Skinks (Scincidae) are a diverse family of lizards found across nearly every continent. They are characterized by smooth, glossy scales and often small limbs. Understanding their activity patterns requires examining their biological needs and the environmental pressures that shape their daily routines.
Typical Activity Patterns of Skinks
The vast majority of skink species are overwhelmingly diurnal, meaning their primary active phase occurs during daylight hours. This pattern is directly linked to their nature as ectotherms, as they cannot generate sufficient internal heat and must rely on external sources to regulate their body temperature. To be agile enough for essential functions like foraging and escaping predators, a skink’s internal temperature must reach a specific, elevated level.
Skinks begin their day by engaging in heliothermy, or sun-basking, positioning themselves in direct sunlight to absorb warmth. Many species maintain a consistent preferred body temperature, often around 32 to 34 degrees Celsius, necessary for optimal physiological function. Once warmed, their main activity is foraging for small invertebrates such as insects and arthropods.
Activity peaks often occur in the early morning after warming and again in the late afternoon as temperatures begin to moderate. During the intense heat of midday, many skinks temporarily retreat to shaded areas or underground to avoid overheating. This reliance on solar energy for mobility dictates a schedule entirely tied to the presence of daylight.
What Do Skinks Do After Sunset?
As the sun sets and ambient temperatures drop, the diurnal skink enters a resting phase crucial for energy conservation and safety. Skinks seek secure microhabitats to retain residual heat absorbed during the day. Typical resting spots include beneath rocks, inside hollow logs, under dense leaf litter, or within burrows.
This period of inactivity is necessary because the skink’s metabolism slows significantly without external heat, making prolonged movement inefficient. The shelter buffers the reptile from the rapid decline in nighttime temperatures, helping maintain a stable body temperature until morning. Retreating also minimizes exposure to nocturnal predators, such as owls, foxes, and snakes.
The safety provided by these retreats is important, as a cold skink is slow and unable to use speed as a defense mechanism. By remaining concealed, the animal conserves energy needed for the next day of foraging and thermoregulation.
Factors That Influence Nighttime Movement
While diurnal behavior is the norm, some species display crepuscular or even nocturnal tendencies, though this is the exception. Researchers classify a minority of species as cathemeral, meaning they have a mixed activity pattern that includes movement outside of daylight hours. This opportunistic nighttime activity is usually triggered by specific environmental conditions.
One primary factor influencing rare nocturnal movement is extreme daytime heat, particularly in arid or desert environments. If daytime temperatures become too high to safely forage, some skinks may emerge after sunset once the ground temperature has dropped. This allows the animal to complete necessary activities without risking lethal overheating.
A small percentage of skink species, particularly those with fossorial (burrowing) lifestyles, are genuinely nocturnal or favor cooler temperatures. For instance, the Australian fossorial skink, Saiphos equalis, is more active at night and selects a relatively cool body temperature range. Some species, like the desert skink Ctenotus pantherinus, are predominantly diurnal but show opportunistic nocturnal activity, sometimes specifically to hunt prey like termites.