A trekking pole (also known as a hiking pole) is basically a ski pole with a handle that you use when hiking. Trekking poles are almost always used in pairs. There is also something called a hiking staff (also known as a hiking stick) that is a single pole. Most hikers go with two trekking poles over a hiking staff.
a DIAGRAM would be the best option as he can explain each animals food habits. (An image can also be used if he doesn't want to explain, but diagram is better)
