Understanding the Unique Traits That Define Mammals, Including Cats

Humans, dogs, and dolphins are all mammals — but are cats? Let’s work our way through the taxonomy of the animal kingdom to find out — and figure out where exactly cats fit!

Kingdom: Animalia

Plants, fungi, and protozoa all fall into their own kingdoms, but cats fall under one of the most diverse and sophisticated kingdoms of all: Kingdom Animalia. This kingdom constitutes every animal all the way down from the smallest ant to the most massive blue whale.

All members of the animal kingdom are multi-celled and make use of aerobic respiration. Animals are capable of movement and reproduce sexually. Of course, we’ll need to make things significantly narrower if we want to get closer to the classification of a cat.

Phylum: Chordata

While a few members of the phylum Chordata don’t have backbones, the majority of its members are defined by possessing a spinal column that’s surrounded by nerve endings that extend to the rest of the body. Chordates are one of the most diverse phyla within the animal kingdom, but there are some similarities that are shared among most of them.

Some of these similarities include a rudimentary brain structure that directs sensory organs as well as a closed circulatory system for transporting blood throughout the body. All cats are unified by a sophisticated brain structure and sensory organs, but they share their phylum with creatures as wide-ranging as fish, crocodiles, and birds.

Infraphylum: Gnathostomata

While infraphyla aren’t universally recognized parts of the taxonomic system, they do allow for some narrower classification of a given phylum. Gnathostomes are vertebrates that possess a jawbone.

Organisms under this classification are descended from cartilaginous and bony fishes, but members of Gnathostomata have managed to express this trait in increasingly sophisticated ways — whether that takes the form of the skull-crushing jawbone of the jaguar, the tool-like tusks of the African elephant, or the jagged mouth of a great white shark.

Superclass: Tetrapoda

As amphibians developed and began to crawl from the water for life on land, they gave birth to the identification of superclass Tetrapoda — and all of their descendants fall into that category.

Cats have retained the four legs of their tetrapod ancestors and have adapted them to be more effective killers — with members of the cheetah species capable of reaching speeds of up to 80 miles per hour. Others — like the black panther and even the domesticated pet cat — have adapted their four legs to climbing and can navigate tree canopies as ably as they can the ground.

Class: Mammalia

It’s been roughly 200 million years since the first mammals came into being, but they continue to be a fascinatingly diverse and innovative form of life. There are six traits widely recognized in mammals, including cats.

1. Sophisticated inner ear — The shape of feline ears and the complex muscles that allow them to control each ear independently provide them with a sense of hearing that goes well beyond that of both humans and dogs.
2. Mammary glands — All mammals can produce milk to nurse their young, and almost all mammals have grown nipples to assist with the process of nursing. The average domestic pet cat will nurse for six to eight weeks before moving on to solid food.
3. Hair or fur — While the color, thickness, and pattern may vary, every mammal on the planet grows some sort of fur or hair. This primarily serves as a form of insulation against the cold, but it can also be used for camouflage or even a defensive measure. Cats are no exception!
4. Diaphragm — The diaphragm helps regulate airflow into the lungs — and when combined with the high metabolism of mammals, it allows them to be more mobile and active than many other animals. In addition to helping a cat breathe, the diaphragm is also used when a pet cat purrs.
5. Hearts with four chambers — Every chordate has an internal circulatory system, but only mammals, birds, and crocodilians have evolved to possess a four-chambered heart. The result is a more efficient cardiovascular system than amphibians, fish, and most reptiles.
6. Lower jaws made from one bone — Hinged jaws aren’t unique to mammals, but all members of the class are defined by the presence of a hinged jaw with a lower jaw made of a single piece. Cats in particular have developed jaws that can open very wide, allowing them to snap the necks of prey with a single bite.