Grapsus grapsus, commonly known as the red crab or rock runner crab, is a species of crustacean that lives on the rocky coasts of the Pacific Ocean, from the Galapagos Islands to the coasts of Central and South America. This crab is one of the most common and visible in intertidal zones, where it moves with agility along rocks close to the water.
The body of Grapsus grapsus is flattened and can reach a size of up to 8 centimeters wide. Its coloration is one of its most striking characteristics, especially in adult individuals, which present a range of vibrant colors that include shades of red, orange, yellow and blue. Juveniles, on the other hand, are darker, with brown and black patterns, which provides them with effective camouflage in their rocky environment.
This crab is mainly herbivorous, feeding on algae that it scrapes from rocks with its legs and jaws. However, it can also consume decaying organic matter, small mollusks and the remains of dead animals, making it an opportunistic feeder. Its ability to adapt to different food sources helps it survive in a changing environment such as the intertidal.
Grapsus grapsus is known for its agility and speed, allowing it to move easily over rocky and steep surfaces, even in rough surf conditions. Its legs are adapted to hold onto wet rocks, preventing it from being swept away by the waves. In addition, it is able to swim briefly if necessary, although it prefers to stay on dry land near the water.
This crab plays an important role in coastal ecosystems, helping to control algae growth on rocks and acting as a scavenger, contributing to the cleanliness of its environment. In the Galapagos Islands, in particular, it is an iconic species, often photographed due to its colour and constant presence on rocky shores.
Approximate measurements of the crab:
The body of Grapsus grapsus is flattened and can reach a size of up to 8 centimeters wide. Its coloration is one of its most striking characteristics, especially in adult individuals, which present a range of vibrant colors that include shades of red, orange, yellow and blue. Juveniles, on the other hand, are darker, with brown and black patterns, which provides them with effective camouflage in their rocky environment.
This crab is mainly herbivorous, feeding on algae that it scrapes from rocks with its legs and jaws. However, it can also consume decaying organic matter, small mollusks and the remains of dead animals, making it an opportunistic feeder. Its ability to adapt to different food sources helps it survive in a changing environment such as the intertidal.
Grapsus grapsus is known for its agility and speed, allowing it to move easily over rocky and steep surfaces, even in rough surf conditions. Its legs are adapted to hold onto wet rocks, preventing it from being swept away by the waves. In addition, it is able to swim briefly if necessary, although it prefers to stay on dry land near the water.
This crab plays an important role in coastal ecosystems, helping to control algae growth on rocks and acting as a scavenger, contributing to the cleanliness of its environment. In the Galapagos Islands, in particular, it is an iconic species, often photographed due to its colour and constant presence on rocky shores.
Approximate measurements of the crab:
- Scale 1:4 Complete
- Length 64 mm
- Height 20 mm
- Width 35 mm
- Shell length 20 mm
- Scale 1:1 Complete
- Length 252 mm
- Height 77 mm
- Width 138 mm
- Shell length 80 mm
