Bactrian camel
In 1975, Richard Bulliet of Columbia University wrote that the dromedary exists in large numbers in areas from which the Bactrian camel has disappeared; the converse is also true to a great extent. He said this substitution could have taken place because of the heavy dependence on the milk, meat and wool of the dromedary by Syrian and Arabian nomads, while the Asiatic people domesticated the Bactrian camel but did not have to depend upon its products.