African elephants boast long, sharp tusks. When Asian elephants do have tusks, they are much less developed then those of African elephants. The trunks of African elephants split into two finger like projection at then end, but Asian elephants have trunks with only one such feeler. [Source: Reading for Results Ninth Edition by Laraine Flemming] I think "while" is more appropriate to the context rather then "when." So I was wondering here what meaning "when" has. Thank you in advance for your help.