JUN 02, 2020 9:53 AM PDT

Sea Snake Vision Has Been Evolving for Millions of Years

WRITTEN BY: Carmen Leitch

Sea snakes emerged around ten to fifteen million years ago and have been adapting to their environment for all that time. New research has learned more about how and when they gained color vision. It seems that sea snake vision has been changing over many generations, enabling them to see deep below the surface of the ocean. Reporting in Current Biology, scientists found that diving sea snakes have more in common with some fruit-eating primates than they do with other marine mammals or snakes.

An olive sea snake (Aipysurus laevis) taking a breath while foraging in Western Australia / Credit: Bruno Simoes, University of Plymouth

"In the natural world, species obviously have to adapt as the environment around them changes. But to see such a rapid change in the sea snakes' vision over less than 15 million years is truly astonishing. The pace of diversification among sea snakes, compared to their terrestrial and amphibious relatives, is perhaps a demonstration of the immensely challenging environment they live in and the need for them to continue to adapt in order to survive," said the research leader, Dr. Bruno Simões, a Lecturer in Animal Biology at the University of Plymouth.

"Our study also shows that snake and mammal vision has evolved very differently in the transition from land to sea. Sea snakes have retained or expanded their color vision compared to their terrestrial relatives, whereas pinnipeds and cetaceans underwent a further reduction in the dimensions of their color vision. This contrast is further evidence of the remarkable evolutionary diversity of snake eyesight."

Although sea snakes descended from lizards with extensive visual senses, snakes usually have color vision that is limited to two tones, probably because their ancestors lived in low-light conditions. There are about 300 terrestrial species of snakes and 63 marine snakes. Species of front-fanged and venomous elapids that are still living are ecologically diverse. Researchers wanted to know more about this diversity.

Scientists collected specimens from terrestrial and sea snakes, and analyzed the opsin genes they carried. Opsin genes produce the pigments that make eyes sensitive to visible and ultraviolet light. The visual pigments of sea snakes were found to have undergone a rapid diversification compared to their marine and terrestrial relatives.

For example, the sensitivity to UV-Blue expanded in one sea snake lineage. On the seafloor, sea snakes forage for food at a depth of over 80 meters, though they have to swim to the surface at least once every few hours to breathe. With increased sensitivity to UV-Blue, sea snakes can see better in variable light conditions, like this in the water column.

Sources: AAAS/Eurekalert! via University of Plymouth, Current Biology

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
AUG 02, 2020
Genetics & Genomics
In a First, Researchers Edit Cephalopod Genes
AUG 02, 2020
In a First, Researchers Edit Cephalopod Genes
Using the CRISPR-Cas9 gene-editing tool, researchers have knocked out a gene in a cephalopod for the first time.
AUG 24, 2020
Genetics & Genomics
Towards a Cure for Latent Herpes 1 Infections
AUG 24, 2020
Towards a Cure for Latent Herpes 1 Infections
Herpes simplex virus 1 (HSV-1) causes what's popularly known as cold sores, and is transmitted mostly through oral-t ...
AUG 27, 2020
Genetics & Genomics
Understanding How Animals Make Seasonal Adaptations
AUG 27, 2020
Understanding How Animals Make Seasonal Adaptations
Some animals don't need a new wardrobe to change with the seasons, and scientists have now learned more about how they d ...
SEP 22, 2020
Genetics & Genomics
Friedreich's Ataxia Successfully Treated in a Mouse Model
SEP 22, 2020
Friedreich's Ataxia Successfully Treated in a Mouse Model
Friedreich's ataxia causes degeneration in the peripheral nervous system, and movement is progressively impaired over ti ...
OCT 19, 2020
Clinical & Molecular DX
Making Capillary Electrophoresis Accessible for Any Lab
OCT 19, 2020
Making Capillary Electrophoresis Accessible for Any Lab
Analyzing nucleic acids through gel electrophoresis has been a staple of genetic research for decades. But using traditi ...
OCT 03, 2020
Genetics & Genomics
Genetic Changes Can Influence Cocaine Addiction
OCT 03, 2020
Genetic Changes Can Influence Cocaine Addiction
There is no treatment for cocaine addiction, which affects millions of people around the world and has a high relapse ra ...
Loading Comments...