Whether or not the puma (mountain lion) is a member of the big cat group is a matter for debate and scientists have argued over the subject for years. There’s no question that the puma is a large cat and therefore on size alone should or could be described as a big cat. In fact, on my assessment, the puma is slightly larger than the leopard and the leopard is a big cat – one of four including the tiger, lion and jaguar. However, the category described as “big cats” is not a strictly scientific one. It is somewhat anecdotal and there’s some elasticity in the terminology. That said, the big cats are able to roar and the puma is not able to make that vocalisation which arguably excludes it from the big cat category.
For many years, the puma was included in the small cat group (Felis) before molecular geneticists began to study felid phylogeny (the history of the evolution of a species). This assessment was based upon the shape of the puma’s nose (rhinarium), the morphology of its feet and the shape of its pupils. All of these aspects of its anatomy are similar to those of the small cats.
Further, pumas resemble the smaller cats in that they have a short, wide skull and a short face. This is a reference to the distance from the eyes to the end of the nose. To return to vocalisations, the puma purrs like the smaller cats all the which tends to lead to the puma being left out of the group described as big cats.
I think you will find, however, that some people do place this beautiful wild cat species in the big cat category simply for the reason that it is a large animal. There’s not much more to say about this. It comes down to certain aspects of anatomy.
Capitalise or not?
Dr Desmond Morris in his book Cat World does not venture into the argument as to whether this is a big cat or part of the small cat species.
On a different subject but one which is also apparently unresolved is whether you capitalise the word “Puma” or not when the word is included in a sentence. Dr Morris does captitalise while Mel and Fiona Sunquist the authors of Wildcats of the World do not. I favour not capitalising it and follow the Sunquists. I think that the more modern tendency is not to capitalise.