A juvenile whale shark, Rhincodon typus, at the platform underneath the Darwin's Arch, Darwin Island, Galápagos Whale sharks are colossal. They are the world's most giant fish, growing up to 20 m in length – more than a bowling lane and almost as long as a passenger train coach.
The unique spot pattern behind their gills can be used as their fingerprint. Thanks to that you can contribute to their protection. Find out more in the Wildbook for Whale Sharks.
Since 2016, IUCN describes the whale sharks as Endangered on its Red List. The reason is the demand for shark fins in Asia and the nature of whale shark meat, often referred to as "tofu shark". They seem to be too big to end up as bycatch, but, infuriatingly, it happens way too often.
The whale sharks live more than 100 years and take over 20 years to mature.
They are extremely valuable to the tourism industry. Whale sharks' value has been estimated at over USD 47.5 million a year – a number from 2004 that is indisputably higher today.
Nobody has ever seen a whale shark give birth or breed. At least I hope that scientists did but kept the location secret!
Whale sharks are seasonal visitors to the Galápagos. Satellite tagging and monitoring suggest that they visit the northern islands, Darwin and Wolf, typically between June and December.
A pregnant female whale shark. Darwin Island, Galápagos. Members of the Galapagos Whale Shark Project in 2014 reported sightings of 27 whale sharks, all females, all but one pregnant – this seems to be a typical situation confirmed by tourists' observations.
There is a speculation why the whale shark males avoid the Galápagos. The silky sharks like to prey on remoras. An attacked remora hides between the whale sharks' claspers to protect itself. The poor male whale shark gets hurt by the hungry silky shark in such a sensitive place. I wonder whether there is a scientific base to this.
Whale sharks were never seen feeding at Galapagos, which gives the following story* a whiff of a fairy tale.
"As with any other animal on the Galápagos, and it should be a good practice anywhere in the world, touching whale sharks is strictly forbidden. This was not a well-observed custom some time ago, perhaps ten or twenty years back when, according to a local legend, one of the naturalist guides nicknamed Zorro Plateado, or Silver Fox, used to ride the whale sharks holding on to their dorsal fin. As if this was not enough, he supposedly dragged himself from the dorsal fin and then plunged headfirst over the animal's upper lip into its gaping mouth. Disappearing into the poor whale shark's maw, he was gushed out after a moment in a shroud of his bubbles, in slight disarray, but unharmed. The animal seemed to be unperturbed, it turned slowly and swam away. The diver’s equipment could have easily injured the whale shark, and I indeed believe that such acts would not be tolerated today."
*A spoiler citation from Litt, Josef. GALÁPAGOS. Mostly Underwater Books. United Kingdom, 2017.
Similar story was also mentioned in Bantin, John. Amazing Diving Stories. United Kingdom: John Wiley & Sons Ltd, 2012.