Some Types of Snakes Thread snakes (Leptotyphlopidae) include the smallest snakes, extremely slender forms less than ten centimeters (about four inches) long. Most are burrowers, but some have been found in bird nests. These were presumably brought to the nests by birds as food for their young, but escaped and subsist on the insects that also inhabit the nests. Boas and pythons (Boidae) include the world's largest snakes. Although mythical accounts abound, individuals of some species (invariably females) may exceed twenty feet, and a very few may approach thirty. Tales of larger snakes are probably fanciful. Large snakes can exploit large prey, and can swallow deer, pigs, and even humans. Sea snakes (subfamily Hydrophiinae) are the most aquatic snakes. Some species never leave water and give live birth. All are venomous and most feed on fish. King cobras (Ophiophagus hannah) are the longest venomous species, sometimes exceeding five meters (over sixteen feet) in length. King cobras feed largely on other snakes and are one of the few species that builds nests and cares for its eggs.
The Roots of Ethology Ethology is a young science, yet it is also a science with a long history. Prior to the late nineteenth century, naturalists had accumulated an abundance of information about the behavior of animals. This knowledge, although interesting, lacked a theoretical framework. In 1859, Charles Darwin published On the Origin of Species, and with it provided a perspective for the scientific study of behavior. Behavior was more central to two of Darwin's later books, The Descent of Man (1871) and Expression of the Emotions of Man and Animals (1873). By 1973, the science of ethology was sufficiently well developed to be acknowledged by the presentation of the Nobel Prize for Physiology or Medicine to Nikolaas Tinbergen, Konrad Lorenz, and Karl von Frisch for their contributions to the study of behavior. The work of thesemenwas central to the development of modern ethology. The experimental studies of Frisch revealed the dance language of the honeybee and ways in which the sensory perception of the bees differed from our own sensory world. An awareness of species-specific sensory abilities has provided an important research area and has emphasized a factor that must be considered in the experimental design and interpretation of many types of behavioral research. Tinbergen studied behavior in a variety of vertebrate and invertebrate organisms. He was good both at observation of animals in their natural habitat and in the design of simple but elegant experiments. His 1951 book, The Study of Instinct, is a classic synthesis of the knowledge that had been gained through the scientific study of animal behavior at that time. Konrad Lorenz is considered by many to be the founder of ethology, because he discovered and effectively publicized many of the classic phenomena of ethology. Pictures of Lorenz being followed by goslings are almost a standard feature of texts that discuss the specialized form of learning known as imprinting. In natural settings, imprinting allows young animals to identify their parents appropriately. Another contribution of Lorenz was his book King Solomon's Ring: New Light on Animal Ways, published in 1952. This extremely readable book raised public awareness of the scientific study of animal behavior and kindled the interest of many who eventually joined the ranks of ethologists.
