Reptile migrations range from a few kilometers to thousands of kilometers. They are most often associated with travel to and from egg laying sites or communal hibernacula. Marine turtles also undertake long distance migrations, as do a number of snake species.도마뱀분양
For example, Western rattlesnakes conduct extensive migratory movements between overwintering dens and summer habitat characterized by grasslands and higher-elevation forests. This behavior is thought to be driven by temperature cues.
As days lengthen and snow melts, drowsy animals like hazel dormice and fat dormice emerge from winter hibernation. They’re resuming their daily activities but they’ll be doing so on a very low energy budget, having spent months or years underground with little or no access to food. Hence, they’re at risk of running out of energy too soon and having to return to hibernation prematurely.
Reptiles that overwinter in cool localities must retreat deep into burrows, limiting their exposure to surface temperature cues and thus their capacity to anticipate seasonal changes in ambient temperatures and weather patterns (Sperry et al. 2010). However, short-term increases in overwinter temperature may stimulate emergence from extended hibernations by lowering metabolic rates and reducing the risk of freezing (Ruby 1977; Loose et al. 2011).
In contrast, ectothermic reptiles such as frogs and turtles that enter a lighter form of dormancy called brumation have the added benefit of being able to move on warm winter days, searching for water. The brumative state also allows these reptiles to replenish their energetic reserves before returning to their cold-blooded sleep.
A growing number of studies have found that rising overwinter temperature impairs reptile fitness through increasing the cost of energy-demanding thermoregulatory activity during dormancy (Chamaille-Jammes et al. 2006; Clarke and Zani 2012). More research is needed to determine whether regional or taxonomic variations in sensitivity of physiology to winter warming are attributable to genetics or environmental conditions.
Some people think reptiles don’t move during the winter, but that is not the case. Reptiles experience a process similar to hibernation that is sometimes referred to as “도마뱀분양 brumation”. During brumation, a reptile’s metabolism and heart rate slow down but they are still conscious and active. Eastern garter snakes have been seen basking in the snow and turtles can often be found swimming around on the ice. They also have unique adaptations to get oxygen during the cold months; they simply absorb it through their cloaca (aka their butts)!
Many species of reptiles migrate in response to seasonal changes or for food. Most of these migrations involve short distances, but some are much longer. Some lizards and amphibians migrate long distances to common breeding areas for reproductive purposes. Unlike these, most reptiles do not rely on water for reproduction and therefore do not undertake breeding migrations (Cogger and Zweifel 1998; Pough et al. 1998).
Climate change has a direct effect on reptiles because they are ectotherms and rely on ambient environmental temperatures to maintain critical physiological functions. Warmer environmental temperatures result in a reduced metabolic capacity and increased vulnerability to disease. This can cause reptiles to seek out new habitats in order to find the resources they require, but in our human-altered world this can be problematic because of road and urban-rural development that prevent reptiles from dispersing between suitable habitats and geographic barriers that restrict their movement.
Many reptile species have evolved complex nesting instincts. For birds this may involve meticulously constructing a nest high up in the trees, while for snakes it might mean excavating an underground burrow to hide eggs and young once they hatch. Even humans can sometimes feel a compulsion to spruce up the house before baby arrives – it’s called nesting!
Nesting can also motivate reptiles to undertake long-distance migrations. Sea turtles are a prime example: they regularly migrate to nesting beaches that are often distant from foraging grounds. This enables the same females to exploit rich food resources on several different coastal sites, increasing reproductive success (Fig. 4A).
Other reptiles exhibit a more nomadic lifestyle, such as leatherback sea turtles (Dermochelys coriacea) that undertake transoceanic migrations to reach the sites where they nest and forage. This species is able to move over large distances using fast, directed movements that take advantage of the Earth’s magnetic fields and other cues (Fig. 4B).
Other land-dependent reptiles also show directional movements in response to seasonal changes in habitat conditions. For instance, many northern temperate zone snakes, including garter snakes and rattlesnakes, migrate from their summer foraging ranges to specialized oviposition or breeding areas (Fig. 5). Water-dependent reptiles such as Arafura filensnakes also migrate between restricted ponds and floodplains at the onset of the wet season. Managers can help facilitate reptile movement by providing corridors that link needed habitat types. For example, open habitat management to forestall invasive plants and mitigate human disturbance can preserve upland dispersal corridors; and riparian buffers that retain near-water refugia for aquatic reptiles.
Reptile migration is not just about escaping cold or heat. The changing frequency, intensity, and regularity of weather events can also have profound effects on ectotherms. For example, the onset of spring or fall precipitation can make a difference to snakes relying on seasonal temperatures for food and water. These changes in the timing and frequency of rainfall can dramatically alter a species’s temperature niche, and can potentially limit its ability to accomplish essential life functions such as obtaining food, reproducing, or even surviving.
The majority of reptile migrations involve horizontal travel, with distances ranging from a few miles to thousands of miles. But some reptiles migrate vertically as well, moving from the upper zones where they breed to lower areas where they feed and rest. This type of movement is often called altitudinal migration.
Although the most famous reptile migrants are turtles, there are many others that demonstrate migratory behavior. For instance, cockchafers (Melolontha melolontha) leave the sites where they hatch as adults in order to reach feeding areas that are a short distance away. This is a form of vertical migration.
Other reptiles that display migratory behavior include garter and king snakes, which are known to move to dens for winter hibernation. And some lizards, including Desert Tortoises and the Southwestern Speckled Rattlesnake, show fidelity to their den sites, returning year after year. In addition to these migratory behaviors, some reptiles have long-distance breeding migrations.