While a lot has been known about whale sharks in general, information on the young ones of this species continues to be a mystery for mankind. Other than the relatively rare nature of these young ones, our limited knowledge about them can be attributed to the lack of data on reproduction in this species. As of today, only one pregnant female whale shark has been caught in the wild and studied, and most of the information on the reproduction in this species that we have can be attributed to this study alone.
Whale Sharks: An Introduction
The whale sharks (Rhincodon typus) are a species of shark found in tropical and warm-temperate waters of the world. Other than their mammoth size, they are typically characterized by their gray skin with pale yellow spots and stripes and a white underbelly. On an average, this species can grow on to attain a length of 10-11 meters and weigh up to 20.6 tons, which makes it the biggest fish in the world. While the largest ever caught whale shark specimen was 12.2 meters in length, the heaviest ever weighed 79,000 lb. Being a filter feeder, the whale shark usually feeds on krill, algae, plankton, and sometimes on small squids and vertebrates. Even though it is the largest fish in the world, the whale shark doesn't pose any threat to human beings. In fact, they are considered to be one of the most docile species in the world by divers, who often hitch a ride on them.
Facts about Baby Whale Sharks
Measuring 10.7 meters and weighing approximately 16 tons, the only female whale shark specimen to have been studied was caught in July 1996. Studies revealed that there were more than 300 young ones in its body, which made the scientists come to a conclusion that whale sharks are ovoviviparous in nature i.e. they produce young ones from the eggs which hatch within their body. On an average, a female whale shark gives birth to somewhere around 300 young ones - each of which measures approximately 16-24 inches in length. There do exist some sources which suggest that the young ones of whale shark grow at the rate of 49 cm a year, but lack of data has made it difficult for the scientists to come to a consensus on this issue. Similarly, juvenile whale sharks weight seldom exceeds a few lbs which is again in stark contrast of an adult whale shark which weighs several tons. The upper fin on their tail is larger than the lower fin, which is in stark contrasts to the crescent shaped tails that the adults sport.
With their small size, the food choice for juveniles is limited, with most of them resorting to krill as their primary food source. The fact that the young ones of a fish species, which boasts of being the biggest shark in the world, measure only around 20 inches is bound to come as a surprise for many. In fact, this small size of whale shark young ones makes them an easy prey for a number of predators in the vast marine biome. While the average lifespan of whale shark species is known to be somewhere around 70-100 years, the individuals belonging to this species only attain sexual maturity at the age of 30 years. While some scientists believe that the breeding ground for this species is restricted to open oceans, few sightings close to the shore suggest that the breeding ground and the feeding ground of this species may be the same.
Over the last few years, researchers have started stressing on the importance of studying breeding pattern in this species as it has been observed that their number is rapidly decreasing in the wake of large-scale hunting. In fact, the International Union for Conservation of Nature (IUCN) has already enlisted the whale shark as a threatened species, while the wildlife experts are of the opinion that the ongoing trend will result in extinction of this species within a few decades to come, and that is something which is bound to result in a domino effect in the marine food web.