Common House Gecko, Hemidactylus frenatus

Common House Gecko, Hemidactylus frenatus. Gecko collected from with a residence in the greater Los Cabos area, Baja California Sur, July 2012. Length: 11.5 cm (4.5 inches).

Common House Gecko, Hemidactylus frenatus. Gecko collected from with a residence in the greater Zihuantanejo area, Baja California Sur, July 2012. Length: 11.5 cm (4.5 inches). Photograph taken in Zihuantanejo, Guerrero, March 2019. Photograph courtesy of Ron Woheau, Zihuantanejo. Identifications courtesy of Gary Nafis, Californiaherps.com.

The Common House Gecko, Hemidactylus frenatus, is a largest member of the Gekkonidae family of Geckos. The Gekkonidae family has nine hundred fifty members that have been placed in sixty-four genera. There are one hundred ninety-one global species in the Hemidactylus genus, with a new species being described every few years. The Common House Gecko is known in Mexico as Gecko Casero or Lagartija Besucona.

Common House Geckos vary in color from gray or light brown to beige with a greenish iridescence and off-white undersides. They also sometimes appear to be semi-transparent. They have disproportionately large heads with a long snout and small, roundish ear openings. Their forehead is concave and they have vertical pupils. Their eyes are binocular and have a low convergence ratio with a high visual cell density. These modifications allow them to see well during nighttime hours. Like most lizards, the Common House Gecko has 4 developed legs, a long tail, and a prehensile tongue for catching prey. Their scales are generally uniform anteriorly and increase in size along their back. Their tail is rounded, slightly depressed, and covered dorsally with very small, smooth scales and a longitudinal series of six keeled tubercles. Their tails serve several functions. Male geckos lift their tails and vibrate them briefly to ward off other males. Additionally, their tails provide an energy storage location which the animal uses under abnormal feeding conditions. Common House Geckos have the ability to lose their tails as a defense mechanism to distract predators, which can be regrown. They have enlarged claws and adhesive toe pads that aid in their ability to climb walls and ceilings. Adult geckos grow to be 7.5 cm (3.0 inches) to 15.0 cm (5.9 inches) in length. Sexual dimorphism is displayed with the males growing larger and possessing wider jaws than the females.

In tropical areas, Common House Geckos breed throughout the year, while breeding in cooler climates is more seasonal. Mating involves a short courtship where the male repeatedly touches the female with his snout and may bite or hold her by the neck. Males will give out a distinctive 3 to 5 note call as they approach a female for courtship, and again after mating. Common House Geckos reproduce sexually and are oviparous, meaning they lay eggs that hatch and mature outside of the female’s body. In their native habitat, eggs are produced year round. In colder areas, eggs are not laid in the winter. To protect against predators, eggs are typically laid in cavities, cracks, behind hanging pictures, and other objects on walls such as open light sockets. Their eggs are not cared for by either parent and typically incubate for 46 to 62 days, depending on geographical location. In warmer climates, incubation times tend to be shorter. Females typically lay 2 eggs at a time and in some island populations, human disturbances have resulted in more eggs being laid. Sometimes, the large, white eggs are visible through the female’s clear/white underside. Female geckos can also store sperm for up to a year, an adaptation that likely assists the species’ transportability and invasion success. No post-hatching care is provided to the offspring. The Common House Geckos has a lifespan of five years in the wild.

Common House Geckos are nocturnal, emerging at dusk to forage by climbing walls of houses, hotels, restaurants, and other buildings that have artificial lights. During the day, they hide in some form of shelter. Their most distinctive feature is their frequent and loud vocalizations, best described as ‘chuck, chuck, chuck’. Males use this call for a variety of situations such as emerging from daytime shelters, moving to feeding areas, after feeding, winning a fight with another male, and during and after mating. They are territorial, aggressive, and are known to be cannibalistic. Common House Geckos are generalist predators and will eat virtually any insect or spider they can capture and swallow. In turn, they are preyed upon by birds, cats, dogs, lizards, rats, snakes, and spiders. They are also plagued by parasites such as flukes, protozoans, roundworms, tapeworms, and tongue worms. 

In Mexico the Common House Gecko has been recorded in twenty-one of the thirty-one states, including Socorro Island in the Revillagigedo Archipelago. They are absent from the cooler higher elevations in southern Mexico and the interior deserts of the northern Mexico Plateau. They can be found on boulders, beneath rocks or rotting logs, and on trees. They are most commonly found on buildings in both villages and large urban areas, typically close to electric lights at dusk. Additionally, they occur in a diverse range of natural habitats including rainforests, savannas, and semiarid regions.

The Common House Gecko is very similar to three other gecko species found in Mexico – the the American African House Gecko, Hemidactylus mabouia, the Mediterranean House Gecko, Hemidactylus turcicus) and the Tropical House Gecko, Hemidactylus brooki (all with dark brown mottled coloration).

From a conservation perspective the Common House Gecko is considered to be of Least Concern with an exceptionally wide distribution and high densities in anthropogenic habitats. Currently, no major threats have been identified for this species. Common House Geckos are not a threat to human safety and viewed as beneficial to maintain insect populations. They are, however, deemed to be an environmental pest in some regions. Their continued invasion within naturalized ranges is causing a significant reduction in native gecko populations, especially in urban areas. The Common House Gecko is sold in the pet trade as both a pet and as snake food.