An invertebrate is an animal without a backbone, whereas a vertebrate has a spine. Some 98 percent of the known animal kingdom is made up of invertebrates, with the vertebrates -- mammals, reptiles and bony fish -- comprising the rest.
The seahorse is a vertebrate of the scientific phylum Chordata. Members of this classification all have spines. This sea creature that measures between 0.9 to 12 inches in length has a bone structure composed of tiny plates covered by a thin, almost translucent skin, instead of scales like other fish. There are 32 seahorse species globally, and most prefer temperate to tropical waters and coral reef habitats. He uses his long snout to suck up food and his tail to move and anchor himself to rocks and coral. The male seahorse incubates the female's eggs and gives birth, which makes the seahorse one of nature's more unusual creatures.
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Based in London, Eleanor McKenzie has been writing lifestyle-related books and articles since 1998. Her articles have appeared in the "Palm Beach Times" and she is the author of numerous books published by Hamlyn U.K., including "Healing Reiki" and "Pilates System." She holds a Master of Arts in informational studies from London University.