Mourning geckos originate from the Marshall Islands in the central Pacific Ocean. Genetic and protein analyses point to this remote chain of coral atolls as the species’ most likely geographic starting point, with the earliest recorded populations found there and on the adjacent Tarawa atoll. From that origin, they have spread across a vast stretch of the tropics, colonizing islands throughout the Pacific and Indian Oceans, Southeast Asia, Australia, and Papua New Guinea.
Native Range in the Pacific
The genus Lepidodactylus includes 34 species of geckos native to Southeast Asia and the Pacific. Mourning geckos are the most widespread of them all, found on countless tropical and subtropical islands. Their native range centers on the Pacific islands, stretching from Micronesia and Melanesia through Polynesia, with populations confirmed across Southeast Asia and parts of coastal Australia. They thrive in rainforest environments, particularly in tropical lagoons and coastal areas where warm, humid conditions persist year-round.
Within their native range, where both sexual and asexual populations exist, the two types occupy slightly different niches. Sexual populations tend to cluster around tropical lagoons and urban centers on islands, while the all-female asexual populations spread more evenly across available habitats.
How They Spread So Far
Two traits make mourning geckos extraordinary colonizers: their eggs can survive saltwater exposure, and a single gecko can start an entire population on her own.
Gecko eggs with rigid shells tolerate seawater remarkably well, whether fully submerged or just surrounded by saltwater spray. Lab experiments on related gecko species show that hard-shelled eggs maintain healthy hatch rates even after prolonged contact with seawater. This means eggs clinging to driftwood, vegetation mats, or floating debris can survive ocean crossings between islands. Natural rafting on storm debris has likely been carrying gecko eggs across open water for thousands of years.
Human activity accelerated the process dramatically. Mourning geckos are tiny, roughly 8 to 10 centimeters long, and easily stow away in cargo, building materials, and plant shipments. They likely reached Hawaii with the first Polynesian voyaging canoes, making them one of the earliest reptile introductions to the archipelago. They remain common across the Hawaiian Islands today, found in national parks and residential areas alike. More recently, global shipping has carried them to the Caribbean, where an established population was first documented in Cuba around 2008. They have since been recorded on islands including the Bahamas, Grand Cayman, and Curaçao. Panama had records as early as 1916, shortly after the Panama Canal opened.
Reproduction Without Males
The trait that truly explains the mourning gecko’s global success is parthenogenesis. Females produce offspring that are genetic copies of themselves, no male required. This means a single egg or a single gecko arriving on a new island can establish a breeding population. Most other lizards need at least a male and female pair to colonize new territory, a much less likely event.
Mourning geckos are obligate parthenogens, meaning they reproduce exclusively this way. Males exist but are extremely rare. The species itself arose from hybridization between two or more ancestral gecko species, and that hybrid origin is what locked in their all-female reproductive mode. Their eggs go through a modified form of cell division where chromosomes duplicate before dividing, ensuring each egg ends up with a full set of genetic material identical to the mother’s.
A Complex of Clonal Lineages
Not all mourning geckos are genetically identical. The species is actually a complex of distinct clonal lineages, some with two sets of chromosomes (diploid) and others with three (triploid). These different lineages arose from separate hybridization events involving different parent species. Researchers have identified that at least three different ancestral gecko populations contributed to the triploid lineages, including a species called Lepidodactylus moestus and at least two other species that haven’t been definitively identified.
Each clonal lineage has a uniform genetic fingerprint within its group but differs from other lineages. Different clones can sometimes be found living side by side on the same island, occupying slightly different microhabitats. This diversity within an all-female species is part of what makes mourning geckos so resilient. If one lineage struggles in a particular environment, another clone may fill the gap.
Where They Live Today
Mourning geckos now occupy one of the largest ranges of any lizard species. Confirmed populations span from islands in the Indian Ocean through Southeast Asia, across the entire tropical Pacific, into Hawaii, and increasingly throughout the Caribbean and Central America. They are considered invasive in many of these locations, continuously expanding their geographic range as global trade moves cargo between tropical ports.
They are nocturnal, small, and remarkably adaptable. In both their native and introduced ranges, they inhabit everything from undisturbed coastal rainforest to the walls of houses and garden sheds. Their small size, sticky toe pads, and ability to glue their hard-shelled eggs to almost any surface make them perfectly suited to hitch rides on human infrastructure. Combined with their ability to clone themselves, it is easy to see why a gecko that started on a few Pacific atolls now lives on islands across half the globe.