Fertility & reproduction
Naked mole rats have remarkably long lives (up to age 37) compared to other rodents. They can also cope with very low oxygen, are resistant to pain and do not get cancer; traits that are being studied to develop new human medicines and therapies. In addition, they have the ability to breed through life, which could provide clues to help prolong human fertility. Somewhat perversely perhaps, they live in large colonies with a queen who suppresses the ability of other females to reproduce until her reign is over. When this moment comes, the other females fight each other and the winner is the new queen.
Many invertebrates, including aphids and some bees and scorpions, reproduce asexually, but the phenomenon of parthenogenesis (virgin births) also occurs in vertebrates, such as Komodo dragons and hammerhead sharks. With female-only species, every adult member can produce offspring, while in some birds, reptiles and fish, females have both male and female sex chromosomes and so can theoretically produce both sons and daughters by parthenogenesis.
Among some egg-laying fish, frogs and reptiles, the young may be anatomically male and genetically female, or vice versa, depending on whether the eggs are exposed to warm or cool environments. The spotted snow skink (Tasmanian lizard) also gives birth to live young and can switch from female to male before birth in response to external temperature, making it the only known non-egg-laying animal to do so.
Longevity
Human beings are long lived compared to other primates, with chimpanzees and orangutans living up to 50 and 55 years in the wild. The prize for oldest vertebrate goes to the Greenland shark, which reaches sexual maturity at about 150 and may live to 400 years old, although this age limit is not yet fully agreed. The oldest mammal, also swimming in the Arctic, is the bowhead whale, which scientists think may live to over 200. Other whales also do well in the longevity stakes, while a Seychelles giant tortoise believed to have hatched in 1832 has recently celebrated his 190th birthday. The rougheye rockfish may reach 205 years, and one female tracked albatross, believed to be over 70, is the world’s oldest known wild bird.
Beyond conventional mortality, scientists have been unlocking the secrets of a jellyfish called Turritopsis dohrnii, which is smaller than a human fingernail. It is able to rejuvenate itself continually, re-absorbing its tentacles and shrinking its body to return to its polyp stage on the seafloor and then spout more jellies that grow and mature again. Researchers have discovered a number of genetic variations that contribute to the jellyfish’s longevity. These genes are associated with known features of healthy ageing and this knowledge might help to find new treatments for age-related diseases such as Parkinson’s and Alzheimer’s.
Regeneration
Regeneration of body parts is another area of huge interest to biologists and health scientists. First in line is the axolotl, an aquatic salamander capable of regrowing its limbs, as well as its spinal cord, heart and other organs. When a limb is damaged or lost, stem cells gather at the end of the remaining limb, extending it and allowing for the creation of muscle skin and cartilage. As the stem cells extend, the new cartilage turns into bone, completing the regrowth process.
Other animals possessing regenerative abilities include some types of starfish that grow new bodies from severed limbs, having no blood or brain and all the vital organs they need located in each of their arms. Green iguanas will remove their tail when they feel threatened and both the river-dwelling Mexican tetra fish and the zebrafish can regenerate damaged heart tissue. Zebrafish have proved useful in modelling certain human conditions and diseases, including some types of cancer, and have been sent out into space for research purposes. The flatworm has very powerful, pluripotent stem cells that allow it to regrow an entire body from a single part, creating a clone of the original worm.
Also on the list for regenerative superpowers are chameleons (growing back tails, limbs and other parts, as well as changing colour), sea slugs (regenerating entire bodies from their heads) and octopuses (regrowing tentacles to create a better version than the original, unlike the inferior versions grown by reptiles).
Intelligence
The octopus, along with its fellow cephalopods the cuttlefish and squid, is known for its complex form of intelligence. An octopus has a widely distributed nervous system, with a significant proportion of its 500 million-odd neurons spread throughout its arms. Each arm is able to make independent decisions, gathering sensory information to drive its movements and acting as if it contains a mini brain. The decentralised coordination may be facilitated by the intramuscular nerve cords. Genetic research is highlighting similarities between octopus brain systems and those of vertebrates, including humans.
The not-so-humble pigeon has to be included here, not least because pigeons are the forerunners of Cyril and his fellow cybirds in the Lifespinners novel. There are more than 300 species of wild pigeon, many of them very beautiful, and they have great talents, including extraordinary sight and hearing. While many people think of feral city pigeons as vermin, they have a very illustrious history. Their role in long distance communication goes back to ancient civilisations, when they signified great wealth and power. Even today, a racing pigeon has recently sold at auction for around $1.9 million.
The pigeon’s supreme navigation skills depend on a combination of scent, key landmarks, the Earth’s magnetic field and infrasound (sound waves with a frequency too low for humans to hear). They were used intensively during the first and second world wars to deliver vital messages and fly with cameras on reconnaissance missions, and they have also played a valiant role in finding and rescuing drowning sailors and passengers after shipwrecks at sea. The perfect creature, then, to morph into a highly valued smart cybird by 2048.
Edited October 2024