Vertebrate nutritional ecology is the study of the interrelationships between food resources in the environment and the consumptive use of these food resources by vertebrate animals. Consumptive use includes how vertebrate animals procure, digest, absorb and metabolise available foods in the environment to satisfy their requirements for health, growth and reproduction. The challenge for wild vertebrates is to satisfy their nutritional requirements in an environment that often varies in food availability and quality. Vertebrate animals have evolved a diverse and interesting suite of solutions to the problem(s) of acquiring necessary nutrients and energy in a world where food often does not want to be eaten.

Key Concepts:

• Vertebrates require certain amounts of energy, protein, as well as about 38 micronutrients including 10 essential amino acids, 1–3 essential fatty acids, 13 vitamins and at least 14 essential minerals.
  
• Energy requirements (kJ day^–1) of vertebrates increase with body mass of the animal in a predictable allometric manner (slope»0.72), although birds on average have higher energy requirements for a given body size than mammals.
  
• Protein requirements of vertebrates depend on protein quality (i.e. amino acid composition of dietary protein) because animals require a balanced profile of essential amino acids relative to their needs so that normal rates of protein synthesis are maintained.
  
• Vertebrate animals can grow normally on a diet without carbohydrates provided they consume adequate fats that include the few essential fatty acids.
  
• Bill morphology in birds, and tooth and jaw structure in all other vertebrate classes are impressively diverse and provide excellent examples of evolutionary design in relation to procuring food.
  
• The chemical breakdown of ingested food involves specific enzymes that digest each of the three major types of macronutrients: proteases for digestion of protein, carbohydrases for digestion of carbohydrates and lipases for digestion of fats.
  
• Absorption of digested macronutrients and micronutrients by the intestine involves several processes including passive diffusion, facilitated diffusion and active transport.
  
• Changes in specific activity of digestive enzymes and the absorption rate of digested nutrients by the intestine in response to diet changes provide strong evidence for adaptive modulation of digestive features.
  
• The evolution of enlarged portions of the gut to house symbiotic microbes was crucial in the radiation of herbivorous vertebrates because it provided the appropriate conditions for microbial fermentation to have significant nutritional benefits.
  
• Contemporary research is providing new insights into the importance of phenotypic plasticity and flexibility in the metabolism, physiology and behaviour of wild animals and how this influences an animal's ability to satisfy its nutritional needs in their natural environment.