Why do our pets eat what they eat?
Diet is one of the trickier aspects of owning a pet. It makes things more difficult when, to our knowledge, they can't tell us specifically what they want or need. Whether it's food that consistently whets their appetite, weight management, allergy control, we are here to shed some light on why our pets eat what they eat.
Biology - The basis for nutritional research
One of the major areas where dogs and cats differ is obviously biology. Simply put, they are different species with different evolutionary histories. Cats are defined as true carnivores, because they need meat to survive. Cats cannot use plant protein for amino acid profiles, so they cannot be vegetarian. A process called gluconeogenesis creates a metabolic pathway for cats to digest and take nutrients from primarily proteins and non-carbohydrates. Without protein from meat, a cat's body will begin to energize itself off it's own muscle - not something anybody wants! Cats also need taurine, an amino acid found in animal tissue, and a moisture high diet due to evolving from desert ancestors. They typically have a low drive for thirst and get most of their hydration from their meat.
Dogs are defined as scavenging carnivores. If you're a dog owner, you've seen this in action - your dog scarfs an unidentifiable piece of grossness down before you have a chance to take it from them. It happens. Many dogs are omnivores, meaning that they can survive on plant matter (read: just about anything). However, as we get into the similarities further on, we can tell clearly that dogs have been 'designed' to eat meat as well.
Physical Characteristics - Similarities between species
Carnassial Teeth: These teeth are the molars and premolars of carnivores and their primary function is to sheer meat off of bone. Large canines are actually NOT an indicator of a carnivore - many animals have large canines who eat almost exclusively plants, such as gorillas!
No production of Salivary Amylase: For humans digestion begins in the mouth as we chew. Salivary amylase is an enzyme responsible for breaking down carbs. Dogs and cats generally eat by swallowing large chunks of meat quickly and do not produce this enzyme. This means the pancreas is solely responsible for processing carbs which can lead to it overworking if there are too many in the diet.
Short, highly acidic digestive tracts: Proteins and fats are digested very efficiently thanks to acidity, which also combats bacteria. A short digestive tract processes raw meat as quickly as possible, not allowing it to fester and therefore combats parasites. The more plants you eat the longer, more complicated digestive system you need - like a cow!
In Summary
Dogs have more flexible digestive needs and can scavenge for missing pieces, letting their body work to create their own taurine and build a complete amino acid profile. Cats can't utilize plant protein, so they need taurine, vitamin A, more thiamine, and a moisture rich diet - all of which comes from animal protein!