As the weather gets colder and winter approaches, you may start to notice fewer lizards scurrying around your backyard or local park. If you’ve ever wondered where these cold-blooded creatures disappear to when the temperatures drop, you’re not alone.
Many people are curious about the winter habits and behaviors of lizards.
If you’re short on time, here’s a quick answer to your question: Most lizards find shelter underground or in holes and crevices and become dormant or slow down their metabolism to survive the winter months. They re-emerge when it starts to warm up in spring.
In this comprehensive article, we’ll take an in-depth look at where different types of lizards go and what they do to survive the colder months. We’ll cover topics like brumation, hibernation, migration, and winter shelter and behavior for common lizard species found across North America.
Brumation and Hibernation Help Lizards Conserve Energy
Brumation is Like Hibernation for Reptiles
When the temperature drops and the days grow shorter, many cold-blooded reptiles like lizards enter a dormant state called brumation. This period of inactivity and decreased metabolism allows them to survive harsh winter conditions when food is scarce.
Brumation is essentially the cold-blooded version of mammalian hibernation. Instead of maintaining a high, constant body temperature like mammals, reptiles allow theirs to rise and fall with their surroundings.
During brumation, a lizard’s body temperature will drop significantly, and its breathing and heart rate will slow.
Hibernation Involves Long Periods of Deep Sleep
Hibernation enables mammals like bears to avoid expending energy during winter when food is limited. They retreat to dens and enter deep sleep states where their metabolism and body temperature drop dramatically.
Similarly, the metabolic changes of brumation allow reptiles to conserve energy. Lizards will remain inactive for days or even weeks, emerging occasionally to bask in the sun when conditions permit before retreating back to their burrows or crevices.
Lizards Lower Their Metabolism and Body Temperatures
- Brumation metabolic rate can be less than 10% of normal levels
- Body temperature may decline by up to 20°F/12°C but prevent freezing
- Breathing and heart rate also slow down significantly
The extent of brumation depends on the species and climate. For example, the common wall lizard’s (Podarcis muralis) body temperature can drop from 95°F to as low as 37°F before they emerge to bask and raise it again (source). This fluctuating temperature regulation persists all winter.
Further north, extremely cold-tolerant species like the common side-blotched lizard (Uta stansburiana) can survive with body temperatures dipping below freezing temporarily. Through brumation, they endure harsh winters despite being cold-blooded!
Many Lizards Seek Insulated Shelters and Burrows
Tree Bark and Rock Crevices Offer Protection
When frigid winter weather arrives, various species of lizards seek refuge under loose tree bark or in narrow gaps between rocks and crevices. These snug spaces act as insulation, helping the cold-blooded reptiles conserve body heat to survive.
For instance, Eastern fence lizards and certain skinks often hibernate in the hollows behind tree bark during winter. Alternatively, the Northern Alligator Lizard and many Horned Lizards hide themselves beneath rocks or in the cracks of boulders when temperatures drop.
Some Lizards Dig Burrows in Soil or Leaf Litter
Some resourceful lizards like Gila Monsters and Texas Horned Lizards use their front limbs to burrow tunnels in loose soil or padding of dead leaves. These subterranean nests allow the reptiles to avoid exposure to winter’s freezing winds and plummeting temperatures.
Interestingly, a 2008 study revealed that certain lizards intentionally dig burrow systems with both north-south and east-west orientations. This burrow design helps them find the optimal temperature all winter long as the sun’s angle changes.
Hollow Logs and Holes Provide Winter Refuge
Various reptiles crawl into hollow fallen logs, empty mammal burrows, gaps beneath large rocks, and other natural cavities to escape winter conditions. For example, the Eastern Box Turtle is renowned for overwintering in old fox or woodchuck tunnels.
Also, Rough Green Snakes often share gopher tortoise burrows, benefiting from relatively warmer temperatures. And Short-horned Lizards even occupy deserted mammal dens located beneath the snow line for better insulation against chill factors.
Migrating South Helps Some Cold-Intolerant Species
Certain Tropical Lizards Can’t Handle the Cold
Lizards that thrive in tropical environments often lack the physiological means to survive frigid winter temperatures. For instance, the green anole (Anolis carolinensis), a small arboreal lizard native to the southeastern United States and Caribbean islands, experiences chill coma once temperatures drop below 50°F (10°C) according to a report by University of Rhode Island.
