1. Regenerating flatworms
These ᴄʀᴇᴇᴘʏ crawlers, also known as planarian worms, are famous for their regeneration abilities, where a worm ᴄᴜᴛ across or lengthwise can form two separate worms. This apparently limitless regeneration also applies to aging and ᴅᴀᴍᴀɢᴇd tissue, allowing the worms to cheat ᴅᴇᴀᴛʜ indefinitely, according to a study at the University of Nottingham.
2. The most indestructible species on the planet
Anything that tries to ᴋɪʟʟ a ᴛᴀʀᴅɪɢʀᴀᴅᴇ will quickly realize they encountered practically immortal animals. These creatures are capable of sticking around for thousands of years or even indefinitely “by entering a state of ᴄʀʏᴘᴛᴏʙɪᴏsɪs, whereby their metabolism comes to a halt,” says Ira S. Pastor, CEO of Bioquark Inc.
3. Ʀᴀᴅɪᴀᴛɪᴏɴ-ʀᴇsɪsᴛᴀɴᴛ ʙᴀᴄᴛᴇʀɪᴜᴍ
Dᴇɪɴᴏᴄᴏᴄᴄᴜs ʀᴀᴅɪᴏᴅᴜʀᴀɴs, a ᴘᴏʟʏ-ᴇxᴛʀᴇᴍᴏᴘʜɪʟɪᴄ ʙᴀᴄᴛᴇʀɪᴜᴍ, isn’t only ʀᴀᴅɪᴀᴛɪᴏɴ-ʀᴇsɪsᴛᴀɴᴛ. These immortal animals can also ᴅɪᴇ and come back to life thanks to their incredible DNA repair response. “[They] can survive cold, dehydration, vacuum, and a.c.id, and [have] been listed as the world’s ᴛᴏᴜɢʜest ʙᴀᴄᴛᴇʀɪᴜᴍ.” The Guinness Book of Records even says they “can resist 1.5 million rads of ɢᴀᴍᴍᴀ ʀᴀᴅɪᴀᴛɪᴏɴ, about 3,000 times the amount that would ᴋɪʟʟ a human!”, says Pastor.
4. T.o.ugh whales
Though not technically immortal animals, the bowhead whale is the oldest living mammal. According to Popular Science, several species of whales have been known to live for more than 70 years, though in the 1990s scientists discovered scars on the massive animals that had been made by ᴡᴇᴀᴘᴏɴs from the 1800s. The oldest known bowhead lived to be 211 years old.
5. Backward-aging jellyfish
Turritopsis doohmii,a.ka the immortal jellyfish. It has found a way to cheat ᴅᴇᴀᴛʜ by actually reversing its aging process, according to National Geographic. If the jellyfish is ɪɴᴊᴜʀᴇd or sɪᴄᴋ, it returns to its ᴘᴏʟʏᴘ stage over a three-day period, transforming its cells into a younger state that will eventually grow into adulthood all over again.