Plough-nosed chimaeras facts for kids
Quick facts for kids Plough-nosed chimaeras |
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| Callorhinchus milii | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Order: | Chimaeriformes |
| Family: | Callorhinchidae Garman, 1901 |
| Genus: | Callorhinchus Lacépède, 1798 |
| Species | |
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C. callorynchus |
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The plough-nosed chimaeras or elephantfish are a special type of fish called Callorhinchus. They are the only living group in their family, Callorhinchidae. These fish look a bit like other chimaeras, but they have a unique, long, flexible snout that looks a bit like a farmer's plough.
You can only find elephantfish in the oceans of the Southern Hemisphere. They live near the bottom, usually on muddy or sandy areas. They eat by filtering food from the ocean floor, mostly small shellfish. Elephantfish lay their eggs on the seabed, and the babies hatch after about 8 months. While they are not currently a main focus for conservation, they could be at risk from too much fishing.
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What Do Elephantfish Look Like?
Plough-nosed chimaeras can grow to be about 70 to 125 centimeters (about 2.3 to 4.1 feet) long. They are usually black or brown, or a mix of both colors. Their special snout makes them easy to spot, but they have other cool features too.
- Fins: They have large pectoral fins, which help them swim fast. They also have two dorsal fins that are far apart. The second dorsal fin is much smaller than the first.
- Gill Opening: Each pectoral fin has one gill opening in front of it.
- Spine: There is a spine between their two dorsal fins.
- Tail: Their tail fin is split into two parts, with the top part being larger.
- Eyes: Their eyes are high on their head and are often green.
The elephantfish uses its snout to search the sea bottom for small animals and fish to eat. The rest of its body is flat and long. Its mouth is right under the snout, and its eyes are on top of its head. They have wide, flat teeth that are perfect for crushing shellfish. These fish have two pairs of teeth in their upper jaw and one pair in their lower jaw. Their snout can also sense movement and electric fields, which helps them find food.
Elephantfish Family Tree
Elephantfish are a very old group of fish with jaws. They have a skeleton made of cartilage, just like sharks. However, they are in a different group called holocephali. This makes them important for scientists who study how jaws developed in early fish.
Interestingly, the Callorhinchus has the smallest genome (all its genetic information) among cartilaginous fish. Because of this, scientists have suggested using it to study the entire genome of cartilaginous fish. People often say elephantfish look like a mix between a shark and a ray. But you can tell them apart from sharks because they have a special flap called an operculum covering their gills. Also, their skin is smooth, not rough like a shark's. Unlike sharks, whose jaws are loosely connected to their skull, elephantfish have jaws that are fused to their skulls.
Where Do Elephantfish Live?
These fish live in warm and mild waters in the Southern Hemisphere. There are three main types of living elephantfish:
- South American Elephantfish (Callorhinchus callorynchus): These live off the coast of southern South America. You can find them from Tierra del Fuego up to Peru in the Pacific Ocean and southern Brazil in the Atlantic Ocean. People fish for them all year in Brazil and Argentina.
- Cape Elephantfish (Callorhinchus capensis): These are found in the oceans off southern Africa, near Namibia and South Africa.
- Australian Ghostshark (Australian ghostshark|Callorhinchus milii): This type lives in the southwestern Pacific Ocean, close to Australia and New Zealand. They prefer warmer, milder waters. During spring and summer, these elephantfish travel to estuaries and bays closer to shore to mate.
How Elephantfish Find Food
Elephantfish are mostly filter feeders. This means they eat by sifting through the sandy bottom of the ocean or continental shelves. Their long snout helps them a lot with this. Their main food is molluscs, especially clams. They also eat other small animals without backbones, like jellyfish or small octopuses. They are not able to catch and eat fast-swimming bony fish.
Elephantfish Life Cycle
Elephantfish are oviparous, which means they lay eggs. They usually mate and lay eggs during spring and early summer. Male elephantfish have special parts called claspers near their pelvic fins, just like sharks. These are used to transfer their reproductive cells. They move to shallower waters to lay their eggs. The male also has a club-like part on its head that helps it hold onto the female during mating.
The eggs are released onto the muddy seabed, usually in shallow water. At first, the eggs are golden yellow. They turn brown, and then black, just before hatching. The babies stay in the egg for about 8 months, getting all their food from the yolk. Once they hatch, the young fish instinctively swim to deeper water. The egg cases are long and flat and can look a bit like pieces of seaweed.
Types of Elephantfish
There are three living species (types) of elephantfish, all in the same group:
- Callorhinchus callorynchus Linnaeus, 1758 (also called Ploughnose chimaera, American elephantfish, or cockfish)
- Callorhinchus capensis A. H. A. Duméril, 1865 (Cape elephantfish)
- Callorhinchus milii Bory de Saint-Vincent, 1823 (Australian ghostshark)
There was also a fourth species, C. torresi Otero et al., 2014, but we only know about it from fossils found from the time of the Cretaceous period.
Fishing and Protecting Elephantfish
Right now, there are no big efforts to protect elephantfish. However, people fish for them a lot in South America for food. This means they could be easily overfished. The biggest danger to these fish is trawling or net fishing, where many fish are caught very quickly.
Once caught, the fish are often sold as "whitefish" or "silver trumpeter fillets," often used in fish and chips. Australia is a common place where these fish are sent. The IUCN (a group that tracks how endangered animals are) lists all three living types of elephantfish as "Least Concern" because they are still common. While Australia and New Zealand have rules about how many can be caught, this is the main conservation effort so far. Sometimes, elephantfish are caught for aquariums, but this is much less common than fishing for food.
