Here is the number of molluscs on the planet:
|Snails||Mollusc||1,9 x 10^17||2017||Weborus estimation|
|Slugs||Mollusc||2,6 x 10^14||2017||Weborus estimation|
|Squids||Mollusc||7,3 x 10^13||2017||Weborus estimation|
|Octopuses||Mollusc||1,1 x 10^12||2017||Weborus estimation|
|Cuttlefishes||Mollusc||1 x 10^12||2017||Weborus estimation|
Snails would have more than ten million species. Only 200,000 are listed and 80,000 described by scientists. They live between 5 and 7 years in the wild and between 10 and 15 years in captivity! The record is 30 years. A snail hibernates between 3 and 6 months per year. They are hermaphrodites, they have a penis and a vagina, produce sperm and eggs. Each litter contains 100 eggs.
The squid are on average 60 cm long. Some species can do within 20 feet. The record is held by the colossal squid, of which very little is known as it is difficult to study, with up to 46 feet. The average life expectancy of squid is short with no more than a year and a half for most species. The giant squid lives for 5 years and only reproduces once during its lifetime.
The octopus have a life expectancy of six months for small species and five years for giant octopus. The latter can be 10 feet in length and weigh up to 397 lbs.
There is at least 190 quadrillion (million of billion) of molluscs on Earth.