There are very odd organisms living 2500 meters deep in lithosphere, under the ocean, that have such a low rate of metabolism that they divide once every hundreds, perhaps a thousand years.
They have only been discovered recently. Their habitat is isolated from the surface biosphere. It doesn’t depend on photosynthesis. In lithosphere, under the ocean, the food chain starts with radioactive decay. These organisms divide so slowly that it’s difficult to even measure their metabolic rate to tell how often they divide. They are not animals though. They are unicellular organisms. Their existence gives hope to our search for extraterrestrial life forms on other planets. If life on Earth can survive and thrive isolated from the surface, then it’s conceivable that it can on other planets, in their deep lithosphere as well. Perhaps life as we know it started in such habitat too.
To answer your question: Because of slow rate of metabolism, lithosphere life forms can divide (are born) so rarely, that it might be a thousand years between each division. They are not animals though. They are much simpler single-celled organisms. There is no known multi cellular life form, animal, that I’m aware of, that is born once every thousand years.
Credit : Quora
Picture Credit : Google