time passed, we probably only remember the core point: invertebrates have no backbone. However, if you’re a prospective exotic pet owner, it will come in handy to know key points about both. Below, you’ll find out more about the difference between vertebrates and invertebrates.

What is an invertebrate?

An octopus, one of the most intelligent invertebrates.
The octopus is one of the smartest invertebrates. Photo by Serena Repice Lentini on Unsplash.

Simply put, invertebrates are creatures with no spinal cord or skeletal system. They are generally not complex; they have simple respiratory and circulatory systems and do not have rigid body structures.

The majority of animals on earth are invertebrates. Common types of invertebrates include insects (like ants and butterflies), arachnids (spiders and scorpions), crustaceans (crabs and lobsters), and mollusks (octopuses and snails). Worms and jellyfish (annelids and cnidarians, respectively) are also invertebrates.

What is a vertebrate?

Vertebrates are animals that have spinal cords and backbones (save for hagfish). They have a complex central nervous system and possess high intelligence.

There are fewer than 60,000 types of vertebrates on the planet. Some common types of vertebrates include fish (sharks and coelacanths), amphibians (frogs and newts), reptiles (snakes and lizards), birds (eagles and parrots), and mammals (humans, cats, and dogs).

What are the roles of invertebrates and vertebrates?

Ecologically, invertebrates and vertebrates both have importance. Many invertebrates function as a natural food source for vertebrates (like shrimp for predatory fish and insects for lizards). They also help with the environment, such as with the pollination of flowers thanks to bees and the aeration of soil thanks to worms. Vertebrates can help keep pest population under control and prevent certain species from becoming invasive or overrunning an ecosystem.

What is the difference between vertebrates and invertebrates?

The presence of the spinal cord is what separates invertebrates and vertebrates. Beyond that, we can examine more specific differences.

  • Exoskeleton: Exoskeletons are external coverings that provide support. Because vertebrates have internal support with the spinal system, they do not have or need exoskeletons. Many invertebrates do have exoskeletons (such as insects and crustaceans).
  • Size: Due to the lack of a skeletal support system, most invertebrates do not grow very large, nor are they capable of very high speeds. There are a handful of invertebrates that can grow large, such as giant squids, but many are small. In contrast, the largest creatures on earth are all vertebrates (whales, elephants, and giraffes). Similarly, the fastest animals on land, sea, and air (cheetahs, black marlins, and peregrine falcons) are all vertebrates. However, the horsefly can reach speeds of up to 90 mph.
  • Eyes: Invertebrates tend to have sets of compound eyes, but vertebrates do not. This is for functionality; vertebrates generally can’t see different polarizations of light because they do not need to, and invertebrates do not necessarily need exceptional image resolution.
  • Body symmetry: Body symmetry is the shape of the body relative to itself. Vertebrates have bilateral body symmetry, which means that if the body were split in half down the middle, the sides would mirror each other. Invertebrates can also have radial symmetry, in which the body is the same from a central point of the body as opposed to two halves. Think of the difference between humans and starfish, or dogs and jellyfish.
  • Nutrition: Vertebrates have heterotrophic nutrition, meaning they cannot make their own food. Invertebrates may be heterotrophic, but they can also be parasitic (feeding off other organisms) or autotrophic (making their own sustenance).

In all, many invertebrates and vertebrates share numerous characteristics. However, invertebrates have the potential to stray and may have differences in some areas, while vertebrates generally do not. For example, vertebrates do not have radial body symmetry, but invertebrates can. The presence of only one characteristic (beyond the presence or lack of a backbone) is not enough to classify a creature as a vertebrate or an invertebrate.

What’s the intelligence difference between vertebrates and invertebrates?

Because vertebrates tend to be larger, they have correspondingly larger brains and are capable of higher thought processes. Many vertebrates are capable of problem-solving (rats), social constructs (elephants), group communication (dolphins and prairie dogs), using tools (otters and primates), and more. Dogs in particular are known for their high intelligence levels, as evidenced by seeing-eye dogs, therapy dogs, and drug-detection dogs.

Many invertebrates rely on instinct to move through their lives, and they seldom learn from errors or mistakes. However, creatures like octopuses are known to possess very high intelligence levels and self-awareness.

Who can survive better?

Each type of organism may be better suited to specific habitats. For example, simple invertebrates can survive in extremely harsh conditions. Tardigrades are among the most resilient; desert ants can live in areas exceeding 140 degrees Fahrenheit; and Pompeii worms can survive near hydrothermal vents below the floor of the ocean.

There are many vertebrates that have adapted to harsh conditions, though. Take Emperor penguins, which can thrive in temperatures below 40 degrees Fahrenheit. Camels can survive in the desert, where temperatures exceed 120 degrees Fahrenheit – and they can go without consuming water for over a week.

What’s easier to own as a pet, an invertebrate or a vertebrate?

A pet tarantula, an invertebrate.
A pet tarantula is one of the most common invertebrates to keep in your home! Photo by Image by missie26870 from Pixabay.

The numerous differences between invertebrates and vertebrates can come into play when deciding on what kind of pet you want. If you want a pet that will respond to you and has a more active and intelligent lifestyle, you would probably prefer a vertebrate, whether it’s a cat, snake, dog, hamster, or iguana. On the other hand, if you want a pet that is easy to maintain, you can choose an invertebrate like a tarantula or a scorpion.

You simply need to decide if you want your pet to be engaged with you. Many invertebrates operate on instinct, as said earlier, so they simply see other organisms as threats, non-threats, or food.

Call for More Information on Pet Invertebrates or Pet Vertebrates

Now that you know the difference between an invertebrate and a vertebrate, you can make an informed decision about which you want for a pet. You might be a person who favors tarantulas over puppies, or you might want a snake instead of a kitten. No matter what, we can help you choose the right exotic pet for you. Call Allan’s Pet Center to take the first step towards owning your new exotic pet. 

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