In 2010, the conservation group WildEarth Guardians petitioned the U.S. government to list 11 species of tarantula as endangered or threatened.
The species are in subcategory of tarantula called Poecilotheria, which are some of the world’s largest spiders. Their bodies are between 1.5 and 3.5 inches long, with leg spans of 6 to 10 inches.
The hairy spiders are known to move quickly and are poisonous to humans. A bite can cause pain and muscle cramps.
They vary in color and are called “arboreal” because they live in tree holes and dead trees, among other places.
Because people are afraid of them, they “are usually killed when encountered” in Sri Lanka, the agency wrote in its final rule.
The tarantulas are also popular among spider enthusiasts because of their size and unusual colors, and collecting them from the wild could negatively impact their populations, the agency concluded.
“Due to the patchy distributions and poor dispersal abilities of tarantulas, collection of several individuals from a single location could potentially reduce the abundance or distribution of a species, especially those with restricted distributions,” the agency wrote.
And the effects of global climate change have affected tarantula populations as well.
Sri Lanka, like other countries, has seen an increase in average temperatures over the past decades, as well as a decrease in rainfall. Environmental changes affect tarantulas’ ability to maintain their body temperatures.
Deforestation in Sri Lanka has also contributed to a loss of the tarantulas’ habitat, the agency found.
Some parts of the island have coconut plantations that are suitable habitat for one of the species, but those areas “are becoming increasingly fragmented due to demand for housing.”
The agency issued its proposed rule in December 2016 and published the final rule this week after reviewing 115 comments from the public.
Sri Lanka, an island about the size of West Virginia, has lost a great deal of its forest cover in recent decades. The island nation is also projecting a population increase of 800,000 in the future, the agency wrote.