http://en.wikipedia.org/wiki/Bactrian_camel#Evolutionary_history,
http://en.wikipedia.org/wiki/Camel#Biology
http://www.cbc.ca/news/canada/ottawa/story/2013/03/05/sci-arctic-camel.html
http://www.bbc.co.uk/news/science-environment-21673940
http://ca.news.yahoo.com/blogs/geekquinox/giant-ancient-camels-once-lived-canada-high-arctic-215753079.html
http://www.livescience.com/27639-camel-fossil-found-in-arctic.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Livesciencecom+(LiveScience.com+Science+Headline+Feed)
http://en.wikipedia.org/wiki/Australian_feral_camel
http://www.livescience.com/13670-25-amazing-ancient-beasts-dinosaurs-reptiles.html