Chordates, members of the animal phylum Chordata, which includes all mammals, birds, amphibians, reptiles, and fish. There are about 45,000 species of chordates. They are classified in four subphyla, the largest of which contains the vertebrates. All chordates share three basic characteristics. The first characteristic is a single dorsal nerve cord, which in mammals takes the form of the brain and spinal cord. The second is a flexible rod of cells called a notochord, which in vertebrates takes the form of the backbone. The third is the presence of gill slits at some stage during the development of the animal. All chordates have bilateral symmetry.
If the animal world were school, otters would be those kids who never leave the playground. Always begging for five more minutes of recess, otters take playtime very seriously.
Plan ahead to find pet-friendly hotels that will suit the needs of your pet and double check all the facts before leaving home. Take this quiz to learn more about pet friendly hotels.