A dragon in miniature
Gili Motang is a small, 30-square-kilometer island within Indonesia's Komodo National Park. While the park is famous for the Komodo dragon (Varanus komodoensis), the world's largest lizard, the population on Gili Motang is distinct. These dragons are generally smaller than their relatives on the larger islands of Komodo and Rinca. An adult male on Komodo Island can reach 3 meters in length and weigh over 70 kilograms, but the Gili Motang lizards are noticeably smaller, an adaptation to the island's limited resources.
The island's small size and lower elevation create a drier climate compared to its larger neighbors. This environment supports a less abundant prey base. While dragons on Komodo and Rinca hunt large animals like Timor deer and water buffalo, the Gili Motang dragons subsist on a more limited diet. This scarcity of large prey is the main reason for their smaller average size. The entire population is estimated to be fewer than 100 individuals. This small number makes the population particularly susceptible to environmental changes or disease.
An isolated gene pool
Genetic studies reveal the Gili Motang dragons' unique status. Analysis using microsatellite loci shows that this population has low genetic variability and a lack of distinct alleles compared to dragons on Komodo, Rinca, and Flores. This is an example of a small, isolated population experiencing what is known as a founder effect, where a new population is established by a small number of individuals, limiting its genetic diversity from the start.
Whole-genome sequencing further supports this, identifying the Gili Motang population as having the lowest number of single-nucleotide polymorphisms (SNPs) among the islands studied, indicating less genetic variation. There is evidence of very low gene flow between Gili Motang and the other islands. While Komodo dragons are capable swimmers, the distances and currents have been sufficient to keep this population largely isolated. This long-term separation has made the Gili Motang dragon a distinct evolutionary unit. Its genetic dissimilarity is an important part of the species' total biodiversity, holding unique genetic information that is not present in the larger populations. The population's decline, with a growth rate estimated at 0.68, makes its conservation a priority.