Is it necessary to know the type of meat (such as camel) when eating it in order to perform ablution from it before prayer?

There is no obligation for someone who has eaten meat to investigate whether it was camel meat or not. However, if it becomes clear to the person performing ablution that they have eaten camel meat, then their ablution is invalidated according to the Hanbalis, contrary to the view of the majority.

The Hanbalis have explicitly stated that eating camel meat, whether raw or cooked, invalidates ablution, citing as evidence the hadith of Al-Bara' bin 'Azib and Jabir bin Samurah.