According to Australian scientists, horses and many other large mammals have long snouts simply because they can afford to. This question is quite significant in the study of mammalian evolution. After all, long-snouted mammals don’t appear by chance. More often than not, a longer snout coincides with a larger body size in certain groups of animals. Researchers refer to this phenomenon as the “craniofacial evolutionary allometry” (CREA) effect. It can be observed in various groups of mammals, such as cats, rodents, deer, kangaroos, and some monkeys. CREA is also evident when comparing the snouts of a sheep and a cow or a small deer and a large moose. A team of researchers from Flinders University and the University of Adelaide noted that the CREA effect is quite widespread. However, science has yet to fully explain it. One hypothesis suggests that the CREA pattern may be an innate feature of skull development, where a mammal’s face automatically becomes longer as the animal grows. Yet, there’s a problem with this explanation: in many cases, the CREA pattern does not exist. Tasmanian devils, sea otters, and orcas are bulkier than most of their relatives, but they have shorter faces. Meanwhile, honey possums and nectar-feeding bats, despite their small size, have long snouts. Clearly, a large body size does not always mean that a mammal’s face should be long, as reported by Science Alert.
So why is the CREA effect so prevalent? Researchers suggested that the answer lies in the simple biomechanics of how species use their snouts for feeding. The scientists pointed out that related animals typically consume similar foods. For instance, sheep eat the same grass as cows. However, sheep are smaller, so they have to work harder with their jaw muscles and teeth (which make up a larger portion of their snouts). It turns out that the shorter snouts allow for more efficient biting due to the reduced distance between the jaw muscles and teeth. It’s similar to how barbecue tongs work: the closer your hand is to the tips, the stronger your grip on the steak.
This raises a logical question. If animals with shorter snouts are such skilled eaters, why do larger mammals still have longer snouts? Scientists hypothesized that larger animals naturally have bigger muscles and therefore bite better. They exert less effort compared to smaller mammals. In other words, larger mammals can afford to have longer skulls, which benefits them in various situations. For example, they can more easily reach leaves from trees or take larger bites.