Thank you for the links and comments. I realize the diets vary widely, I'm just looking for starting points. I've been working on a project for quite a while now on ways to help increase zoos economical and environmental standing by providing at least a portion of their dietary needs on zoo grounds. Either through dedicated gardens / fields or - more likely in facilities with limited means and space - replacing their existing decorative foliage with edible versions that look decorative, but also provide forage, herbs, veggies, etc. My goal is to increase my study to a 10-30% production rate for each species (depending on needs) where their diet or enrichment includes foliage, insects or fish. This would buffer their need for donations (albeit in a limited manner), while increasing the nutritional value of the animals food and possibly expanding their ability to be fed a diet closer to their natural ones. It would also open educational opportunities to guests. I've done the research on permaculture and hiding 'normal' plants in decorative beds. Hydroponics, aquaponics, etc, etc... But to calculate the percentages, I need to know which animals are capable of eating which things. And to what extent that is feasible.
For example, I know that an adult male lowland gorilla eats 40-45 lbs of food per day. Of that, 4% is root vegetables, 7% fruit, 15% high-fiber primate biscuit, 17% vegetable, and 57% leafy green vegetables. So I can extrapolate that a single male gorilla eats (on avg), 1.8 lbs of root veggies, 3 lbs of fruit, 6.75 lbs of biscuits, 7.65 lbs of veggies, and 25.65 lbs of leafy greens.
- Leafy greens take a lot less room to grow than root vegetables. So a zoo short on space would benefit more from concentrating on supplying their own leafy greens while purchasing the root veggies. Especially if they had edible tree and forage species where they didn't need dedicated growing areas but just fed the trimmings. But some species are poisonous to some animals and not others. So if you were to grow root veggies, yams would be better than potatoes, because potato vines are poisonous, while yams; one animal could eat the vines and another could eat the vegetable. This is where needing to know which things each animal can eat comes in.
Sorry about the long windedness, but my point being... To make this proposal applicable to zoos in general, I would need to tailor the pitch to each zoo. What I would like to do, is say something like "You have 1 giraffe? 1,033 combined sq feet will give you all the veggie requirements you need per year on the current diet. If you reach out to the people posting that they have a crab apple and don't like the apples, point out that if they donate that one trees harvest that is a years supply for your one giraffe. Or If you install a crop box or something similar, it will take 8'x40' (320 sq'). It will provide enough fodder for all 3 of your elephants."
I started out as just an "I'm bored" moment while playing a zoo game. To make it realistic started doing the math and incorporating it into the game. I was quite surprised how little area you actually need (in real life) to feed each one of those zoo animals individually. Obviously, 100% isn't feasible for most zoos. But 10-30%? So I'm curious what the requirements for other animals are. I'd like to possibly reach out to my local zoo about it once I get more data on it.