🥣 Nutrition & Feeding · 7 min
Principles of captive diets
Why this matters
The most important thing about a diet is whether the animal will actually eat it. Everything else is downstream of that.
By the end of this lesson you will be able to
- Build a captive diet from an animal's wild diet
- Apply the calcium to phosphorus rule and explain metabolic bone disease
- Identify unsafe food sources
Once you know what an animal eats in the wild, crafting a captive diet is conceptually not hard. Predators eat smaller animals, so feed them small, whole animals. Captive rabbits and rodents can be fed foods designed for domestic rabbits or laboratory animals, with vegetables as a supplement, not the sole food. Good quality alfalfa hay is excellent nutrition, but never use it if it smells musty or moldy.
Adults are usually easier to feed than babies: they already have their food-finding skills, they are not growing rapidly, and they are in captivity only briefly, so minor nutritional imbalances matter less. Animals in captivity are often sick or stressed, so you may need to call more experienced rehabilitators to learn what stimuli get a particular species eating.
Where prey comes from
It is generally a bad idea to feed road-killed animals to predators. First, it is illegal to pick up road-kill without a special license from NYSDEC. Second, such animals may be sick or heavily parasitized and pass that along. Laboratory rodents can be purchased online and stored in a separate freezer.
Calcium and phosphorus
Beyond calories, animals need enough calcium and phosphorus in a ratio of about 2 parts calcium to 1 part phosphorus. An imbalance causes metabolic bone disease, a serious and usually irreversible malformation of the skeleton. Young, rapidly growing animals are the most sensitive, which is exactly the population most rehabilitators handle. Vitamin supplements benefit growth and development.
Specific supplements
- Frozen fish must be thawed carefully in the refrigerator and supplemented with vitamin E and thiamine (vitamin B1) to prevent deficiencies.
- Herbivorous reptiles may need calcium supplementation if housed long term.
- Assess caloric adequacy by weighing the animal regularly, not by watching the bowl.
This lesson is part of the NY Wildlife Rehabilitator Exam course. Open it in the course to answer the retrieval checks that go with it, track what you have read, and quiz the whole unit. Lessons, quizzes and the glossary are free.