Goliath bird-eating tarantulas are the largest spiders by mass in the world (the giant huntsman spider has a larger leg span), belonging to the genus Theraphosa. They can have a body length of 5.1 inches and a leg span of a foot. At the time I started keeping tarantulas in the late 1970s, there was only one species known, Theraphosa blondi (though at the time it was being sold as Theraphosa leblondi). Blondi, described in 1804, was thought to be the only species of goliath until in 1991, the goliath pink foot (Theraphosa apophysis), was described. Then, in 2010, the burgundy goliath (Theraphosa stirmi) was described. Though all three species look similar as adults, the spiderling and juvenile stages show the greatest differences between species.
TARANTULA GENUS SPOTLIGHT: Brachypelma
The first tarantula I ever had was Brachypelma hamorii, then known as smithi. I had her for fifteen years, after my parents bought her for me in 1979 from a local pet shop. Since then, though I now keep many genuses of tarantulas, Brachypelma will always hold a special place in my heart. They are easy to keep, are very long lived, and all are absolutely beautiful. In 2019, many Brachypelma species were re-designated under the new genus Tliltocatl. According to the World Spider Catalog, there are currently eight species of Brachypelma, all originating from Mexico. Thanks to captive-breeding efforts within the United States, most of these are readily available as spiderlings. All species are protected, and trade is regulated under CITES.