The performers strike each others sticks in the course of the choreography. Membranophones are not very common, though the hourglass single-headed drum like those played in Papua New Guinea is found as far north as the Marshall Islands. In keeping with the ecology of atoll life, the skins of these drums are made from a shark's belly or parts of the sting ray. Many atolls of the Micronesian Pacific are without any indigenous musical instruments whatsoever. As you head east into Polynesia from Melanesia, the Melanesian flutes disappear and the instruments become more sparse, but the passion of the music becomes greater - particular the harmonic content which comes straight from the heart.
Music is a reflection of topography and people reflect the landscape they are living in.
It is must be remembered that these people came to these islands by canoe and only carried what they needed to make the voyage. When they arrived at their destination, there often were no wood or material to make instruments. The canoes were considered sacred, so no effort was made to break them up to make a musical instrument. The shells used for a trumpet include the conch and triton.