People often contact me about Chausies, expecting them to be huge. They are not. They are a domestic breed and fall within the size and weight range of other domestic cats.
Take a look at the chart below. It compares the typical weight and height at the shoulder of three nondomestic species, and compares it with the regular domestic cat.
Okay, now remember, the serval is the ancestor of the Savannah breed.
The Asian Leopard Cat is the ancestor of the Bengal breed.
Felis chaus is the ancestor of the Chausie breed.
In developing the Savannah, the Bengal, and the Chausie, breeders used a great many regular domestic cats and just a few nondomestic foundation cats. They used selective breeding to try to create breeds that looked as much like their respective ancestors as possible. However, most of the ancestors of the three breeds have been regular domestic cats.
What you see here is that the serval is by far the largest of the nondomestic species used. It is nearly twice as tall as the other three species, and it is 50% or more heavier than the other species.
On average, Felis chaus is somewhat taller and heavier than the domestic cat, but it overlaps a lot in size with the domestic cat. Once you start breeding Felis chaus to the domestic cat, the size difference mostly disappears. That's what one would expect, and that is exactly what we have seen.
Even Felis chaus itself is NOT all that large. Notice that it can be as small as 9 pounds, particularly in places like India. It is the look of the cat that makes it interesting, and it's the personality that matters most of all. It's the magical way that Chausies interact with people and the interesting things they do, most of all, that make them wonderful companions.
If you want a BIG cat, you can try looking for a Savannah. However, even the Savannahs are not usually any larger than a large domestic cat such as the Maine Coon. That's because it takes between 5 and 8 generations of outcrossing to domestic cats before Savannahs become reliably fertile, and they are not technically part of the domestic breed until they are fully interfertile.
For people who want a huge cat, the only reliable option is to obtain a first or second generation serval-domestic hybrid. (They are registered as Savannahs, but they are not actually Savannahs in those first two generations, and usually the people who specialize in breeding the hybrids are not the same people who breed genuine domestic Savannahs.)
Also, if you want a huge cat, you need to get a male. The females of all these species and breeds are quite a bit smaller than the males.
Back to Chausies, I cannot emphasize strongly enough. You don't buy or adopt Chausies to get a huge cat. You bring one into your life because they are great companions, fascinating fur persons, and pretty nice looking, too. They have an amazing history, genes we are still learning about, and more. But, no, they are not big. You can always find people on the internet* who will make claims, but reputable breeders will tell you the truth.
Bibliography (work in progress):
*In particular, television programs and their websites are extremely unreliable sources of information about animals, including cats. All they care about is entertainment for the masses.