Giant garter snake facts for kids
Quick facts for kids Giant garter snake |
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| Conservation status | |
| Scientific classification | |
| Genus: |
Thamnophis
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| Species: |
gigas
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The giant garter snake (Thamnophis gigas) is the biggest type of garter snake. It's quite rare and lives mostly in water, found only in the wet areas of central California.
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About the Giant Garter Snake
The giant garter snake is the largest garter snake species. Adult snakes can grow from about 3 to 5.4 feet (94 to 165 cm) long. Female snakes are usually longer and bigger than males.
These snakes have special scales that feel a bit rough, called keeled scales. They have a bright yellow stripe down their back. This stripe stands out against their dark grey or black body. They also have two more yellow stripes on their sides. Sometimes, they might have a checkered pattern instead of stripes.
Giant garter snakes are venomous, but their venom is very mild. It's not harmful to humans. At most, a bite might cause a small, itchy red rash. They use their mild venom to help catch their prey.
Where They Live
You can find the giant garter snake in Central California. Long ago, they lived across a much larger area in California's Sacramento and San Joaquin valleys. But now, their homes are much smaller and spread out in the Sacramento Valley.
These snakes love water and are called "semi-aquatic." This means they spend a lot of time in water. They are almost always found just a few feet from water during their active season. Because they need water so much, it's hard for them to move to new places. This also means their groups of snakes get separated, as areas without water are too difficult for them to cross.
Historically, these snakes lived in natural wet areas like marshes. But many of these places have been destroyed. Now, most giant garter snakes live in man-made wet areas. These are often rice fields and their canals.
Giant garter snakes prefer calm or slow-moving water with plants growing out of it. They use the water to control their body temperature. Water that is too deep or moves too fast is too cold for them. The plants help hide them from predators. Even though they depend on water, they spend most of their time on land during their active season. They spend all winter on land, sleeping underground in a state called brumation.
When they are not underground, they look for piles of leaves or plants to hide in. This protects them from predators and bad weather. They avoid open or rocky areas. Snakes living near rice farms use the canals in spring and fall. They use the rice fields themselves during the active season. These fields offer good homes with plenty of food, water, and cover. Since most giant garter snakes now live in rice farming areas, many are on private land. This can make it harder for scientists to study and protect them.
Behavior and Life
Giant garter snakes are active during the day. They are awake from spring until late fall. In winter, they sleep underground on land. They are very aquatic and are active when the water is about 68°F (20°C) or warmer. When the water gets colder, they go underground to sleep.
They have several natural enemies. Young snakes are often eaten by American bullfrogs and California kingsnakes. Larger birds like raptors also hunt them. Giant garter snakes have learned to dive into the water quickly to escape these birds. If a giant garter snake feels threatened, it can release a stinky musk from its body. This helps scare away predators, just like other garter snakes do.
What They Eat
Because they live mostly in water, giant garter snakes eat fish, frogs, and tadpoles. In the past, they ate local animals like the Sierran treefrog. But now, they mostly eat animals that are not native to the area. The most common of these is the American bullfrog. Adult giant garter snakes often eat young bullfrogs and tadpoles.
Scientists have also found that giant garter snakes can have higher levels of heavy metals, like mercury, in their blood. This happens when they eat fish that have a lot of mercury. More research is needed to see if this harms the snakes.
Reproduction and Life Cycle
Male giant garter snakes come out of their winter sleep between March and mid-May. They then search for a female to mate with. Their winter dens are usually more spread out than other garter snakes. This means males have to use more energy to find a mate.
There are differences in how male and female snakes prepare for reproduction. Males tend to be less healthy in early spring. This is because they use their energy to find mates and reproduce, rather than growing or eating. Females, however, become healthier around the same time. This extra energy helps their babies grow inside them. Pregnant female snakes are also seen basking in the sun more often. Scientists think the warmth helps their embryos develop.
Giant garter snakes are ovoviviparous. This means they carry their eggs inside their bodies, but they give birth to live young. After mating in the spring, babies are born from mid-July to early October. On average, a female snake has about 17 babies in a litter. Larger female snakes usually have more babies than smaller ones. The size of the young snakes also depends on how much food and other resources are available that year.
Conservation Efforts
Many wetland homes for the giant garter snake have been destroyed. Because of this, the species is listed as endangered by both state and federal governments. The groups of giant garter snakes in the San Joaquin Valley are now very small and separated. They have disappeared from 98% of their old homes in the San Joaquin Valley.
The giant garter snake has done better in the Sacramento Valley. This is because rice farming and its canals have created new homes for them. However, when rice fields are left empty for a season, the snake populations seem to move away from the nearby ditches.
Besides losing their homes, new predators are also a problem. Animals like the American bullfrog and the northern water snake are not native to the area. They may be stopping the giant garter snake populations from recovering. People are trying to create new man-made wetlands to give the giant garter snake good places to live. But it's still too early to tell if these efforts will truly help this threatened species recover.