Without the ability to brumate (enter a winter dormant state) like some of their cold-hardy cousins, migration is these lizards’ only option for avoiding freezing to death.
Long-Distance Migration Takes Lizards to Warmer Climates
Not all lizards migrate equal distances when cold weather sets in. The most epic journeys are made by marine iguanas (Amblyrhynchus cristatus), herbivorous lizards native to the Galápagos Islands. Research from Princeton University reveals that certain populations embark on an astonishing 2,000-mile migration by rafting on vegetative mats across the ocean to nesting sites on the South American mainland.
By traveling to the tropics, marine iguanas escape the cool 60°F seasonal lows on the Galápagos.
Meanwhile, others reptiles like the Texas horned lizard (Phrynosoma cornutum) need only travel short distances regionally to find warmer microclimates. A collaborative 2020 study by zoos and universities found this iconic lizard makes altitudinal movements within Texas to avoid freezing.
Through scientists strapping tiny radio transmitters to them, the lizards demonstrated vertical shifts to lower elevations as little as 30 miles away once cold fronts set in. Their migration may be modest, but it gets them out of harm’s way.
Some Lizards Only Migrate Short Distances
Not all migratory reptiles living in temperate regions travel vast distances when the mercury plummets. The common wall lizard (Podarcis muralis), for example, is a modest migrant that merely moves from open habitats to covered hibernation sites nearby to wait out winter in southern Europe, as identified in a Slovenian ecology study.
Come springtime, the wall lizards venture back out to revive their normal activities.
Even slight environmental variations enable some cold-sensitive species to find refuge without going far. Smith’s dwarf chameleons (Bradypodion taeniabronchum), tiny lizards from South Africa, seek warmer microclimates by moving just a few feet.
A 2018 paper by University of California researchers found these chameleons select narrow crevices in rock cracks that provide insulation yet still receive enough sunlight to allow them to periodically bask.
Winter Behavior Varies by Species and Climate
Desert Lizards Remain Active in Warm Areas
Lizards living in warm desert climates often remain active year-round. For example, the zebra-tailed lizard (Callisaurus draconoides) continues hunting insects and basking in the sun during mild desert winters (see Desert Museum).
Many desert dwellers rely on their ability to tolerate extreme heat to survive cold nights.
Other desert lizards may become less active in winter but do not truly hibernate. The chuckwalla (Sauromalus ater) spends more time hiding in rock crevices from November through February but emerges to bask periodically (Animal Diversity Web).
Nocturnal Gecko Species Find Daytime Shelter
Nocturnal geckos adapt to colder temperatures by hiding during daylight hours. Species like the common house gecko (Hemidactylus frenatus) take cover in dark, insulated spaces and become dormant. Their heart rates and metabolism slow dramatically during this sheltering period (National Wildlife Federation).
Other geckos may literally hang out underground! The bizarre-nosed Cape thick-toed gecko (Pachydactylus capensis) of southern Africa digs burrows or occupies rodent burrows during winter dormancy (Animal Diversity Web).
Small Lizards Are Vulnerable to Predators and Exposure
Very small or cold-intolerant lizard species spend winter hiding in burrows, crevices, or underground chambers. Hibernating helps them conserve energy and shelter from freezing temperatures. For example, northern alligator lizards (Elgaria coerulea) in mountain climates burrow as much as three feet underground, according to Animal Diversity Web.
Without proper shelter, small lizards would quickly die from exposure or fall victim to hungry birds. Researchers hypothesize that high winter mortality particularly impacts hatchlings and juvenile lizards.
Conclusion
To sum up, lizards employ a variety of strategies to survive the harsh conditions of winter, depending on the species and local climate. Brumation and hibernation allow lizards to conserve energy in colder areas. Migrating south is an option for lizards that can’t tolerate dropping temperatures.
And seeking insulated shelter and remaining inactive helps many lizards ride out the winter months.
Understanding where local lizards go and what they do in winter allows us to support these fascinating creatures as seasons change. With mindful landscaping choices and habitat protection, our backyards and parks can continue to provide refuge for overwintering lizards year after year.
