The bizarre phenomenon of regeneration in animals.
I have always been fascinated by weird evolutionary adaptations in animals brought about by the quest for survival. Regeneration is likely one of the most useful abilities. But this adaptation is one that has considerably regressed along its way through evolutionary lines as body complexity increased. Various forms of regeneration, however, are still exhibited by many species, and even complex animals such as ourselves still maintain some basic or latent regeneration capabilities.
Animals that can regenerate limbs
Animals with the ability to regenerate limbs are extraordinary. We know of lizards being able to grow back missing tails but many other species share similar traits.
Insects and crustaceans are able to re-grow missing limbs too, but in arthropods regeneration is limited as it it is linked to the moulting process.
More primitive species are able to regenerate entire individuals from a severed limb or fragment. Sea stars and sponges can do this through fragmentation, and the hydra through budding. But even more incredible is the ability to regenerate parts of complex structures such as organs and components of the nervous system.
Growing new organs
The Zebrafish is able to regrow its heart, retina and other complex tissues. The Mexican Salamander, or Axolotl, an archetype for regeneration, can not only to regrow missing appendages but can also regenerate damaged parts of its brain and spinal cord.
The University of New South Wales (UNSW) are currently researching the possibility of replicating the regeneration abilities of the salamander in humans using our own cells. In addition to replicating limb regeneration, research indicates that these remarkable creatures may also hold the secret to longevity within their DNA which is adapted to counter the aging process, giving some of these animals biological immortality. Understanding this phenomenon could lead to further medical breakthroughs for us.
But do we deserve it?
The unavoidable elephant in the room is the issue of animal experimentation. When it comes to medical research, a lot is considered acceptable. However the question is not just what can be done for the benefit of mankind – but also at what cost?
Sadly, the future of some of these animals may not be very bright. Axolotls are on the critically endangered list due to habitat pollution. They are endemic to a small area around Xochimilco in southern Mexico where pollution of the Xochimilco Lake has become a major threat. According to the IUCN, habitat restoration efforts, in conjunction with conservation education and ecotourism initiatives are underway to alleviate the problem and hopefully reintroduce captive colonies into their natural habitat.
We have much more to learn from the weird and wonderful creatures that inhabit the earth alongside us, but I believe that the protection and ethical treatment of all species should always take precedence over human advancement.
Did you know? Sea stars, which are commonly referred to as starfish as they had originally been named, are in fact not fish. The term sea star was later allocated to the species. Sea stars belong to the echinoderm phylum whereas fish fall under the phylum chordata.