A testament to the evolution of these large sea creatures is how they have metamorphosed to digest seaweed.
Sharks are popular as a predator specie which may explain why Mariners once referred to them as seadogs. In the world of sharks, the whale shark (Rhincodon typus) stands out as the biggest of its species that have been discovered. Asides their intimidating size, it has also been detected that whale sharks are utility consumers. For a specie popularly known to be carnivorous especially with its crustaceans (krill) dominated diet, whale sharks have also been discovered to be high consumers of seaweed. This discovery makes them the world largest Omnivore with some whale sharks reaching about 40 tons in weight. Prior to this time the Kodiak bears used to be known as the world’s largest Omnivores.
The new discovery is based on Whale Shark skin samples from the Ningaloo reef in Western Australia which was analysed by scientists. Whale sharks can grow up to an average of 12 meters (40 feet) and this makes them the largest sea creatures on the planet. They were generally known as filter feeders feeding on crustaceans, plankton, small fishes, and shrimps which they strain using their gills after consuming abundant volumes of water. The recent findings published in Ecology journal in July 19 has now created the need for further studies to be carried out on this large sea creature.
There has been a general misconception that while giant land animals are herbivores, giant sea animals are carnivores but this recent discovery has now blurred the lines of distinction between evolution of land animals and sea animals.
To carry out this study, the common food sources of shark which include crustaceans, plankton and seaweed were analysed for their amino and fatty acids content. The analysed data was then compared with the content of the whale shark skin samples available. The result revealed that at type of brown seaweed consisting of algae; sargassum was the dominant in the diet of whale sharks.
To explain this evolutionary pattern researchers think that the ability to digest accidentally swallowed seaweed became a necessity for whale sharks in order to avoid incessantly expelling them once swallowed. Expelling this food must have been really time and energy consuming for the giant sea creature.
Another interesting angle worthy of attention is the idea that a broader diet will help Whale Sharks withstand the adverse effect Climate change may pose to the ecosystem particularly the marine habitat. However this situation is more of a gift and a curse. One of the fingered culprits that has worsened climate change conditions is improper waste management which has released plastics and other toxic substances to large water bodies. If the whale shark swallows just about anything without discrimination, then there is a high likelihood that ocean borne plastics will be part of their diet.
Researchers including Australian Institute of Marine Science’s Mark Meekan who is a fish biologist opined that consumption of plastics will hurt whale sharks on the long run. Although they may eliminate some of these plastic, swallowing pieces of plastics may cause whale sharks to vomit their meals and mess up their guts and digestive system.
As originally reported:
https://www.livescience.com/whale-sharks-largest-omnivores
