The majority of mammals have seven cervical vertebrae or bones in the neck, including bats, giraffes, whales, and humans. The exceptions are the manatee and the two-toed sloth, which have only six cervical vertebrae, and the three-toed sloth with nine cervical vertebrae. Mammals are vertebrates by definition, which means that all mammals have an internal bony support structure to which muscles and ligaments are attached.
The basic plan of the mammalian skeleton is fairly straight forward. It consists of a head at one end of a vertebral column to ribs which support the working organs and four limbs for locomotion. This vertebral column ends in a tail. The large range of lifestyles and habitats used by mammals means that a great deal of variation exists between different groups. Some species lack a tail, others lack apparent hind limbs and the skull is very variable.
The basic plan of the mammalian skeleton is fairly straight forward. It consists of a head at one end of a vertebral column to ribs which support the working organs and four limbs for locomotion. This vertebral column ends in a tail. The large range of lifestyles and habitats used by mammals means that a great deal of variation exists between different groups. Some species lack a tail, others lack apparent hind limbs and the skull is very variable.