The question in the title is malformed. It is inaccurate but I have taken it direct from quora.com. For a start, the caracal and serval are not small cats. They are medium-sized wild cats. Also, a genuinely small cat which happens to be a cute-looking wild cat, the sand cat, has enormous and round ears. And the cheetah has rounded ears. These factors alone undermine the question.
In answering the question, we have to forget about small and large cats and address how they hunt instead which is the relevant influence on anatomy. For instance, the serval relies tremendously on hearing to detect small prey animals such as rodents in long grass. They attack and kill prey by leaping up in the air and locating the prey by sound alone. They need large ear flaps to achieve success.
Regarding ear flaps (auricula) being pointed, perhaps it is far to say that when ears are larger and therefore taller they naturally tend to come to a point.
The sand cat also relies on detecting prey by sound and their ears are on the side of their head to make them inconspicuous in open, sandy environments as they are the only true desert cat. Sand cat – comprehensive page (2022)
The caracal had larger ears in relation to body size than the big cats, it is true. And they are large with black lynx tips. In general cats rely on excellent hearing to detect prey and therefore the size of the caracal’s ears are no surprise. The large ears don’t make them more visible in open ground which they like because their coat is good camouflage and the black lynx tips to the ears act as disruptors to their outline it is believed. They hide very effectively when lying down in open terrain.
Also, although anecdotal the large ears and lynx tips may be used as form of communication with other caracals. Also, caracals are known to favour birds as prey and catch them as they take flight. The caracal may depend on better than normal hearing to approach birds without detection. The ears are pointed but the lyns tips exaggerate this feature. And I’ll stick to my arguement above about large ears being pointed.
The domestic cat has medium-sized ears for felines if we are referring to the moggie which evolved through natural selection. Some breeds such as the Maine Coon have very large, pointed ears (and the Oriental) because of artificial breeding. The ears are unnaturally large and are for appearance only. The ear flaps of the moggie are relatively large in relation to body size compared to humans for instance as cats rely on hearing far more than humans.
The tiger has smaller and more rounded ears relative to body size than some cats but they are not small per se. They are effective enough and the tiger relies less on hearing and arguably relies more on visuals when compared to, for instance, the serval and sand cat. The same goes for the lion which inhabits open ground where it can see prey. One factor here might be streamlining as suggest below to make the cat and more effective dasher when attaching prey.
The cheetah also has relatively small ears in comparison to body size compared to the caracal but they are not small per se and they are rounded. This large wild cat relies on speed to catch prey. They rely less on hearing to detect prey and more on what they see and they live in open habitats so they can utilize their extraordinary speed to track down prey over a maximum of 400 yards before they overheat and have to stop.
What and AI computer says
An artificial intelligence computer has a different opinion to me in some respects. It firstly says that the shape of a cat’s ears is believed to be related to their hunting habits. I agree that because I’ve said the same thing above but in more detail.
Domestic cats, caracals and servals are ambush predators. They rely on stealth and camouflage to catch prey. They argue that there pointed ears help them to do this by keeping their silhouette low and compact. That does not make sense to me because large pointed ears are not going to result in an inconspicuous silhouette.
They do add, correctly, that the big cats such as lions, tigers and cheetahs are primarily chased predators. The latter two species, lions and cheetahs, as mentioned, live in open territory but the tiger lives more in woodlands and forests therefore rely more on stealth. There interesting camouflage which doesn’t look like camouflage at all, is actually very effective for the kind of habitat in which they live.
But these cats rely on speed and agility to catch their prey. Rather extraordinary, the AI computer says that their rounded ears help them to run faster because they reduce drag. I’m not sure this is correct but it might be.
But clearly the ears have an adaptive function based upon survival which in turn is based upon the cat’s effectiveness in catching prey. That’s what it boils down to at the end of the day. This is the process of evolution as described by Charles Darwin. A cat evolves an anatomy which improves their chances of survival and this evolutionary process happens over a million or more years.
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