Frogs are small, water-loving animals. Many people find they make interesting pets, although they’re more of a ‘niche’ choice. They aren’t as popular as other pets, and there are a few misconceptions about them.
I’d like to clear these up in today’s article. For example, many people mistakenly lump them together with turtles and tortoises under the category of “reptiles”.
But, while turtles and tortoises are indeed reptiles, frogs are amphibians. The confusion might come from the fact that both reptiles and amphibians are also classified as “cold-blooded” animals. To make your head spin even more, cold-blooded animals (and warm-blooded ones too, for that matter) are also classified as “vertebrates”.
So, these little guys are classified under the kingdom “Animalia”. I mean, duh, they’re obviously animals. They’re part of the subphylum “Vertebrata”, which means they’re vertebrates, and they belong to the class called “Amphibia”, which means they are amphibians.
Speaking of vertebrates, many people also wonder whether frogs have backbones or not. The shortest answer is “yes”. Frogs do have backbones, just like any other vertebrate out there. Let’s get into more detail.
Let’s see, what are vertebrates and amphibians, and what does that means when we’re talking about a frog? A vertebrate is an animal that belongs to the subphylum “Vertebrata”. This includes reptiles, amphibians, birds, and mammals.
All vertebrates have backbones and a central nervous system. Vertebrates are also characterized by bilateral symmetry. That’s a fancy way of saying their body looks the same both on the left and on the right side.
This also applies to frogs. They have two shorter front legs, two larger back legs with webbed feet, two eyes, and two nostrils. Their flat skull connects to a very short, rigid neck.
Unlike other vertebrates, frogs don’t have a large range of neck movement, which means they can’t turn their heads left or right. All of a frog’s organs are housed in a single body cavity called the “coelom”.
A frog’s backbone is made up of 9 vertebrae, compared to the 24 vertebrae found in humans. Another difference between frogs and humans (and other vertebrates) is their lack of ribs.
Their front legs are separated into two segments, the upper part and the lower part, similar to a human’s upper arm and forearm. The front legs connect to the rest of the body through the scapular bone.
The hind legs are the most interesting part of a frog’s skeletal structure. They are much longer than the forearms, and made just for jumping and leaping. A frog has two long, thick leg bones connected through cartilaginous joints. Their legs end in long, thin joints that make up the skeletal structure of their webbed feet.
What About Amphibians?
Amphibians are a class of small vertebrates that can live both inside and outside the water. This includes tadpoles, frogs, and salamanders. Frogs are the most diverse amphibians out there, with approximately 5000 species belonging to this genus.
All amphibians are ectotherms, or cold-blooded. This means that they need an outer source of heat such as sunlight to regulate their internal temperature.
Amphibians have moist, soft, and permeable skin with no scales. That’s important because frogs breathe through their skin. A thick, rigid outer layer of skin would make oxygen uptake more difficult.
To absorb oxygen through their skin, frogs need to be moist, so their skin also has multiple mucus glands. Frogs can also breathe through their nostrils and mouths.
When reproducing, amphibians need a moisture-rich environment to lay their shell-less eggs. Usually, a frog will lay thousands of eggs, usually up to 4000 at a time. After laying the eggs, the frog usually abandons them, leaving the future tadpoles to fend for themselves.
As a result, many of the thousands of eggs and potential tadpoles don’t make it too far. I guess the “parent of the year” award won’t go to frogs anytime soon.
Frogs vs Other Vertebrates
All vertebrates, including frogs, have a backbone and an endoskeleton. This is what keeps vertebrate animals from looking like gelatinous blobs. Most vertebrates also function in similar ways, having the same systems of organs. Like most other animals, frogs have a brain, heart, lungs, liver, stomach, kidneys, bladder, and intestines.
As I’ve already mentioned, frogs have no ribs and their neck bone is short and contains only one vertebra. That’s different from many other vertebrates already. Moreover, frogs don’t have a diaphragm to help with their breathing. They also have no external ears, although they do have an inner ear.
But I think the biggest difference between frogs and other vertebrates is how they grow from tadpole to adult. When a frog is still in its infancy, it looks like a completely different animal.
A tadpole has no legs or feet, looking more like a fish than a frog. While adult frogs are carnivorous, tadpoles are herbivores. Also, tadpoles breathe thanks to their gills, while adult frogs breathe through their lungs.
Frogs’ outer eyelids aren’t as complex as those of other animals. Instead of closing their eyelids shut to blink or close their eyes, frogs move their eyeballs down and inwards into their sockets. Like dogs, cats, and other animals, frogs also have a third eyelid, called the “nictitating membrane”.
Frogs have tiny and weak teeth. These teeth are only present in the upper jaw. But they can catch prey thanks to their long, sticky, and flexible tongues. When they eye their prey, they can flip out their tongue faster than you blink. No, really.
A frog’s tongue can catch small prey in under 0.07 seconds. That’s according to a 2017 scientific article written by Alexis Noel and David Hu and called “The Frog Tongue Is A High-Speed Adhesive”.
Frogs are basically freaks of nature, although not exactly platypus-tire weird. They’re cold-blooded animals, but they’re not reptiles. They have a backbone and an endoskeleton, which means that they’re vertebrates.
They have more similarities than they do differences when compared to other vertebrate animals. However, they also have unique traits that distinguish them from other animals.