During this time, Sheldrick raised and rehabilitated back into the wild community orphans of misfortune from many different wild species, including elephants, black rhinos, buffalo, zebras, elands, kudus, impalas, duikers, reedbuck, dikdiks, warthogs, civets, mongooses and birds. Sheldrick was a recognised authority on the rearing of wild creatures and was the first person to perfect the milk formula and necessary husbandry for both infant milk-dependent elephants and rhinos. When she first made attempts to keep the orphaned baby elephants alive with traditional milk sources, they remained malnourished and faded into death. It was only after trying every combination she could find that she hit on one milk formula from Europe containing coconut oil that was found to be the nearest substitute for the fat in elephant milk.