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Whale shark

life science Maturity 7-9 Next article →

The whale shark, known scientifically as Rhincodon typus, is a massive, slow-moving fish. It is the largest known extant fish species in our oceans today. While its name suggests it is related to whales, it is actually a shark. It is the only living member of the genus Rhincodon. It is also the only surviving member of the family Rhincodontidae. This shark holds many size records in the animal kingdom. Most notably, it is the most massive living non-cetacean animal. A cetacean is a group of marine mammals like whales and dolphins.

Whale Shark and Freediver
Whale Shark and Freediver

To survive, the whale shark uses a method called filter feeding. Its mouth is located at the front of its head rather than underneath. This mouth can be exceptionally wide, sometimes measuring over 1.5 meters across. Inside, the shark has over 300 rows of tiny teeth. It also possesses 20 specialized filter pads that act like a sieve. As the shark swims, it processes over 6,000 liters of water every hour. This process allows it to consume plankton, krill, fish eggs, and small schooling fish. These include species like sardines and anchovies.

Whale Shark (Rhincodon typus) with open mouth in La Paz, Mexico
Whale Shark (Rhincodon typus) with open mouth in La Paz, Mexico
Whale Shark 1 AdF
Whale Shark 1 AdF

The whale shark has a very distinct physical appearance. Its skin is dark grey with a white belly. The body is marked by an arrangement of pale grey or white spots and stripes. These patterns are unique to each individual shark. The skin is up to 10 centimeters thick and feels very hard and rough. Along its sides, the shark has three prominent ridges. It has several fins, including two dorsal fins set far back on the body. Its caudal fin, or tail, has a larger upper lobe than the lower lobe. This shape is known as a heterocercal fin.

These giants are highly migratory and travel thousands of miles. They move across tropical oceans to find seasonal food sources. Large groups often gather at specific coastal sites. These include Ningaloo Reef in Western Australia and the Yucatan Peninsula in Mexico. Other locations include the coasts of India, the Philippines, and Tanzania. In 2009, more than 400 whale sharks gathered off the Yucatan Coast. This was one of the largest gatherings ever recorded.

Whaleshark in Oslob Philippines
Whaleshark in Oslob Philippines
Rémoras blancas (Remora albescens) en un tiburón ballena (Rhincodon typus), La Paz, Baja California, México, 2024-12-20, DD 07
Rémoras blancas (Remora albescens) en un tiburón ballena (Rhincodon typus), La Paz, Baja California, México, 2024-12-20, DD 07

Scientists have studied these animals for nearly two centuries. The species was distinguished in April 1828 after a specimen was harpooned in South Africa. Andrew Smith, a military doctor, described the shark the following year. We also know they are very ancient. The earliest fossil teeth found belong to the Late Oligocene period in South Carolina. By the Early Miocene, their fossils appeared in France and Costa Rica. Today, we can study their entire genome, which was published in 2017.

Okinawa Aquarium
Okinawa Aquarium

The whale shark has amazing biological adaptations for deep diving. Its eyes can retract deep into their sockets for protection. The eyes also have dermal denticles, which are tiny tooth-like structures, on their surface. A special light-sensing pigment called rhodopsin helps them see. In most animals, this pigment is sensitive to green light. In whale sharks, two amino acid substitutions make it sensitive to blue light. This is the color that dominates the deep ocean. This allows them to see well at both the surface and at depths of 2,000 meters. They can even stay at these deep levels for three days or more.

Whale Shark and Freediver
Whale Shark and Freediver

Measuring these animals is a difficult task for researchers. It is hard to get accurate lengths for sharks in the water. Some scientists use photogrammetry, which uses photos to measure objects. Size estimates for these sharks vary widely. Some reports suggest they can reach 18 meters in length. A 2020 study at Ningaloo Reef showed sexual dimorphism, meaning males and females grow differently. Males averaged about 10 meters, while females were estimated to be much larger. Despite their size, they are docile and pose no significant threat to humans. However, they are currently listed as an Endangered species. Their populations have declined by more than 50% over the last 75 years due to fishing and ship collisions.

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🖼️ Images & Media (8)
File:Whale Shark 1 AdF.jpg
Whale Shark 1 AdF.jpg
File:Rémoras blancas (Remora albescens) en un tiburón ballena (Rhincodon typus), La Paz, Baja California, México, 2024-12-20, DD 07.jpg
Rémoras blancas (Remora albescens) en un...
File:Whale Shark (Rhincodon typus) with open mouth in La Paz, Mexico.jpg
Whale Shark (Rhincodon typus) with open...
File:Whaleshark in Oslob Philippines.png
Whaleshark in Oslob Philippines.png
File:Whale Shark and Freediver.jpg
Whale Shark and Freediver.jpg
File:Male whale shark at Georgia Aquarium.jpg
Male whale shark at Georgia Aquarium.jpg
File:Okinawa Aquarium.jpg
Okinawa Aquarium.jpg
Nadando con un Tiburón Ballena- Swimming...
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