That’s why tigers, lions, and your kitty will never have a sweet tooth. In cats, a chance mutation appears to have broken one of these genes, and this broken version persisted. The taste receptor for sweet is encoded in two genes that code for two proteins, both of which are involved in our ability to enjoy sugary treats. Humans, like most other mammals, have five different receptors-salty, bitter, sour, umami (savory), and sweet. Felines’ taste receptors can’t detect sugar. Cat owners may claim that their beloved pets love ice cream and doughnuts, but it’s the fat that cats enjoy. That’s why most mammals experience the taste of sugar as pleasant, but house cats and other felines are indifferent to sweets. Simple sugars taste sweet because we need them (or at least we did before we learned how to artificially produce them in abundance). For most mammals, the ability to detect carbohydrates is a matter of survival. Taste buds have evolved among animal species to lead us toward those things that we need and lead us away from those things we are best off avoiding. It is easy to imagine other species experience the world as we do, be they our pets or even our plants, but the truth is each species has senses adapted for the life it lives, senses that lead it to experience a world different from our own. Some tropical insects evolved without the ability to use the length of days as a cue to the seasons, because in the tropics the seasons are not marked by changes in the length of days. Since the survival of carnivores does not depend on their ability to find sugars, genetic mutations that rendered some of them unable to taste sweetness persisted. Separately, evolution also tends to favor a superior sense of smell and hearing in these same organisms. Animals that evolve underground lifestyles often lose their eyesight. Evolution tends to do away with senses that are not needed, especially if those senses are costly. We take our senses for granted and generally assume that other creatures possess the same ones we do-sight, hearing, smell, taste, or more complex perceptions such as the ability to tell apart the seasons.īut just like other abilities, senses evolve to support the daily functions of animals, plants, and the rest of life.
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