Introduction
Cats (Felidae) and snakes (Serpentes) seem very different at first glance. Cats are furry, four-legged mammals that are popular as pets. Snakes are reptiles with long, legless bodies covered in scales or scutes. Despite their obvious differences, some people wonder if cats and snakes might actually be related in some way. Certain similarities, like the structure of their eyes, their predatory behaviors, or even the ability of some cats to “hiss” have led to speculation that the two species share a closer evolutionary link.
Taxonomy of Cats
Cats belong to the kingdom Animalia, phylum Chordata, class Mammalia, order Carnivora, and family Felidae. The kingdom Animalia includes all animals. Phylum Chordata includes animals that possess a backbone. The class Mammalia includes animals that have fur and produce milk to feed their young. The order Carnivora includes meat-eating mammals. Finally, the family Felidae includes all cats, both big and small (https://en.wikipedia.org/wiki/Cat).
Taxonomy of Snakes
Snakes belong to the kingdom Animalia, phylum Chordata, class Reptilia, order Squamata, and suborder Serpentes. Within the Serpentes suborder, there are over 20 families of snakes, with some of the largest families being Colubridae, Elapidae, Viperidae, and Pythonidae (Wikipedia).
More specifically, snakes are placed into the following taxonomic hierarchy:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Reptilia
- Order: Squamata
- Suborder: Serpentes
- Families: Colubridae, Elapidae, Viperidae, Pythonidae, and many more
Within the Serpentes suborder, scientists have identified over 3,600 existing snake species. Snakes display incredible diversity in terms of morphology, behavior, habitat, and geographic range (ScienceDirect). However, they all share the distinctive elongated body shape and lack of limbs that characterizes snakes.
Evolutionary History
Cats and snakes evolved on completely separate evolutionary paths over 100 million years ago. Cats are part of the mammalian class, while snakes are reptiles. Mammals and reptiles share a common ancestor from over 300 million years ago, but began to diverge evolutionarily very early on.
The earliest ancestors of cats emerged around 35 million years ago during the Oligocene period. Some of the earliest cat-like mammals were Pseudaelurus and Proailurus, which evolved traits we associate with modern felines like specialized carnassial teeth for shearing meat and retractable claws. Over millions of years, these early cat ancestors continued to evolve and diverge into the different feline lineages we known today like lions, tigers, leopards, and domestic cats.
Snakes evolved from ancient reptiles over 100 million years ago during the Cretaceous period. Some of the earliest known snake fossils belong to the Cretaceous snakes Eophis and Pachyrhachis. Primitive snakes evolved from lizard-like ancestors and lost their limbs over time, developing elongated bodies for burrowing and hunting prey. Like cats, snakes continued to evolve into the many families we know today including pythons, boas, cobras, vipers, and more.
So while cats and snakes overlapped temporally, evolving during the Cretaceous and into the Cenozoic era, they did so on completely separate branches of the evolutionary tree with only a distant common ancestor hundreds of millions of years prior.
DNA and Genetics
Cats and snakes are not closely related genetically. They belong to different classes of vertebrates. Cats are mammals, belonging to the class Mammalia, while snakes are reptiles, belonging to the class Reptilia. This means they have very different evolutionary histories.
At a genetic level, cats and snakes have a number of key differences. Mammals have 78 chromosomes, while most snakes have 36 chromosomes. Additionally, mammals and reptiles have different types of sex chromosomes – mammals have X and Y chromosomes, while snakes have Z and W chromosomes for determining sex.
One study that examined the mitochondrial DNA of cats and snakes found that the two species shared only 15-20% genetic similarity. Their last common ancestor was a primitive amniote that lived over 300 million years ago. Since then, mammals and reptiles have evolved very distinct genetic profiles and characteristics.
While cats and snakes have converged on some similar physical traits like slit-shaped pupils, this is an example of convergent evolution rather than shared ancestry. Their eyes evolved independently to serve the function of a predatory hunter. Overall, cats and snakes are genetically very distinct despite some superficial commonalities.
Physical Characteristics
Cats and snakes have very different physical characteristics. Cats are mammals with fur coats covering their bodies, four legs with paws and retractable claws, a long flexible tail, and a head with eyes, ears, nose, mouth, and whiskers. Snakes on the other hand are reptiles with dry, scaly skin rather than fur. Snakes are legless, with elongated bodies and tails. Rather than paws, snakes have unforked tongues which they use for smelling. Their skulls are very flexible allowing them to swallow large prey whole.
Cats are terrestrial animals, living on land and able to climb trees and other structures. Snakes may be terrestrial, aquatic, fossorial (burrowing), or arboreal (tree-dwelling). Some snake species like rattlesnakes and vipers have specialized infrared-sensitive receptors that help them hunt warm-blooded prey like rodents (Source). Cats also rely heavily on their vision for hunting, specifically their ability to see well in low-light conditions.
