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Small Mammals of Colorado
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Mammals are vertebrate animals with hair. Vertebrates are animals with backbones. Other vertebrate animals are bony fish, sharks, amphibians, reptiles and birds. Like birds, mammals are warm-blooded. Their hearts have four chambers with separate channels to carry oxygen-rich blood to their brains, muscles and tissues. Once the oxygen gets used, blood is carried to the lungs for more oxygen.
Mammals are warm-blooded animals. That means they keep a high, constant body temperature even though the outside temperatures change. Insulation, such as hair or fat, helps keep mammals warm. Mammals arose from reptiles about 240 million years ago. They began to become really successful and important in ecosystems after dinosaurs became extinct about 65 million years ago. Mammals are different from reptiles in a number of ways.
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Jaws/Teeth of Mammals
Mammals' Hair
Mammary Glands
Brains of Mammals
Learning Process
Population of Mammals
List of Colorado Mammals
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Jaws/Teeth of Mammals
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Mammals' jaws move less than reptile jaws. But, the jaws of mammals are stronger, which help them use their fancy teeth better. Mammals' teeth have three distinct features. First, their teeth are specialized from front to back. Second, their teeth are set firmly in sockets. Third, mammals have two sets of teeth - "baby teeth" and permanent ones. Mammals have four kinds of teeth: incisors for nipping, canines for grasping prey, premolars and molars for crushing, shearing, and grinding food. Molars are present only in permanent teeth.
These special kinds of teeth help mammals chew their food better. Once the small bits of chewed food enter the digestive tract, they mix with digestive juices and are digested fast. That gives mammals fuel so they can stay active regardless of the temperature outside.
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Mammals' Hair
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We think of mammals as reptiles with glorified hair. Many basic features of mammals are associated with their hair. Originally, their hair helped insulate them. But their hair began serving other purposes as well, such as helping them camouflage, sense their environment, warn them of dangers and recognize the opposite sex.
Attached to each hair is a tiny muscle that can raise the hair to trap warm air. In humans, muscles contract and raise "goose bumps" when they are cold. Each hair has a gland that secrets oil to waterproof hair. Sweat glands release water and salts that evaporate from the skin and hair, helping cool the body.
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Mammary Glands
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Mammary glands produce milk, a mixture of water, carbohydrates, fats, proteins and salts. Milk gives newborn, nursing mammals a nutritional "jumpstart." Nursing also lets newborns interact with their mothers and littermates, helping them become trained and socialized.
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Brains of Mammals
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An advanced brain is another key to the success of mammals. The basic parts of mammals' brains were present in their ancestral reptiles and even fish. Mammals, however, have developed parts of their brains used for learning.
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Learning Process
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Mammals are more highly dependent on learning than most other animals are. Mammals don't rely much on instinctive ways of solving problems. Instead they piece together solutions based on experience. The cerebral cortex is their center of learning in their brains and is larger than in other animals.
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Population of Mammals
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There are about 4,400 species of living mammals, much fewer than species of birds, reptiles, fish, or other invertabrates, such as insects and snails. Mammals impress us not by their number of species, but by the number of body types. The common ancestor of mammals that use placentas to feed embryos and of marsupials that carry their young in pouches was a rat-to-opossum sized mammal. That mammal was four-legged, ate plants as well as meat, and lived on land.
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List of Colorado Mammals
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For a complete list of the mammals that can be found in Colorado, please visit the web site below.
Related Links:
Division of Wildlife
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