urban areas they preferentially inhabit, particularly those with high degrees of habitat fragmentation. To compound this, they also are capable of operating on higher densities, which leads to an increase in gecko sightings and biomass in an area, even after reducing native species' density. The common house gecko also displays a higher tolerance to high light levels, which may allow for an increased risk-reward pay off in hunting endeavours. There is also some limited evidence for cannibalism, hunting on other small gecko species, particularly juveniles. Most of this evidence is in laboratory conditions, with several studies failing to find evidence of cannibalism in the wild for this species. Some males are more territorial than others. Territorial males will display larger heads, with a more pronounced head shape. This increase in head size incurs the cost of a poorer performance in escape sprint time. This suggests selective pressure prioritises the biting force capacity of the male, over their capacity to escape quickly. On the contrary, increases in female head size are met with a proportionate increase in hind limb length and no decrease in speed. Though both sexes use escape sprinting as a survival strategy, males are more likely to need to stop and fight using biting, due to the reduced mobility caused by disproportionate head to hind leg size, which in turn is correlated with localised territorial behaviours. The success of the common house gecko can also be explained through other elements of competition, such as postural displays and movement patterns. An example of this is how the common house gecko can trigger an "avoidance response" in the mourning gecko, causing it to avoid a specific area where food may become available. Though triggering avoidance in other species, they themselves can tolerate the presence of other gecko species well, regardless of whether those species are smaller or larger, faster or slower, or more physically aggressive or not. This allows them greater access to feeding areas and territories, making them a highly successful invasive species. Physiology The common house gecko is ectothermic ("cold-blooded") and displays a variety of means of thermoregulating through behaviour. Its physiology has ramifications for its distribution and nature of interaction with native species, as well as reproductive success as an introduced species. Metabolically, the demand of the common house gecko is not significantly variable from other lizard species of a similar size, with oxygen consumption appearing congruent