This is one of the few formal studies involving both caffeine and camels:
“The Pharmacokinetics, Metabolism and Urinary Detection Time of Caffeine in Camels,” I.A. WASFI, N.S. Boni, M. Elghazali, A.A. Abdel Hadi, A.M. Almuhrami, I.M. Barezaig, and N.A. Alkatheeri, Research in Veterinary Science, vol. 69, no. 1, August 2000, pp. 69–74, DOI 10.1053/rvsc.2000.0389. [AIR 15:6] The authors, at Camel Racing Laboratory, Forensic Science Laboratory in Abu Dhabi, United Arab Emirates, report:
“The pharmacokinetics of caffeine were determined in 10 camels after an intravenous dose of 2·35 mg kg–1…. Caffeine could be detected in the urine for 14 days.”