Geckos are small lizards that can be found in warm climates around the world. One of the most widespread and familiar geckos is the common house gecko, also known as the Asian house gecko or Pacific house gecko. This adaptable little reptile lives alongside humans in homes and buildings in many tropical and subtropical regions.
Description of the Common House Gecko
The common house gecko is a small, lightweight lizard, usually 4-6 inches (10-15 cm) long from snout to vent. Their tails are typically the same length as their bodies. Their toe pads have sticky lamellae that allow them to climb vertical and inverted surfaces with ease. They have large eyes with vertical pupils, lidless eyes with a clear membrane that protects their eyes and helps keep them clean.
House geckos are gray, brown or tan in color with darker spots, blotches or bands. These markings help them camouflage against tree bark and other surfaces. Their skin is covered in small granular scales. They do not have moveable eyelids, so they lick their eyes to keep them clean and moist.
One of the most distinguishing features of house geckos is their vocalizations. The males make loud clicking or barking sounds during mating season. These vocalizations advertise territory and attract females. Their scientific name, Hemidactylus frenatus, comes from the Greek words for “half finger” (hemidaktylos) and “rein” or “bridle” (frenatus), referring to the lamellae on their toes that resemble half-fingers.
Native Range and Habitat
The native range of the common house gecko extends from Southeast Asia to Polynesia and parts of Africa. This includes countries like Thailand, Vietnam, Philippines, Indonesia, Papua New Guinea and more. They inhabit tropical forests, limestone cliffs, mangroves, and human dwellings.
House geckos are commensal species, meaning they share their habitat with humans. They thrive around human habitations where food and shelter are abundant. They are often found on or inside houses, sheds, garages and other manmade structures. Their ability to climb smooth vertical surfaces allows them to inhabit walls, ceilings, furniture and more.
Introduction Around the World
From their native range, house geckos have spread around the world through accidental transportation via cargo shipments and other human activities. They are now found in subtropical and tropical regions globally including:
- North, Central and South America
- Caribbean islands
- West Africa
- Madagascar
- Arabian Peninsula
- South and East Asia
- Australia
- Pacific Islands
The common house gecko adapts readily to new environments. Their populations can grow and spread quickly in suitable habitats thanks to rapid reproduction. Females can produce up to six clutches of one or two eggs every year.
Size and Growth
When they hatch, house geckos are around 1.5-2 inches (4-5 cm) in total length. They reach adult size in under a year. Maximum size depends on food availability, population density, temperature and other factors.
In typical conditions, common house geckos grow to around 4-6 inches (10-15 cm) in length from snout to vent. Their tails are usually about the same length as their bodies. Some large specimens may reach up to 8 inches (20 cm) in total length including the tail.
| Size Category | Snout-Vent Length | Total Length (with tail) |
|---|---|---|
| Newly Hatched | 1.5-2 inches (4-5 cm) | 3-4 inches (8-10 cm) |
| Typical Adult | 4-6 inches (10-15 cm) | 8-12 inches (20-30 cm) |
| Large Adult | Up to 8 inches (20 cm) | Up to 16 inches (40 cm) |
The largest house geckos tend to come from populations on small islands where food is abundant and competition is low. For example, Tokelau Islands house geckos reportedly reach 8.5 inches (21.5 cm) long from snout to vent.
Maximum Size Records
According to most sources, the largest verifiable total length for a common house gecko is 11.8 inches (30 cm). This includes a snout-to-vent length of 7.9 inches (20 cm) plus a 4 inch (10 cm) tail.
This record was set in 2010 by a house gecko captured on Suluan Island in the Philippines by ecologist Perry Ong. The Suluan Island population was introduced in the 1960s or 70s and became unusually large due to lack of predators and competition.
Other unverified reports suggest house geckos may exceptionally reach up to 13 inches (33 cm) in length. However, these extremes tend to be isolated cases from small island populations.
In typical environments with more competition and predation, house geckos average 6-8 inches (15-20 cm) total length as adults. The largest common length appears to be around 10 inches (25 cm) including the tail.
Differences Between Males and Females
Male and female house geckos are similar in appearance. The main differences are:
- Males tend to be slightly larger than females.
- Males have broader heads and necks.
- Males have bulges at the base of the tail that contain hemipenes.
- Females have thinner tails.
However, these differences are subtle and house geckos’ sex can only be determined reliably by checking for hemipenes (males) or eggs (females).
