 Wysłany: Nie 2:36, 25 Lut 2007 Temat postu: boa po angielsku |
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| Boas are a type of snake that are members of the Boidae family. Boas are basal snakes that are "primitive" in evolutionary terms (i.e. less derived). They are constrictors and most give birth to live young. They have anal spurs, a pair of claws on each side of the cloaca which assist in mating. Boas are named after cows (Latin: bos) because of the old myth that boa snakes pursue cows and suckle them until they are drained to death.
Boas have two subfamilies: Boinae or true boas and Erycinae or sand boas. Pythons are sometimes classified as a subfamily of Boidae, but are frequently listed under their own family, Pythonidae. Sand boas are also frequently listed under their own family, Erycidae.True boas are medium sized to large snakes. Females are usually larger than their male counterparts. Boas contain many subspecies based on locality. They include Colombian, Suriname, Bolivian, Peruvian, Hog Island, Long Tail Peruvian, Argentine and more. The boas from the amazon basin are the most colorful possessing bright cherry red tails. It used to be said that boas were New World Snakes and pythons were Old World Snakes, but, with boas found on Madagascar, Fiji Islands, and the Solomon Islands, this is not quite true. Instead, it is possible that boas have survived in evolutionarily isolated areas. South America, until a few million years ago, had a distinct fauna that included marsupial mammals; with the land bridge to North America, boas have migrated north as placental mammals and colubrids (for example) have migrated south. |
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