These are working places, not petting zoos. The animals here live on the properties year round and the people leading you around are the ones who feed them. That shapes the visit: hours follow the animals rather than the other way round, and summer moves things to the cool end of the day.
Tour, then chill as the desert cools
Run by Kaleidoscope Desert, in Morongo Valley, CA, $95 per person, 2h, up to 8 guests.
An evening guided walk through the sanctuary as the desert cools, then a swim in the pool to wind down. Drinks and snacks from the shop are included, and you can round out the night with the Gamelatron sound experience.
Books on the operator's own website.
It depends entirely on the operator and it is stated on each listing. Some are built for families and some are adults only. Read the age line on the page before you book.
Sometimes, and always on the operator's terms. These are rescues with their own histories and the people who care for them decide what is fair to ask of them on a given day.
Morning and evening, especially from June to September. Animals rest through the heat and so should you, so operators run the cool ends of the day in summer.