Kisar covers an area of only about 80 square kilometers (30 square miles) but the researchers found more than 30 rock art sites and hundreds of individual rock paintings in limestone terraces on the island.
The researchers made two expeditions to Kisar in 2014 and 2015, originally to look for signs of early human occupation.
The islands have been inhabited for thousands of years, but a wave of new settlers about 3500 years ago brought agriculture to the region.
They were astonished at the richness of the prehistoric rock art that they found – at least 30 rock art sites have been discovered on Kisar so far.
An ocean view
The rock art sites often look out over the coastline, a few hundred meters (yards) away.
Evidence of humanity
These rock paintings from the Here Sorot Entapa site (top, a & b) and from the Jawalang 6 site (bottom, c) show human figures in boats.
Dogs appear in some of the rock paintings, which means they were painted some time after dogs were introduced to the region about 3500 years ago.
The researchers think these hand stencils may be much older than the figurative paintings.
Others rock painting appear to show human figures in procession, carrying axes and shields.
Lead archaeologist Sue O’Connor thinks the figurative rock paintings on Kisar were made about 2500 years ago, when a new style of rock art began to be made at many islands in the region, including nearby Timor.
The drums – known as Dong Son drums after the site of their first discovery in Vietnam – were traded throughout Southeast Asia during the Bronze Age.
Similar patterns are a common feature of the rock art on Kisar and Timor.
They may indicate the sun itself, or perhaps the patterns on particular drums that signified different tribal groups.
Effects of trade
She says that Bronze Age prestige items, such as Dong Son drums, may have been traded for rare spices such as nutmeg, mace and cloves, which were once found only on these islands.