Gecko Characteristics
Geckos are a type of lizard found all over the world. There are over 1,500 species of geckos, making them one of the most diverse groups of lizards. Geckos come in a huge range of colors, patterns, and sizes. The smallest gecko species is less than 2 inches long, while the largest can reach up to 28 inches in length.
Despite this diversity, geckos share some common physical characteristics that set them apart from other lizards:
- Large eyes with vertical pupils
- Lack of eyelids (geckos have a transparent membrane that protects their eyes)
- Specialized toe pads that allow them to climb smooth surfaces
- A short, wide tail
- Soft, velvety skin
Geckos also have a few unique behavioral traits. They are able to vocalize, making chirping sounds to claim territory or attract mates. Geckos are mostly nocturnal and excellent climbers. They can even climb upside down on ceilings thanks to their specialized toe pads.
Examining Physical Features
When trying to identify a lizard as a gecko, the best place to start is by examining its physical features and seeing if they match the gecko characteristics listed above. Here are some specific things to look for:
Eyes
– Large, bulbous eyes positioned on the sides/top of the head
– Vertical slit-shaped pupils (like a cat’s eye)
– No eyelids or blinking – the eyes will always appear open
Toes
– expanded toe pads on the underside of the feet, with fine rows of small hairs called setae
– able to strongly grip surfaces, allowing them to climb smooth vertical surfaces including glass
– toes spread flat when climbing, then fold neatly against the foot while at rest
Skin
– Soft, flexible, and velvety to the touch
– Often patterned with small tubercles (bumps), ridges, or folds
– May have loose flaps of skin around the neck, legs, and sides of the body
Tail
– Short and wide compared to body size
– May be flattened from side to side
– Often has segmented constrictions giving it a banded appearance
Size and shape
– Head is short and wide
– Body is flattened dorsoventrally (from back to belly)
– Limbs/digits are short and compact
– Ranges from 1 inch to 12 inches in length
If a lizard matches most or all of these physical criteria, it’s likely you’re looking at a gecko. However, appearance alone isn’t always enough for a definitive ID. Their behavior and habitat can also provide clues.
Observing Behavior
Geckos have distinctive behavior patterns that differentiate them from other lizard families:
- Nocturnal activity – geckos are primarily active at night and sleep during the day. You’re more likely to see them out hunting insects after dark.
- Vocalizations – geckos can make various chirping sounds and they are quite vocal compared to other lizards.
- Climbing ability – geckos are great climbers capable of scaling smooth vertical surfaces like glass using their specialized toe pads.
- Slow, stalking movements – geckos are ambush predators and move slowly/stealthily when hunting.
- Cryptic/camouflaging colors and patterns – allows them to blend into their environments.
If you observe a lizard exhibiting nocturnal activity, vocalizing, climbing smooth surfaces, and generally stalking prey while camouflaged, these are strong clues that it may be a gecko.
Habitat
Geckos occupy diverse habitats globally but do have habitat preferences:
- Tropical and subtropical forests
- Deserts and dry grasslands
- Urban areas, human dwellings
- Rocky outcrops and cliffs
They are also often associated with trees and bushes since they climb vegetation easily. Geckos like warm environments and require heat to be active. If you find a suspected gecko in these types of habitats, it supports the gecko ID.
Some key habitat clues include:
- Found on vertical surfaces like tree trunks, rocks, walls, etc. Rather than ground-dwelling.
- Associated with human homes, often found on walls or ceilings indoors in tropical areas.
- Hiding under bark, in rock piles/crevices, or in bushes and shrubs.
- Active at temperatures above 60°F – will become lethargic in cooler weather.
A lizard found displaying niche habitat preferences like vertical perching, human home association, and requiring warmth matches the expected ecology for geckos.
Range and Distribution
Geckos have a worldwide distribution but are most abundant and diverse in warm regions. Some key details about their geographic ranges:
- Most diverse and abundant in the tropics and subtropics globally.
- Common gecko regions include Central/South America, Africa, Southern Europe, South Asia, Australia.
- Less common in cooler climates but some species range into temperate regions seasonally.
- A few hardy species can even survive in deserts and arid grasslands.
Here is a table summarizing the distribution of different gecko families worldwide:
| Gecko Family | Region |
|---|---|
| Gekkonidae (True geckos) | Cosmopolitan, especially abundant in warm regions worldwide. |
| Phyllodactylidae (Leaf-toed geckos) | Americas, Africa, Mediterranean Europe. |
| Eublepharidae (Eyelid geckos) | Central Asia, North Africa, North America. |
| Sphaerodactylidae (Dwarf geckos) | Central/South America, Caribbean, Southern North America. |
If you encounter a suspected gecko in one of these warm, tropical or subtropical regions, it’s much more likely to be correctly identified compared to cooler temperate areas farther from the equator. Only a handful of gecko species extend into such areas.
Conclusion
Identifying a lizard as a gecko depends on evaluating its physical characteristics, behavior, habitat preferences, and geographic distribution for matches to known gecko traits. Look for:
- Large staring eyes, lack of eyelids, expanded toe pads.
- Nocturnal activity, vocalizations, exceptional climbing ability.
- Association with warm forests, deserts, human homes and vertical surfaces.
- Residence in tropical, subtropical, or arid environments globally.
Consider all these factors together when making an ID. Subtle differences in traits can distinguish geckos from similar-looking lizards like anoles or skinks. Proper identification usually requires examining the lizard up close. Photographs or descriptions may not provide enough detail for a definitive conclusion. Experts recommend catching the lizard with gloved hands or an insect net for the most reliable identification based on combined physical, behavioral, and geographic clues. Handle with care and release promptly with minimal stress to the animal.
Geckos are a unique and fascinating group of lizards with specialized adaptations like sticky toe pads that allow them to thrive across diverse environments worldwide. With careful sleuthing using the criteria described here, anyone can hone their skills at properly distinguishing geckos from the many other lizard species they may encounter.
