Birds and Mammals

Contour feather

The outermost layer of feathers that give a bird its shape. Contour feather. A contour feather is a type of feather that covers a birds body and helps it to maintain its shape and streamline for flying.

Diaphragm

The muscle below the lungs that controls breathing. Diaphragm. The diaphragm is a dome-shaped muscle that helps pump air into and out of the lungs.

Down feather

A soft, fluffy feather that traps heat to keep birds warm. Down feather. Down feathers are tiny, insulating feathers that help birds stay warm by trapping heat.

Gestation period

The time between fertilization and birth, when young develop in the uterus. Gestation period is the duration a baby grows inside its mother's womb before being born.

Mammal

A warm-blooded vertebrate whose young feed on milk produced by the mother. Mammal. Mammals are animals with backbones that nurse their babies with milk.

Mammary gland

Milk-producing gland in female mammals. Mammary gland. The mammary gland is an organ in female mammals that produces milk to feed their young.

Marsupial

A mammal that carries its young in a pouch. Marsupial. A marsupial is a type of mammal that gives birth to underdeveloped young, which then grow in a pouch on the mother's body.

Monotreme

A mammal that reproduces by laying eggs monotreme. Monotremes are a unique group of mammals that lay eggs instead of giving birth to live young.

Placenta

An organ that connects a fetus to its mother, providing it with nutrients and removing waste. Placenta. The placenta is an organ that supplies food and oxygen to the growing baby and removes waste.

Placental mammal

A mammal that nourishes its unborn offspring through a placenta in the uterus. Placental mammal. A placental mammal is an animal that develops its baby inside the mothers body, using a special organ called the placenta to provide food and oxygen.

Preening

The grooming and maintenance of their feathers by birds. Preening. Preening is when birds clean and organize their feathers to help them stay healthy and fly well.