Golden lancehead facts for kids
Quick facts for kids Golden lancehead |
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| Conservation status | |
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| Genus: |
Bothrops
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| Species: |
insularis
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The Bothrops insularis, also known as the golden lancehead, is a very venomous snake. It's a type of pit viper and is found only on one special island. This island is called Ilha da Queimada Grande, located off the coast of São Paulo state in Brazil.
The snake gets its name "golden lancehead" from its light yellowish-brown color and the unique shape of its head. Its head is long and pointed, like a lance. This snake is considered one of the most venomous snakes in all of Latin America.
Contents
What Does the Golden Lancehead Look Like?
Size and Appearance
Golden lanceheads are usually about 70 to 90 centimeters (27 to 35 inches) long. Some can even grow up to 118 centimeters (about 46 inches).
Their skin is a pale yellowish-brown color. They have darker blotches on their backs that can be triangular or square. These blotches can be arranged in different ways, sometimes forming a banded pattern. Their belly is a plain pale yellow or cream color. When these snakes are kept in zoos, their yellowish color might get darker. This could be because they don't get enough sunlight to control their body temperature.
The name "lancehead" comes from the distinct head shape of all snakes in the Bothrops group. Their heads are somewhat long and come to a point at the nose. The golden lancehead also has a longer tail than its closest relative, the B. jararaca. This longer tail probably helps it move through trees and catch bigger prey like birds, even when it's young.
Venom
The golden lancehead lives on an island with no large mammals. Because of this, its venom has changed over time to be very strong against its main prey: birds, insects, and other cold-blooded animals. As the snake gets older, its venom becomes even more powerful.
Scientists have studied the venom of the golden lancehead. They found it is about five times stronger than the venom of the B. jararaca. It's also the fastest-acting venom among all Bothrops snakes.
Since the golden lancehead lives on an island where no humans live, there are no official records of people being bitten by them. However, other lancehead snakes are responsible for many snakebites in North and South America. If a person is bitten by a lancehead snake, they can experience serious health problems. These might include swelling, pain, nausea, and bleeding. It's very important to get medical help right away if someone is bitten.
Reproduction and Life Cycle
Golden lanceheads usually mate in August and September. They can mate both in trees and on the ground. Like most vipers, the golden lancehead gives birth to live young, instead of laying eggs.
On average, a female golden lancehead will have about 6 or 7 babies at a time. We don't have exact information on how big golden lancehead babies are when they are born. However, they are probably similar in size to Bothrops jararaca babies. Those babies are about 24.5 to 25.3 centimeters (about 9¾ inches) long and weigh around 9 to 10 grams (about ⅓ ounce).
The female snakes' breeding cycle might be linked to when migratory birds visit the island. This is because these birds are a very important food source for the snakes.
Where Do Golden Lanceheads Live?
This snake species lives only on Queimada Grande Island in Brazil. This island is often called Snake Island. The island is quite small, only about 43 hectares (or 430,000 square meters).
The Brazilian government strictly controls visits to the island. This is to protect the snakes and their unique home.
What is Their Habitat Like?
Queimada Grande Island has a "subtropical" or "tropical moist forest" climate. The weather is very mild; the temperature rarely drops below 18 degrees Celsius (64°F) and usually stays below 22 degrees Celsius (72°F).
The island has different types of areas, including forests, open clearings, and shrubs. It's a very rocky place and hard to reach. No humans live on the island, and there are no other mammals either.
The quality of the snake's home on the island is slowly getting worse. This is partly because the Brazilian Navy removes some plants to maintain a lighthouse there.
Where Do They Like to Hide?
Golden lanceheads can often be found in trees, especially when they are hunting for food. They also like to hide under leaf litter (fallen leaves) or in cracks in rocks. They do this especially when the weather is bad or after they have eaten a meal.
Family Tree and How They Evolved
A study in 2005 showed that the golden lancehead is closely related to the Bothrops jararaca. This snake lives in southern Brazil, Paraguay, and northern Argentina.
