What compels them to open up their shells ... Come nightfall, the giant clam closes its shell. The mantle on its shell also contains two holes, the inhalant and exhalant siphon.

What's inside a clam ... And that shell comes in all different sizes. There are small clams, like these, which are often used for cooking. And then there are giant clams, which can grow more ...

The PCG said this was the biggest illegal giant clam shell haul in the region's history to date. The suspects are Rey Cuyos, 54; Rodolfo Rabesa, 48; Julius Molejoa, 47; and Erwin Miagao ...