Whalesucker facts for kids
Quick facts for kids Whalesucker |
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The whalesucker (Remora australis) is a special type of remora fish. It gets its name because it sticks only to cetaceans, which are marine mammals like whales and dolphins. You can find whalesuckers all over the world in warm, tropical waters. For example, they live from Texas to Brazil in the western Atlantic Ocean. They also live from Vancouver Island to Chile in the eastern Pacific Ocean.
Whalesuckers are the rarest members of the remora family. This might be because it's hard to find and study them in the wild. They are usually found attached to their large hosts.
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What Does a Whalesucker Look Like?
The whalesucker has a unique feature: a large sticky disk on top of its head. This disk is the biggest among all remoras. It has 25 to 28 special ridges called lamellae. The disk can be almost half the length of the fish's body.
The whalesucker's head is also quite big. Its body can grow up to 76 centimeters (about 30 inches) long. Whalesuckers are usually brown, dark brown, or grayish-brown. Their fins match their body color. Younger whalesuckers might have stripes or spots. Older ones, over 35 cm (14 inches), often have yellowish fins.
How Whalesuckers Live with Other Animals
Whalesuckers often attach to blue whales. They have also been seen with spinner dolphins. Whalesuckers eat tiny parasites and dead skin from their hosts. They also eat feces (poop) and vomit from the dolphins. This helps both the whalesucker and its host. This type of relationship is called mutualism.
Whalesuckers usually stick to the sides or belly of dolphins. This helps them move easily through the water. It also helps them find food. If a whalesucker feels threatened, especially a small one, it will move to the other side of its host for safety.
Sometimes, whalesuckers can be a bit of a bother to their hosts. Their sticky disks can rub the host's skin. They might also attach in awkward places, like near a whale's blowhole. Dolphins and other animals might spin around to try and shake them off.
Whalesuckers and Blue Whales
The relationship between whalesuckers and blue whales is a great example of mutualism. Whalesuckers stick to blue whales, even coming out of the water briefly when the whale surfaces. They also move around on the whale to avoid predators while they are eating.
Whalesuckers benefit in several ways. They get protection from predators by staying with the huge whale. They also get food from the whale's parasites and skin. Being with the whale also helps them find mates.
Blue whales benefit by having parasites and dead skin cleaned from their mouth and gill areas. Whalesuckers also help blue whales by reducing drag. The whalesucker can swim near the whale's surface before attaching. This helps it keep up with the fast-moving whale. Blue whales can swim at speeds of about 7.6 km/h (4.7 mph) and even up to 14 km/h (8.7 mph). Whalesuckers, being much smaller, can match these speeds.
Whalesuckers use their sticky disk to attach to the whale. They often stick right behind the whale's blowhole. They also attach on, behind, or above the pectoral fin, and near or behind the dorsal fin. This helps them stay close to the whale and reduce drag. They also try to stay away from the whale's underside to avoid seabirds that might try to eat them.
The Whalesucker's Sticky Disk
One of the most amazing things about the whalesucker is its sticky disk. This oval-shaped disk is on top of its head. It has two layers of lamellae that let the remora stick to and unstick from the skin of larger animals. The disk is thought to have developed from dorsal fin spines. It helps the fish stick to rough surfaces. An average whalesucker's disk is about 11 to 19 cm (4 to 7.5 inches) long.
The sticky disk works using both friction and suction. Small spines on the lamellae rotate inside the disk. This creates friction to help the fish resist drag. A thick layer of cells called epithelium seals the edge of the disk. This creates equal pressure, allowing the whalesucker to stick firmly.
However, if the pressure isn't equal, the whalesucker can lose its suction. This can happen if water seeps in from outside the disk. The whalesucker's cranial veins (veins in its head) are also special. They are larger than in other fish and help the disk work like a hydraulic press. This helps keep the pressure balanced when it attaches.
Whalesucker Relatives
The whalesucker shares similar body parts with other remora species. They all have a strong lower jaw that sticks out. This jaw becomes almost flat with the sticky disk. Remoras can also move across their host's skin. This lets them scoop up parasites and other bits of food into their mouths.
The closest relative to the whalesucker is the cobia, also known as the black salmon (Rachycentron canadum). While the cobia doesn't have a sticky disk, both species show similar behaviors. They both stay close to larger animals for protection and food. This shows how the whalesucker's body and behavior are connected to its family tree.
