dromedary v. Bactrian camel

Dromedary (top) & Bactrian camel (bottom). Lithograph by Carl Brodtmann.

• The dromedary or Arabian camel (Camelus dromedarius) has one hump on its back for fat storage; the Bactrian camel (Camelus bactrianus) has two.
• Dromedaries are found throughout North Africa and the Middle East. There are also several hundred thousand feral dromedaries in Australia. The substantially rarer Bactrian camel is indigenous to northeastern Asia.
• Dromedaries are tall and fast - with a rider, they can run at about 13 km/h for extended periods. Bactrian camels are stocky and slower, averaging about 4 km/h when loaded.
• Dromedaries were domesticated between 4000 and 2000 BC; Bactrians were domesticated around 2500 BC.
• To adapt to the large annual temperature range in the Gobi Desert, Bactrian camels grow a thick coat of hair each winter and shed it in the spring. Dromedary camel coats remain the same length year-round. 

The Hatch Report on dromedary v. Bactrian camels