Common House Gecko Lifespan
Common house geckos are short-lived compared to many other reptiles. Their typical lifespan in the wild is estimated at:
- 1-2 years for wild geckos.
- 3-5 years for geckos in captivity.
With optimal care and conditions, house geckos may live up to 7-10 years in captivity. But anything over 5 years is uncommon.
House geckos have high mortality rates in the wild due to predation and environmental pressures. Most do not survive to their full potential lifespan. Their breeding strategy favors producing many offspring to compensate for short individual lifespans.
Taxonomy and Classification
Here is the scientific classification and taxonomy of the common house gecko:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Reptilia
- Order: Squamata
- Suborder: Lacertilia
- Infraorder: Gekkota
- Family: Gekkonidae
- Genus: Hemidactylus
- Species: Hemidactylus frenatus
This species was first described by the German zoologist Johann Georg Wagler in 1836 as Hemidactylus frenatus. No subspecies are currently recognized.
Diets and Hunting
House geckos are insectivores that feed on a variety of small prey including:
- Insects – crickets, grasshoppers, moths, roaches, flies
- Spiders
- Scorpions
- Centipedes
- Millipedes
- Smaller lizards
They are nocturnal hunters that wait patiently to ambush prey that comes within reach. When an insect approaches, they quickly lunge forward, grasp it in their jaws, and swallow it whole.
House geckos play an important role in controlling pest populations like mosquitoes, cockroaches and spiders around human homes. Their specialized toe pads allow them to hunt in areas most predators can’t access.
Defense and Camouflage
House geckos rely on stealth and camouflage to avoid predators. Their mottled coloration lets them blend in against bark, rocks and human-made structures. They can flatten their bodies in narrow crevices to hide.
If threatened, their first response is to flee quickly out of sight. They can detach their tails through caudal autotomy as a distraction if grasped. The tail continues to wiggle vigorously for a time after separating, allowing the gecko to escape.
House geckos vocalize distress calls when bothered by predators. They may also open their mouths wide or inflate their bodies to appear more threatening.
Reproduction and Life Cycle
House geckos reach sexual maturity around 8-10 months old. Breeding occurs year-round in warm climates. The peak breeding season is typically spring and summer.
Like other geckos, house geckos are oviparous – they lay eggs rather than giving live birth. Females lay pairs of eggs every 3-4 weeks and can produce up to 6 clutches per year.
The eggs are small, white, elliptical and have flexible shells. Females often adhere them to vertical surfaces like walls and cliffs. The eggs incubate for 30-60 days before hatching.
Baby geckos emerge fully developed and ready to hunt. They reach adult size in under a year. House geckos live 1-2 years on average in the wild.
Adaptations
House geckos have many specialized adaptations that allow them to thrive around humans, including:
- Sticky toe pads – Allow them to climb smooth vertical surfaces.
- Excellent camouflage – Lets them hide against bark, rocks and walls.
- Nocturnal habits – Avoid daytime predators.
- Vocalizations – Communicate for mating and territorial defense.
- Caudal autotomy – Detach tail to escape predators.
- Rapid reproduction – Produce many offspring each year.
- Generalist diet – Feed on many types of small prey.
Interactions with Humans
The close relationship between house geckos and humans is mainly commensal – benefiting the geckos while having little positive or negative effect on people. These adaptable lizards live in and around human homes searching for insect prey that congregate near artificial lights.
Most people tolerate or even welcome house geckos because they help control pest populations. Their small size and non-threatening nature makes them unobtrusive housemates. They are mild-tempered and unlikely to bite unless severely provoked.
Some people dislike having wild geckos in their living spaces or confuse them with snake-like reptiles. But household sprays and removing their food sources are usually sufficient for controlling unwanted populations. Their spread to tropical regions worldwide illustrates their highly commensal nature.
Conservation Status
The common house gecko has an extremely large global population and range. They readily adapt to disturbed habitats and thrive in close association with human settlements. For these reasons, they are evaluated as Least Concern on the IUCN Red List of Threatened Species.
Introduced house geckos are considered invasive in Hawaii and some other locations. They compete for resources with native species and their populations sometimes need to be controlled. But in most of their introduced range they are benign or even beneficial commensals.
Conclusion
In summary, the common house gecko is a tiny reptile measuring around 4-6 inches long on average, or up to about 10 inches total length at the largest. Through rapid reproduction and commensal adaptations, house geckos have spread from their Asian origins to live in tropical habitats around the world alongside humans.
