If big cats exist, why are there no big dogs? Both cats and dogs have such special roles in our lives. Out of all pets, cats and dogs are the most popular, so naturally, we like to compare them to one another. But in the end, these animals are strikingly different. Still, we can’t help but wonder, if our furry little house-cat companions have giant counterparts, why don’t our dogs? Evolution, ecology, hunting behaviors, and social habits are key contributors.
Evolution
While both cats and dogs belong to the order Carnivora, they haven’t shared a similar ancestor for over 40 million years. Cats evolved into many different species around 6 million years ago, but dogs had a different path. Wolves became a species roughly a million years ago when they split from their ancestors, and dogs descended from wolves roughly 20,000-40,000 years ago. And while dogs vary greatly, they’re all the same species. Dogs only differ due to breeds. Humans have bred dogs, while cats evolved themselves, so their paths were just incredibly different. This split in their evolutionary processes laid the foundation for the vast differences between these animals.
Hunting and Social Habits
Big cats are often solitary hunters. The exception to this rule would be with lions, which are the only cats to hunt and live in groups. They have learned that this helps them compete for prey. Even though lions are fierce predators themselves, they have some competition with hyenas, leopards, and cheetahs for food. They also don’t always have as many hiding places, like trees or thick foliage, in the areas they live. Being in a group gives them more overall success when hunting and defending their food. Otherwise, every other cat species prefers to do the work alone. They don’t have to share resources with other individuals. The other big cats also live in places that allow them to be better at ambushing. They have more spots to hide and wait, giving them an advantage to being alone.
With the tools available to a canine, the hunting strategies of solitary cats just wouldn’t work. Cats use short bursts of energy to catch and consume prey. Their size and solitary hunting style require them to have powerful muscles and razor sharp claws and teeth capable of subduing and killing large prey pretty quickly. But animals like wolves are endurance hunters. They follow and harass their prey, using their more blunt claws and strong jaws to bite and injure until that prey is so weak, it can no longer go on. That’s when a pack goes in for the final kill. Ultimately, size would certainly be a detriment to canines. They would have a far harder time going the distances they do if they were larger. Marathon runners don’t look like bodybuilders, do they?
Now, there were some bigger “dog-like” animals that lived before the canines we know today. Epicyon haydeni were Canidea, and related to our modern dogs. It was roughly twice the size of our modern wolves. It was able to hunt really big prey in the Americas until the big cats moved in. Finally there was competition-and way better competition at that- for Epicyon haydeni, and it allowed for cats to take the prey of this huge dog-like animal, driving it to extinction.
So, dogs could be the size of cats, they’ve just attempted it and failed. In the end, both the Felidae and Canidae families have become the perfect sizes for what they need to do.