Number 16 (spider)

Number 16 (c. 1973 – 2016), also known as #16,[1] was a wild female trapdoor spider (Gaius villosus, family Idiopidae) that lived in North Bungulla Reserve near Tammin, Western Australia. She died in 2016, at an estimated age of 43 years, and is the longest-lived spider recorded to date.[1] Number 16 did not die of old age, but was most likely killed by a parasitic wasp sting.[2]

Number 16
SpeciesGaius villosus
North Bungulla Reserve, Western Australia
Died2016 (aged about 43)
North Bungulla Reserve, Western Australia
Known forSubject of long-term monitoring project; oldest known spider[1]

Long-term monitoringEdit

Number 16 was studied in the wild by arachnologist Barbara York Main from March 1974 until 2016.[1][A] She was part of the first cohort of dispersing spiderlings to establish a burrow at the study site, and her burrow was the 16th to be marked with a peg.[1] By 1978, Main had tagged 101 burrows at the study site, within a few metres of each other.[4]

Number 16 spent her entire life in the same burrow, which is typical for her species.[2] For over 40 years, her status was monitored by Main and her collaborators either six-monthly or annually.[1] As Number 16 became older, the researchers developed a tradition of always checking her burrow first when they visited the site.[4]


On 31 October 2016, researcher Leanda Mason discovered Number 16's burrow in disrepair, and the spider missing.[4] The silk plug of her burrow had been pierced by a parasitic spider wasp, suggesting that she had been parasitised, either before or after death.[1] During a survey six months earlier, Number 16 had been alive.[1] “She was cut down in her prime [...] It took a while to sink in, to be honest," said Mason.[4] The spider's death received widespread publicity in late April 2018, with the publication of a research article in the journal Pacific Conservation Biology.[1] Based on the burrow fidelity of females of her species, the researchers concluded with a "high level of certainty" that Number 16 was 43 years old at the time of her death.[1]



  1. ^ Number 16 would have hatched in late 1972 or early 1973. In Aganippine trapdoor spiders: "Eggs are laid during late spring and early summer (October through November). The young emerge from the egg cocoon during midsummer (late December through mid-January). The brood animals remain in the female's burrow until early winter, emerging only after substantial rains when the ground is wet and soft."[3]


  1. ^ a b c d e f g h i j Mason, Leanda Denise; Wardell-Johnson, Grant; Main, Barbara York (2018). "The longest-lived spider: mygalomorphs dig deep, and persevere". Pacific Conservation Biology. 24 (2): 203. doi:10.1071/PC18015.
  2. ^ a b "World's oldest known spider dies at 43 after a quiet life underground". Agence France-Presse. 30 April 2018.
  3. ^ Main, Barbara York (1957). "Biology of Aganippine trapdoor spiders (Mygalomorphae: Ctenizidae)". Australian Journal of Zoology. 5 (4): 402–473. doi:10.1071/ZO9570402.
  4. ^ a b c d Selk, Avi (1 May 2018). "The extraordinary life and death of the world's oldest known spider". The Washington Post. Retrieved 2 May 2018.