jab1: The equids probably pre-date camels as domesticated animals. It’s a little dicey with the Dromedary Camel, which MAY have been domesticated in Southern Arabia by as early as 4000 B.C.E., but was definitely domesticated by 1800 B.C.E. . The Bactrian Camel was likely domesticated about 2500 B.C.E. in Central Asia.
Camel fun facts ( since I have the book in front of me 
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1.) As of the mid-1980’s there were about 14 million domesticated camels in the world, all but 1.5 million Dromedaries. The largest number are found in the Sudan, Somalia, and India.
2.) Camelus dromedarius is now found only as a domesticated animal, with the exception of about 25,000 feral animals in Australia. Wild populations of Camelus bactrianus were fairly common until about the 1920’s, but now comprise only two small colonies, with about 200 in China and several hundred in Mongolia.
-Tamerlane