Scientists believe that golden lanceheads came from a group of B. jararaca snakes. These snakes became separated on Queimada Grande Island a long time ago. At that time, the island was connected to the mainland. But then, sea levels rose, and the island became isolated.
There are 37 species in the Bothrops group, and all of them live in South America. Another common name for snakes in this group is "fer-de-lance." The fact that there are no native mammals on Queimada Grande Island has greatly influenced how the golden lancehead has evolved.
Golden Lancehead's Place in Nature
Who Eats Golden Lanceheads?
There isn't much information about what animals might eat adult golden lanceheads. However, there are birds, spiders, millipedes, and lizards on the island. These animals could potentially prey on young snakes. Since the island is hard to access, scientists haven't been able to observe these snakes very much. So, there might be more predator-prey relationships than we know about.
What Do Golden Lanceheads Eat?
Adult golden lanceheads mainly eat birds that perch in trees. They have also been seen eating lizards. Sometimes, they even eat other golden lanceheads (cannibalism). Baby and young golden lanceheads mostly eat insects and other small creatures without backbones. Adult snakes can survive by eating just one or two birds a year, even though over 40 different bird species visit the island.
Who Do They Compete With?
Adult golden lanceheads are the only animals on Queimada Grande Island that are known to eat birds. There are other animals on the island, like frogs, lizards, and birds, that eat insects. However, insects are usually very common in nature, so there might not be much competition for them. More studies would be needed to see if young golden lanceheads have to compete with other animals for food.
Protecting the Golden Lancehead
Conservation Status
The golden lancehead is listed as critically endangered (CR) on the IUCN Red List. This means it faces a very high risk of becoming extinct in the wild.
Here's why:
- The area where it lives is very small (less than 100 square kilometers).
- This area is either broken up into tiny pieces or is just one single location.
- The quality of its habitat is continuing to get worse.
- The actual space it occupies is tiny (less than 10 square kilometers).
Even though the population is stable right now, its limited habitat makes it very vulnerable. In 2021, scientists estimated there were between 2,414 and 2,899 golden lanceheads on the island.
Limited Home Range
Because the island where these snakes live is so small, it can only support a small number of snakes. This means that if anything bad happens, like a disease or a fire, the species could be in serious trouble. If the population on Queimada Grande Island is wiped out, the golden lancehead will be gone from the wild forever.
Habitat Loss and Over-Collecting
In the past, people purposely started fires on Queimada Grande Island. They wanted to kill the snakes so they could use the island to grow bananas. The Brazilian Navy has also caused some habitat destruction by removing plants to keep the lighthouse working.
Scientists have also collected too many snakes in the past. Because of these problems, experts say that we cannot assume this snake is safe. A study estimated that if 25 to 40 snakes were collected each year, it could lead to the species dying out genetically over 100 years. Now, you need a special permit to collect these snakes for scientific research.
Unfortunately, the illegal wildlife trade is also a big threat. Because the golden lancehead is so rare, people have offered a lot of money (up to $30,000 in 2008) for these snakes on the black market.
Less Food Available
In 2019, a snake expert named Bryan Fry reported that the migratory birds that golden lanceheads rely on for food are visiting the island less often. This is happening because of deforestation (cutting down trees) on the Brazilian mainland. This means less food for the snakes.
How Golden Lanceheads Behave
These snakes can be found both on the ground and in trees. While they don't have a tail that can truly grip branches, they often use plants to hunt. They are usually found in trees when they are looking for birds to eat. But they tend to hide under leaf litter or in rock crevices during storms or after they have eaten.
Unlike many other venomous snakes that strike their prey, let go, and then follow it, the golden lancehead holds onto its prey after biting it. This is probably an adaptation for hunting birds. It's much harder to track a bird that flies away after being bitten, so holding on ensures the snake gets its meal.
Other lancehead snakes have been seen wiggling their tails to attract prey. This behavior hasn't been observed in the golden lancehead yet. However, since there are animals on the island that might be attracted by tail wiggling, and golden lanceheads are good at finding opportunities, it wouldn't be surprising if this behavior is eventually seen.
