Mammary Glands and Milk Production:
One of the defining features of mammals is the presence of mammary glands in female individuals. These glands produce milk, which serves as the primary source of nutrition for mammalian young. Both spiny anteaters and platypuses possess mammary glands and produce milk to nurture their offspring.
Hair or Fur:
Mammals are characterized by the presence of hair or fur, which provides insulation and protection from the environment. Spiny anteaters have a dense coat of coarse, spiny hair, while platypuses have a unique water-resistant fur that helps them stay warm in aquatic environments.
Endothermy (Warm-bloodedness):
Mammals are endothermic animals, meaning they can generate and maintain their body heat internally. This allows them to regulate their body temperature regardless of the external environment. Spiny anteaters and platypuses both maintain a constant body temperature through metabolic processes.
Three Middle Ear Bones:
Mammals have three small bones (malleus, incus, and stapes) in their middle ear that enhance hearing by transmitting sound vibrations from the eardrum to the inner ear. Spiny anteaters and platypuses possess these middle ear bones, enabling them to process and perceive sound effectively.
Diaphragm:
Mammals have a muscular partition called the diaphragm that separates the chest cavity from the abdominal cavity. This muscle plays a crucial role in respiration, allowing for efficient breathing. Both spiny anteaters and platypuses have a diaphragm, enabling them to breathe effectively.
Viviparity (Live Birthing):
Most mammals give birth to live young, a characteristic known as viviparity. While the spiny anteater typically gives birth to a single live offspring after gestation, the platypus is a unique mammal that lays eggs. However, the platypus still displays mammalian characteristics after hatching, such as nursing its young with milk produced by mammary glands.
In summary, spiny anteaters and platypuses are classified as mammals based on their possession of key mammalian traits, including mammary glands for milk production, hair or fur for insulation, endothermy for temperature regulation, three middle ear bones for enhanced hearing, a diaphragm for efficient breathing, and viviparity (live birth or nurturing of hatched young with milk).