Birds are considered reptiles under the phylogenetic classification system. This method of categorizing organisms was developed in the 1940s and is based on common ancestry.
In phylogenetics, all animals, including birds, mammals and dinosaurs, that have genetic connections to early reptiles are reptiles. Birds are traced back to the group of feathered dinosaurs that did not die off during the massive dinosaur extinction 65 million years ago. Over time, these dinosaurs evolved into birds. However, in an 18th century classification scheme, the Linnaean system, organisms are grouped together based on common traits. Since reptiles are cold-blooded and have scales, birds do not fall into this category following the Linnaean system.Learn More
Birds that can swim include penguins, cormorants, anhingas, and other darters and alcids, such as puffins, dovekies and razorbills. These birds enter water in search of prey, but penguins can spend most of their lives in the water.Full Answer >
Fossils, embryos and other clues provide evidence that fish evolved before birds. The evolutionary record indicates that limbs and wings developed over millions of years after fish evolved.Full Answer >
The anatomical and physiological features birds and mammals have in common are possessing a spinal cord and vertebral column, four-chambered hearts and warm-bloodedness. Birds and mammals also both generally invest a great deal of time and energy into raising their young, and are energetic and active consumers. Both birds and mammals have flying, fully terrestrial and amphibious members, although mammals have a wider range of lifestyles.Full Answer >
Female birds turn the end of the oviduct inside-out to lay an egg and allow the egg to emerge. A bird currently laying an egg can be identified by a rhythmic moving and opening and closing of the bill, though time varies by species from a few seconds to a few minutes. After copulation with a male bird, a female bird can store sperm in tubules.Full Answer >