Craniate facts for kids
A craniate is an animal that has a skull (also called a cranium). These animals are part of a group called the Craniata. All craniates are also chordates, which means they have a notochord (a flexible rod that supports the body) at some point in their lives.
Today, the main living craniates are hagfishes, lampreys, and all the many vertebrates with jaws, like fish, amphibians, reptiles, birds, and mammals. Scientists used to think that hagfishes were not true vertebrates because they seemed to lack a backbone. However, newer research using DNA and looking closely at their bodies shows that hagfishes actually have tiny parts of a backbone. This means that all living craniates are now considered to be vertebrates! So, for animals alive today, "craniate" and "vertebrate" mean pretty much the same thing.
Quick facts for kids Craniata |
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| A Pacific hagfish, an example of a "non-vertebrate" craniate | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Craniata Lankester, 1877 |
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What Makes Craniates Special?
Craniates are chordates that have a clear, well-formed head. This head contains a brain, eyes, and other sense organs, all protected by a hard skull made of bone or cartilage. This is why they are called "craniates" – because of their cranium (skull)!
Besides their distinct heads, craniates have many other special features that allowed them to become more complex animals. For example, their genes show that they have extra copies of certain gene families. These extra genes helped them develop more complex body plans.
Craniates are usually much more active than other simple chordates like tunicates (sea squirts) and lancelets. Because they are so active, they need a lot of energy. To get this energy, they have special body parts:
- Gills: Aquatic (water-living) craniates have gills with muscles and nerves. These help them pump water through the gills for both breathing and eating.
- Digestive System: They have muscles along their digestive system that help move food through. This allows more complex digestive systems to develop, which helps them get the most nutrients from their food.
- Circulatory System: Craniates have a heart with at least two chambers, red blood cells, and hemoglobin (a protein that carries oxygen in the blood).
- Kidneys: They also have kidneys to filter waste from their blood.
All these features help craniates be more active and successful in different environments.
Craniate Family Tree
Scientists use a "family tree" called a phylogenetic tree to show how different groups of animals are related. Here is a simplified look at where craniates fit in the larger family of chordates:
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Images for kids
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Craniata, including this extinct fish (Dunkleosteus sp.), are characterized by the presence of a cranium, mandible, and other facial bones.
See also
In Spanish: Craniata para niños