While cats and snakes share some common abilities like being stealthy hunters with flexible spines, their bodies have adapted very differently to their ecological niches. Cats have fast reflexes, sharp claws, and strong jaws for capturing and killing prey on land. Snakes rely on constriction or venom to subdue their prey before swallowing, aided by their limbless bodies, loose jaws, and expandable skin.
Behaviors
Cats and snakes exhibit some distinct differences in their behaviors. Cats are predatory hunters and primarily hunt small mammals, birds, reptiles, and insects. They rely on stealth and agility to stalk prey. Snakes are also predatory hunters, but they typically ambush prey by striking quickly and injecting venom. They swallow prey whole.
Cats are more social than snakes. While some snake species aggregate in large groups during certain times of year, most are solitary. Cats may hunt alone but often live in social groups and colonies. Snakes do not nurture their young, whereas mother cats care for kittens for the first several months of life.
Reproductively, cats are polygynous, meaning one male mates with multiple females. Snakes exhibit a range of reproductive strategies, including oviparity (egg laying) and viviparity (live birth). Additionally, some snake species are polygynous while others are polyandrous (one female mates with multiple males).
When threatened, cats may hiss, arch their backs, fluff up fur, or scratch. Snakes rely on camouflage for protection and will usually flee threats. However, some snakes may exhibit defensive behaviors like coiling their bodies, inflating their heads, or biting when cornered. (1) (2)
Ecological Roles
Cats and snakes occupy different ecological niches and play different roles within ecosystems. Snakes are exclusively carnivorous and act as predators, helping to regulate populations of their prey species like small mammals, birds, amphibians and other reptiles (1). Many snake species specialize in certain types of prey, for example the black ratsnake focuses on small rodents while the eastern kingsnake eats other reptiles. By controlling prey populations, snakes help maintain balanced ecosystems.
Cats are also predators, hunting small vertebrates like rodents, birds and reptiles. However, domestic cats hunt even when not hungry, killing much more prey than they need to survive (2). While snakes are part of natural ecosystems, domestic cats are introduced predators that can severely impact native wildlife. Cats have contributed to at least 63 global extinctions, especially on islands which harbor naive, endemic animal populations (2).
In terms of habitat use, snakes occupy diverse niches including underground burrows, tree branches, leaf litter, and aquatic environments. Some species are habitat specialists, while others are habitat generalists. Cats tend to be more habitat generalists, occupying areas in and around human settlements.
Overall, snakes play an important role as natural predators integrated into food webs. But domestic cats, as an introduced species, can be ecologically destructive predators in environments where native species lack appropriate defenses (3).
Domestication
Cats and snakes differ significantly when it comes to domestication and interaction with humans. Cats have a long history of domestication, having been tamed by humans as early as 7500 BCE in the Middle East (Cat vs Rattlesnake: Who Would Win in a Fight). Over thousands of years, cats were bred to be good hunting companions and pets. This has led to strong bonds forming between cats and humans, with cats being one of the most popular companion animals today.
In contrast, snakes have never been truly domesticated. While some individual snakes can be tamed, the species as a whole remains wild (When Snakes Mess With The Wrong Cat). Humans have little control over breeding and genetics of snakes. Interactions between snakes and humans tend to be characterized by fear and caution, rather than companionship. Snakes are more likely to be kept as exotic pets or in zoos compared to the intimate family bonds that can form with pet cats.
Overall, the domestication process has produced close ties between cats and humans over thousands of years. Snakes remain essentially wild animals that have not undergone selective breeding and domestication by humans.
Conclusion
In summary, while cats and snakes share a common ancestor in ancient reptiles, they have followed vastly different evolutionary paths over hundreds of millions of years. Cats are mammals, while snakes are reptiles. They belong to completely separate taxonomic orders, with cats in Carnivora and snakes in Squamata. At the genetic level, the two species have major differences in their DNA, chromosomes, and reproductive systems.
Cats and snakes have distinct physical traits optimized for their respective lifestyles. Cats are predators with flexible spines, retractable claws, acute vision and hearing, and specialized teeth for hunting and eating meat. Snakes are legless reptiles with elongated bodies covered in scales, movable jaws for swallowing large prey, and heat-sensing pit organs. They employ constriction or venom to subdue their quarry.
In terms of behavior, cats are social animals that exhibit playing, grooming, and affectionate behaviors. Snakes are typically solitary and more instinct-driven. Domestically, cats have lived alongside humans for thousands of years, while snake domestication is limited. In nature, cats help control rodent and bird populations as predators, while snakes play roles as predators and prey within ecosystems.
While sharing common ancestry, cats and snakes have undergone separate journeys over the course of evolution to become two very distinct types of animals. They differ genetically, physically, behaviorally, and ecologically in very pronounced ways.
